WO2016098992A1 - Display device and control method therefor - Google Patents

Abstract

A display device and a control method therefor are disclosed. A display device according to an embodiment of the present invention comprises: a reception unit for receiving content including a high dynamic range (HDR) image and metadata of the content (the metadata include one or more pieces of information representing the dynamic range of the image, the peak luminance of the image and the luminance curve of the image); and a control unit, wherein the control unit obtains an average picture level (APL) of the image included in the received content, detects the peak luminance of the display unit corresponding to the obtained APL, and tone maps the image based on the detected peak luminance and the received metadata.

Description

Display device and its control method

The present invention relates to a display device and a control method thereof.

High Dynamic Range (HDR) content is content that is designed to provide images with a wide dynamic range in order to give a feeling similar to that of humans. However, since a general display device has a limitation in processing an image of a wide dynamic range, a process called tone mapping is required to reproduce HDR content on a general display device. Here, tone mapping refers to a technique for converting an image of HDR content into an image having a limited dynamic range that can be reproduced by a display device. Recently, specifications to maximize the dynamic range of HDR content on display devices have been discussed. However, since only tone mapping based on fixed peak luminance is discussed, the detail characteristics of HDR can be properly adjusted according to the type of display device. There is a problem that cannot be reproduced.

It is an object of the present invention to solve the above and other problems. Another object of the present invention is to provide a display device capable of reproducing image detail of HDR content by performing tone mapping of an image in consideration of not only the physical peak luminance of the display device but also characteristics of an input image and a black level of the display device. It aims to provide.

Another object of the present invention is to provide a display device and a method of controlling the same, which can realize an optimal HDR effect even in a display device having a peak brightness different according to the APL of the input image.

It is still another object of the present invention to provide a display device and a control method capable of variably applying a luminance curve for tone mapping according to characteristics of an input image.

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.

According to an embodiment of the present invention, a display device includes a receiver including a content including an image having a high dynamic range and metadata of the content (the metadata indicates a dynamic range of the image). Information, information representing peak luminance of the image, and information representing luminance curve of the image), and a controller, wherein the controller comprises: an APL (Average Picture) of an image included in the received content; Level), detect peak luminance of the display unit corresponding to the obtained APL, and perform tone mapping of the image based on the detected peak luminance, the received metadata, and the black level of the display unit. do.

According to an aspect of the present invention, there is provided a method of controlling a display device, the method comprising: receiving a content including metadata having an image having a high dynamic range and metadata of the content (the metadata is dynamic of the image); Obtaining at least one of information indicating a range, information indicating a peak luminance of the image, and information representing a luminance curve of the image), and obtaining an average picture level (APL) of an image included in the received content. Detecting a peak luminance of the display unit corresponding to the obtained APL, and performing tone mapping of the image based on the detected peak luminance, the received metadata, and the black level of the display unit. It includes.

The effects of the display device and its control method according to the present invention will be described below.

According to an embodiment of the present invention, it is possible to provide a display device for performing tone mapping of an image in consideration of not only physical peak luminance of the display device but also characteristics of an input image and a black level of the display device, and a method of controlling the same.

According to an embodiment of the present invention, a display device and a method of controlling the same may be provided so that an optimal HDR effect may be implemented even in a display device having different peak luminance according to an APL of an input image.

According to an embodiment of the present invention, a display device and a method of controlling the same may be provided in which a luminance curve for tone mapping is variably applied according to characteristics of an input image.

Further scope of the applicability of the present invention will become apparent from the following detailed description. However, various changes and modifications within the spirit and scope of the present invention can be clearly understood by those skilled in the art, and therefore, specific embodiments, such as the detailed description and the preferred embodiments of the present invention, should be understood as given by way of example only.

FIG. 1 is a diagram schematically illustrating a service system including a display device according to an exemplary embodiment.

2 is a block diagram illustrating a display device according to an embodiment of the present invention.

3 is a block diagram illustrating the detailed configuration of the controller of FIG. 2 according to an embodiment of the present invention.

4 is a diagram illustrating input means connected to the display device of FIG. 2 according to an embodiment of the present invention.

5 is a diagram illustrating luminance curves of a display unit included in a specific display device.

6 is a flowchart illustrating an example of a method of performing tone mapping of an HDR image in a display device according to an embodiment of the present invention.

7 is a diagram illustrating an example of a luminance curve for tone mapping of an image in a display device according to an embodiment of the present invention.

8 is a flowchart illustrating another example of a method of performing tone mapping of an HDR image in a display device according to an embodiment of the present invention.

9 is a diagram illustrating an example of a specific frame constituting an HDR image.

10 is a block diagram illustrating a display device according to an embodiment of the present invention.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings, and the same or similar components are denoted by the same reference numerals regardless of the reference numerals, and redundant description thereof will be omitted. The suffixes "module" and "unit" for components used in the following description are given or used in consideration of ease of specification, and do not have distinct meanings or roles from each other. In addition, in describing the embodiments disclosed herein, when it is determined that the detailed description of the related known technology may obscure the gist of the embodiments disclosed herein, the detailed description thereof will be omitted. In addition, the accompanying drawings are intended to facilitate understanding of the embodiments disclosed herein, but are not limited to the technical spirit disclosed herein by the accompanying drawings, all changes included in the spirit and scope of the present invention. It should be understood to include equivalents and substitutes.

Terms including ordinal numbers such as first and second may be used to describe various components, but the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may be present in between. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

Singular expressions include plural expressions unless the context clearly indicates otherwise.

In this application, the terms "comprises" or "having" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

FIG. 1 is a diagram schematically illustrating a service system including a display device according to an exemplary embodiment.

Referring to FIG. 1, the service system includes a content provider 10, a service provider 20, a network provider 30, and a home network end user (HNED). And 40. Here, the HNED 40 comprises, for example, a client 100, ie a display device according to the invention.

The content provider 10 produces and provides various contents. As shown in FIG. 1, such a content provider 10 may include a terrestrial broadcast sender, a cable SO (System Operator) or MSO (Multiple SO), a satellite broadcast sender, various Internet broadcast senders, and an individual. Content providers and the like. The content provider 10 may produce and provide various services or applications in addition to broadcast content.

The service provider 20 service packetizes the content produced by the content provider 10 and provides it to the HNED 40. For example, the service provider 20 may package at least one or more of contents produced by the first terrestrial broadcast, the second terrestrial broadcast, the cable MSO, the satellite broadcast, the various Internet broadcasts, the application, and the like for the service, and the HNED ( 40).

The service provider 20 provides a service to the client 100 in a uni-cast or multi-cast manner. On the other hand, the service provider 20 may transmit data to a plurality of clients 100 registered in advance, for this purpose may use the Internet Group Management Protocol (IGMP) protocol.

The content provider 10 and the service provider 20 described above may be the same entity. For example, the content produced by the content provider 10 may be packaged as a service and provided to the HNED 40 to perform the functions of the service provider 20 together or vice versa.

The network provider 30 provides a network for data exchange between the content provider 10 or / and the service provider 20 and the client 100.

The client 100, as a consumer belonging to the HNED 40, receives a data through a network provider 30, for example, by establishing a home network, and receives data about various services or applications such as VoD and streaming. You can also send / receive.

Meanwhile, the content provider 10 and / or the service provider 20 in the service system may use conditional access or content protection means to protect the transmitted content. Accordingly, the client 100 may use a processing means such as a cable card (or point of deployment) or a downloadable casing (DCAS) in response to the limited reception or content protection.

In addition, the client 100 may also use a bidirectional service through a network. Accordingly, the client 100 may perform a role or function of a content provider, and the service provider 20 may receive it and transmit it to another client.

In FIG. 1, the content provider 10 and / or the service provider 20 may be a server that provides a service described later herein. In this case, the server may mean owning or including the network provider 30 as necessary. Although not specifically mentioned below, the service or service data includes not only services or applications received from the outside but also internal services or applications, and such services or applications may mean service or application data for the client 100. .

2 is a block diagram illustrating a display device according to an embodiment of the present invention.

Referring to FIG. 2, the display device 200 includes a broadcast receiver 205, an external device interface 235, a storage 240, a user input interface 250, a controller 270, and a display 280. ), An audio output unit 285, a power supply unit 290, and a photographing unit (not shown). Here, the broadcast receiver 205 may include at least one tuner 210, a demodulator 220, and a network interface 230. However, in some cases, the broadcast receiver 205 may include a tuner 210 and a demodulator 220 but may not include the network interface 230 and vice versa. In addition, although not shown, the broadcast receiver 205 includes a multiplexer and a signal demodulated by the demodulator 220 through the tuner 210 and a signal received through the network interface 230. You can also multiplex. In addition, although not shown, the broadcast receiver 225 may include a demultiplexer to demultiplex the multiplexed signal or to demultiplex the demodulated signal or the signal passed through the network interface 230. Can be.

The tuner 210 receives an RF broadcast signal by tuning a channel selected by a user or all previously stored channels among radio frequency (RF) broadcast signals received through an antenna. In addition, the tuner 210 converts the received RF broadcast signal into an intermediate frequency (IF) signal or a baseband signal.

For example, if the received RF broadcast signal is a digital broadcast signal, it is converted into a digital IF signal (DIF). If the analog broadcast signal is converted into an analog baseband video or audio signal (CVBS / SIF). That is, the tuner 210 may process both digital broadcast signals or analog broadcast signals. The analog baseband video or audio signal CVBS / SIF output from the tuner 210 may be directly input to the controller 270.

In addition, the tuner 210 may receive an RF broadcast signal of a single carrier or multiple carriers. Meanwhile, the tuner 210 sequentially tunes and receives RF broadcast signals of all broadcast channels stored through a channel memory function among RF broadcast signals received through an antenna, and then converts them to intermediate frequency signals or baseband signals (DIFs). Frequency or baseband signal).

The demodulator 220 may receive and demodulate the digital IF signal DIF converted by the tuner 210 and perform channel decoding. To this end, the demodulator 220 includes a trellis decoder, a de-interleaver, a reed-solomon decoder, or a convolutional decoder, deinterleaver, and lead. A solo decoder or the like.

The demodulator 220 may output a stream signal TS after performing demodulation and channel decoding. In this case, the stream signal may be a signal multiplexed with a video signal, an audio signal, or a data signal. For example, the stream signal may be an MPEG-2 Transport Stream (TS) multiplexed with an MPEG-2 standard video signal, a Dolby AC-3 standard audio signal, and the like.

The stream signal output from the demodulator 220 may be input to the controller 270. The controller 270 may control demultiplexing, image / audio signal processing, and the like, and control the output of the audio through the display 280 and the audio output unit 285.

The external device interface unit 235 provides an interface environment between the display device 200 and various external devices. To this end, the external device interface unit 235 may include an A / V input / output unit (not shown) or a wireless communication unit (not shown).

The external device interface unit 235 may include a digital versatile disk (DVD), a Blu-ray, a game device, a camera, a camcorder, a computer (laptop), a tablet PC, a smartphone, a Bluetooth device (Bluetooth). device), an external device such as a cloud, etc. may be connected via wired / wireless. The external device interface unit 235 transmits a signal including data such as an image, a video, and an audio input through the connected external device to the controller 470 of the digital device. The controller 270 may control the processed image, video, audio, and the like to output the data signal to the connected external device. To this end, the external device interface unit 435 may further include an A / V input / output unit (not shown) or a wireless communication unit (not shown).

The A / V input / output unit may include a USB terminal, a Composite Video Banking Sync (CVBS) terminal, a component terminal, an S-video terminal (analog), so that video and audio signals of an external device can be input to the display device 200. It may include a DVI (Digital Visual Interface) terminal, HDMI (High Definition Multimedia Interface) terminal, RGB terminal, D-SUB terminal and the like.

The wireless communication unit may perform short range wireless communication with another external device. The display device 200 may include, for example, Bluetooth, Radio Frequency Identification (RFID), Infrared Data Association (IrDA), Ultra Wideband (UWB), ZigBee, and Digital Living Network Alliance (DLNA). It may be networked with other digital devices according to a communication protocol.

In addition, the external device interface unit 235 may be connected to the set top box STB through at least one of the various terminals described above to perform an input / output operation with the set top box STB.

The external device interface unit 235 may receive an application or an application list in a neighboring external device and transmit the received application or application list to the controller 270 or the storage 240.

The network interface unit 230 provides an interface for connecting the display device 200 to a wired / wireless network including an internet network. The network interface unit 230 may include, for example, an Ethernet terminal for connection with a wired network, and for example, a wireless LAN (WLAN) for connection with a wireless network. Fi, Wibro (Wireless broadband), Wimax (World Interoperability for Microwave Access), and High Speed Downlink Packet Access (HSDPA) communication standards.

The network interface unit 230 may transmit or receive data with another user or another external device through the connected network or another network linked to the connected network. In particular, some content data stored in the display device 200 may be transmitted to a user selected from another user or another external device registered in advance to the display device 200 or the selected external device.

Meanwhile, the network interface unit 230 may access a predetermined web page through a connected network or another network linked to the connected network. That is, by accessing a predetermined web page through the network, it is possible to send or receive data with the server. In addition, content or data provided by a content provider or a network operator may be received. That is, content such as a movie, an advertisement, a game, a VOD, a broadcast signal, and related information provided from a content provider or a network provider may be received through a network. In addition, it is possible to receive the update information and the update file of the firmware (firmware) provided by the network operator. It may also transmit data to the Internet or content provider or network operator.

In addition, the network interface unit 230 may select and receive a desired application from among applications that are open through the network.

The storage unit 240 may store a program for processing and controlling each signal in the controller 270, or may store a signal-processed video, audio, or data signal.

In addition, the storage unit 240 may perform a function for temporarily storing an image, audio, or data signal input from the external device interface unit 235 or the network interface unit 230. The storage unit 240 may store information about a predetermined broadcast channel through a channel storage function.

The storage unit 240 may store an application or a list of applications input from the external device interface unit 235 or the network interface unit 230.

In addition, the storage unit 240 may store various platforms described below.

The storage unit 240 may be, for example, a flash memory type, a hard disk type, a multimedia card micro type, a card type memory (for example, SD or XD). Memory, etc.), RAM (RAM), or ROM (EEPROM, etc.) may include at least one type of storage medium. The digital device 400 may reproduce and provide a content file (video file, still image file, music file, document file, application file, etc.) stored in the storage unit 240 to the user.

2 illustrates an embodiment in which the storage unit 440 is provided separately from the control unit 270, but the present invention is not limited thereto. In other words, the storage 240 may be included in the controller 270.

The user input interface unit 250 transmits a signal input by the user to the controller 270 or transmits a signal of the controller 270 to the user.

For example, the user input interface unit 250 controls power on / off, channel selection, screen setting, etc. from the remote control device 400 according to various communication methods such as an RF communication method and an infrared (IR) communication method. The signal may be received and processed, or the control signal of the controller 270 may be transmitted to the remote control device 400.

In addition, the user input interface unit 250 may transmit a control signal input from a local key (not shown) such as a power key, a channel key, a volume key, and a set value to the controller 270.

The user input interface unit 250 may transmit a control signal input from a sensing unit (not shown) that senses a user's gesture to the controller 270 or may sense a signal of the controller 270. (Not shown). Here, the sensing unit may include a touch sensor, a voice sensor, a position sensor, an operation sensor, and the like.

The controller 270 demultiplexes the stream input through the tuner 210, the demodulator 220, or the external device interface unit 235 or processes the demultiplexed signals to generate a signal for video or audio output. And output.

The image signal processed by the controller 270 may be input to the display unit 280 and displayed as an image corresponding to the image signal. In addition, the image signal processed by the controller 270 may be input to the external output device through the external device interface 235.

The audio signal processed by the controller 270 may be audio output to the audio output unit 285. In addition, the voice signal processed by the controller 270 may be input to the external output device through the external device interface 235.

Although not shown in FIG. 2, the controller 270 may include a demultiplexer, an image processor, and the like.

The controller 270 may control the overall operation of the display device 200. For example, the controller 270 may control the tuner 210 to control tuning of an RF broadcast corresponding to a channel selected by a user or a pre-stored channel.

The controller 270 may control the display device 200 by a user command or an internal program input through the user input interface unit 250. In particular, it is possible to connect to the network so that the user can download the desired application or application list into the display device 200.

For example, the controller 270 controls the tuner 210 to input a signal of a selected channel according to a predetermined channel selection command received through the user input interface unit 250. It processes the video, audio or data signal of the selected channel. The controller 270 allows the channel information selected by the user to be output through the display unit 280 or the audio output unit 285 together with the processed video or audio signal.

As another example, the controller 270 may, for example, receive an external device image playback command received through the user input interface unit 250, from an external device input through the external device interface unit 235, for example, a camera or a camcorder. The video signal or the audio signal may be output through the display unit 280 or the audio output unit 285.

The controller 270 may control the display 280 to display an image. For example, a broadcast image input through the tuner 210, an external input image input through the external device interface unit 235, an image input through a network interface unit, or an image stored in the storage unit 240 may be stored. The display unit 280 may control the display. In this case, the image displayed on the display unit 280 may be a still image or a video, and may be a 2D image or a 3D image.

In addition, the controller 270 may control to reproduce the content. In this case, the content may be content stored in the display device 200, received broadcast content, or external input content input from the outside. The content may be at least one of a broadcast image, an external input image, an audio file, a still image, a connected web screen, and a document file.

Meanwhile, when entering an application view item, the controller 270 may control to display an application or a list of applications that can be downloaded from the display device 200 or from an external network.

The controller 270 may control to install and run an application downloaded from an external network along with various user interfaces. In addition, by selecting a user, an image related to an executed application may be controlled to be displayed on the display unit 280.

Although not shown in the drawing, a channel browsing processor may be further provided to generate a thumbnail image corresponding to the channel signal or the external input signal.

The channel browsing processor receives a stream signal TS output from the demodulator 220 or a stream signal output from the external device interface 235, and extracts an image from the input stream signal to generate a thumbnail image. Can be. The generated thumbnail image may be input as it is or encoded to the controller 270. In addition, the generated thumbnail image may be encoded in a stream form and input to the controller 270. The controller 270 may display a thumbnail list including a plurality of thumbnail images on the display unit 280 using the input thumbnail image. Meanwhile, the thumbnail images in the thumbnail list may be updated sequentially or simultaneously. Accordingly, the user can easily grasp the contents of the plurality of broadcast channels.

The display unit 280 converts an image signal, a data signal, an OSD signal processed by the controller 270, or an image signal, data signal, etc. received from the external device interface unit 235 into R, G, and B signals, respectively. Generate a drive signal.

The display unit 280 may be a PDP, an LCD, an OLED, a flexible display, a 3D display, or the like.

The display unit 280 may be configured as a touch screen and used as an input device in addition to the output device.

The audio output unit 285 receives a signal processed by the controller 270, for example, a stereo signal, a 3.1 channel signal, or a 5.1 channel signal, and outputs a voice signal. The voice output unit 285 may be implemented by various types of speakers.

Meanwhile, in order to detect a gesture of a user, as described above, a sensing unit (not shown) including at least one of a touch sensor, a voice sensor, a position sensor, and a motion sensor may be further provided in the display device 200. . The signal detected by the sensing unit (not shown) may be transmitted to the control unit 270 through the user input interface unit 250.

On the other hand, a photographing unit (not shown) for photographing the user may be further provided. Image information photographed by a photographing unit (not shown) may be input to the controller 270.

The controller 270 may detect a user's gesture by combining or respectively combining an image photographed by a photographing unit or a sensed signal from a sensing unit (not shown).

The power supply unit 290 supplies the corresponding power throughout the display device 200.

In particular, power may be supplied to the controller 270, which may be implemented in the form of a System on Chip (SoC), a display unit 280 for displaying an image, and an audio output unit 285 for audio output. Can be.

To this end, the power supply unit 290 may include a converter (not shown) for converting AC power into DC power. Meanwhile, for example, when the display unit 280 is implemented as a liquid crystal panel including a plurality of backlight lamps, an inverter capable of operating a pulse width modulation (PWM) for variable brightness or dimming driving It may further comprise an inverter (not shown).

The remote control device 400 transmits a user input to the user input interface unit 250. To this end, the remote control device 400 may use Bluetooth, RF (Radio Frequency) communication, Infrared (IR) communication, UWB (Ultra Wideband), ZigBee (ZigBee) method and the like.

In addition, the remote control device 400 may receive an image, an audio or a data signal output from the user input interface unit 250, display it on the remote control device 400, or output a voice or vibration.

The display device 200 described above may be a digital broadcast receiver capable of processing a fixed or mobile ATSC or DVB digital broadcast signal.

In addition, the display device according to the present invention may omit some of the configurations of the illustrated configuration, or may further include a configuration that is not illustrated on the contrary. On the other hand, unlike the above-described display device, the display device does not include a tuner and a demodulator, and may receive and play content through a network interface unit or an external device interface unit.

3 is a block diagram illustrating the detailed configuration of the controller of FIG. 2 according to an embodiment of the present invention.

An example of the controller 270 may include a demultiplexer 310, an image processor 320, an OSD generator 340, a mixer 350, and a frame rate converter (FRC) 355. ), And a formatter 360. In addition, although not shown, the controller may further include a voice processor and a data processor.

The demultiplexer 310 demultiplexes an input stream. For example, the demultiplexer 310 may demultiplex the input MPEG-2 TS video, audio, and data signals. Here, the stream signal input to the demultiplexer 310 may be a stream signal output from a tuner, a demodulator, or an external device interface unit.

The image processor 320 performs image processing of the demultiplexed image signal. To this end, the image processor 320 may include an image decoder 325 and a scaler 335.

The video decoder 325 decodes the demultiplexed video signal, and the scaler 335 scales the resolution of the decoded video signal so that the display unit can output the resolution.

The image decoder 325 may support various standards. For example, the video decoder 325 performs a function of the MPEG-2 decoder when the video signal is encoded in the MPEG-2 standard, and the video signal is encoded in the Digital Multimedia Broadcasting (DMB) method or the H.264 standard. In this case, the function of the H.264 decoder can be performed.

On the other hand, the video signal decoded by the video processor 320 is input to the mixer 350.

The OSD generator 340 generates OSD data according to a user input or itself. For example, the OSD generator 340 generates data for displaying various data in a graphic or text form on the screen of the display unit 280 based on a control signal of the user input interface unit. The generated OSD data includes various data such as a user interface screen of the digital device, various menu screens, widgets, icons, viewing rate information, and the like. The OSD generator 340 may generate data for displaying broadcast information based on subtitles or EPGs of a broadcast image.

The mixer 350 mixes the OSD data generated by the OSD generator 340 and the image signal processed by the image processor to provide the formatter 360. Since the decoded video signal and the OSD data are mixed, the OSD is overlaid and displayed on the broadcast video or the external input video.

The frame rate converter (FRC) 355 converts a frame rate of an input video. For example, the frame rate converter 355 may convert the frame rate of the input 60Hz image to have a frame rate of, for example, 120Hz or 240Hz according to the output frequency of the display unit. As described above, various methods may exist in the method of converting the frame rate. For example, when the frame rate converter 355 converts the frame rate from 60 Hz to 120 Hz, the frame rate converter 355 inserts the same first frame between the first frame and the second frame or predicts the first frame from the first frame and the second frame. It can be converted by inserting three frames. As another example, when converting the frame rate from 60Hz to 240Hz, the frame rate converter 355 may insert and convert three more identical or predicted frames between existing frames. On the other hand, when no separate frame conversion is performed, the frame rate converter 355 may be bypassed.

The formatter 360 changes the output of the input frame rate converter 355 to match the output format of the display unit. For example, the formatter 360 may output R, G, and B data signals, and the R, G, and B data signals may be output as low voltage differential signals (LVDS) or mini-LVDS. Can be. In addition, when the output of the input frame rate converter 355 is a 3D video signal, the formatter 360 may support a 3D service through the display by configuring the output in a 3D form according to the output format of the display.

The voice processing unit (not shown) in the controller may perform voice processing of the demultiplexed voice signal. The voice processor (not shown) may support processing of various audio formats. For example, even when a voice signal is encoded in a format such as MPEG-2, MPEG-4, AAC, HE-AAC, AC-3, BSAC, etc., a decoder corresponding thereto may be provided.

Also, the voice processing unit (not shown) in the controller may process base, treble, volume control, and the like.

The data processor in the control unit (not shown) may perform data processing of the demultiplexed data signal. For example, the data processor may decode the demultiplexed data signal even when it is encoded. Here, the encoded data signal may be EPG information including broadcast information such as a start time and an end time of a broadcast program broadcasted in each channel.

On the other hand, the above-described digital device is an example according to the present invention, each component may be integrated, added, or omitted according to the specifications of the digital device actually implemented. That is, as needed, two or more components may be combined into one component or one component may be subdivided into two or more components. In addition, the function performed in each block is for explaining an embodiment of the present invention, the specific operation or device does not limit the scope of the present invention.

The digital device may be an image signal processing device that performs signal processing of an image stored in the device or an input image. As another example of a video signal processing device, a set-top box (STB) excluding the display unit 280 and the audio output unit 285 shown in FIG. 2, the above-described DVD player, Blu-ray player, game device, computer And the like can be further illustrated.

4 is a diagram illustrating input means connected to the display device of FIG. 2 according to an embodiment of the present invention.

In order to control the display device 200, a front panel (not shown) or a control means (input means) provided on the display device 200 may be used.

On the other hand, the control means is a user interface device (UID) capable of wired, wireless communication, the remote control 410, keyboard 430, pointing device 420, mainly implemented for the control purpose of the display device 200, A touch pad may be included, but a control means dedicated to external input connected to the display device 200 may also be included. In addition, the control means includes a mobile device such as a smart phone, a tablet PC, and the like, which control the display device 200 through mode switching or the like, although not the purpose of controlling the display device 200. However, in the present specification, for convenience, a pointing device is described as an embodiment, but is not limited thereto.

The input means is a communication protocol such as Bluetooth, Radio Frequency Identification (RFID), Infrared Data Association (IrDA), Ultra Wideband (UWB), ZigBee, Digital Living Network Alliance (DLNA), RS, or the like. At least one may be employed as necessary to communicate with the digital device.

The remote controller 410 refers to conventional input means equipped with various key buttons necessary for controlling the display device 200.

The pointing device 420 is equipped with a gyro sensor or the like and implements a pointer corresponding to the screen of the display device 200 based on a user's movement, pressure, rotation, and the like, and the display device 200. Transmits a predetermined control command. The pointing device 420 may be named by various names such as a magic remote controller and a magic controller.

The keyboard 430 is an intelligent integrated digital device that provides a variety of services such as a web browser, an application, a social network service (SNS), etc., as the display device 200 not only provides a conventional broadcast but also controls only the conventional remote controller 410. It is not easy to implement, and it is implemented to facilitate input of texts by implementing it similar to the keyboard of a PC.

On the other hand, the control means such as the remote control 410, pointing device 420, keyboard 430 is provided with a touch pad, if necessary, for more convenient and various control purposes, such as text input, pointer movement, enlargement / reduction of pictures and videos Can be used for

Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 5 to 10. In the present specification, it is assumed that at least one of the above-described content provider 10, service provider 20, and network provider 30 provides content including an image having a high dynamic range (HDR). . Dynamic range may include a contrast ratio, and may indicate how large a difference between two colors in an image can be naturally expressed as in the real world. For convenience of description, content including an image having a high dynamic range may be referred to as HDR content, and an image having a high dynamic range may be referred to as an HDR image. Here, the image may be a concept including a video image, a moving image, a still image, a panoramic image, a graphic image, and the like. In addition, as an example, the high dynamic range may mean a dynamic range of 1: 103 or more.

5 is a diagram illustrating luminance curves of a display unit included in a specific display device. Referring to FIG. 5, prior to the present invention, a problem of a method of performing tone mapping of HDR content in a display device will be described.

Fig. 5 shows an example of the APL vs. luminance curve of the display section including the OLED. When the display unit includes an OLED, the display unit may follow a luminance curve in which the peak luminance decreases as the peak current decreases as the APL of the image increases due to the current driving method of the OLED.

Meanwhile, when the HDR content is received, the conventional display device performs tone mapping of an image according to a fixed luminance curve based on the maximum peak luminance physically embodied in the display unit. For example, when the dynamic range of the HDR content is 0.117 to 20,000 nit and the maximum peak luminance physically embodied in the display unit is 100 nit, the display device may set the dynamic range of the HDR content within 100 nit which is the maximum peak luminance of the display unit. Tone mapping is performed by converting to a low dynamic range that can be expressed by. The fixed luminance curve by a preset technique (eg, gamma correction) is applied when the tone mapping is performed. Recently, display devices capable of realizing a brightness of 1000 nit or more according to a product by increasing the maximum peak brightness that can be physically implemented in the display unit have been proposed. However, even in such a display device, HDR content is displayed in a wider dynamic range than in the conventional art. It is possible to perform low tone mapping, but there is a limit to reproduce the detail characteristics of the HDR content.

In particular, in the case of a display device including an OLED, as shown in FIG. 5, even when the peak luminance of the display unit varies according to the APL of the image, the maximum peak luminance that can be physically implemented in the display unit without considering the variability of the peak luminance. When tone mapping of an image is performed according to a fixed luminance curve based on, the image quality of contrast, color, and gradation may be lowered than when the content of a low dynamic range is reproduced.

Accordingly, the present invention provides a display device and a control method thereof capable of reproducing the details of HDR content by performing tone mapping of an image in consideration of not only the physical peak luminance of the display device but also characteristics of an input image and a black level of the display device. I would like to suggest. In particular, in the case of a display device having a characteristic in which the peak luminance is variable according to the APL of the image, the luminance curve for tone mapping of the image is variablely applied based on the variable peak luminance, thereby inputting within a range that can be implemented in the display device. We propose a method that can maximize the HDR characteristics of an image.

6 is a flowchart illustrating an example of a method of performing tone mapping of an HDR image in a display device according to an embodiment of the present invention.

The controller 270 of the display device 200 controls the receiver 205 to receive content including an image having a high dynamic range (HDR) and metadata of the content (S610). Here, the receiver 210 may be a tuner 210 or a network interface 230. According to an embodiment, when the content is received from an external device through the external device interface unit 235, the external device interface unit 235 may serve as the reception unit 205.

The metadata of the content may include at least one of information representing a dynamic range of the image, information representing a peak luminance of the image, and information representing a luminance curve of the image. The luminance curve of the image may be a luminance curve representing a range between a minimum luminance and a maximum luminance according to the APL of the image in order to implement HDR of the content. The content provider 10, the service provider 20, and / or the network provider 30 that provide the content may provide information necessary for processing the HDR image in the display device 200 as metadata of the content. .

The controller 270 obtains an average picture level (APL) of an image included in the received content (S620). The controller 270 may decode an image included in the received content and obtain an APL based on pixel data of the decoded image. The controller 270 may obtain the APL of the image at every preset time or at every preset frame.

The controller 270 detects peak luminance of the display unit 280 corresponding to the obtained APL (S630). The peak luminance refers to the maximum luminance that the display unit 280 can produce. In some embodiments, the peak luminance may be the same as the physical peak luminance that can be implemented in the display unit 280, or the display unit 280. ) May be lower than the physical peak luminance that can be realized. For example, the peak luminance may vary according to the APL of the input image (image), or the peak luminance may be a fixed value regardless of the APL of the input image.

The controller 270 may determine the peak luminance of the display unit 280 based on a preset luminance curve according to the type of the display unit 280. The luminance curve may be dependent on a characteristic based on the type of the display unit 280. Here, the type of the display unit 280 means that the display unit 280 is a cathode ray tube (CRT) and a light emitting diode (LED). It may be determined by any one of an organic light emitting diode (OLED), a plasma display panel (PDP), a quantum dot (QD) display, and a QD LED display. For example, when the display unit 280 includes an OLED, when the APL of the image increases due to the current driving method of the OLED, an instantaneous peak current decreases and a luminance curve of the peak luminance of the display unit 280 decreases. When the display unit 280 includes the LCD, the peak luminance of the display unit 280 may follow a constant luminance curve regardless of the APL of the image due to the voltage driving method of the LCD. The storage unit 240 may store data corresponding to the APL versus luminance curve of the display unit 280. When the display unit 280 includes the OLED, the controller 270 may determine the peak luminance of the display unit 280 based on the luminance curve of FIG. 5 stored in the storage unit 240.

The controller 270 performs tone mapping of the image based on the detected peak luminance of the display unit 280 and metadata of the received content (S540). Tone mapping of an image refers to a process of adjusting at least one of brightness, dynamic range, chromaticity, and saturation of an HDR image included in the received content and converting the image into a dynamic range image that can be implemented by the display device 200. The controller 270 may adjust the tone of the image based on a minimum luminance derived by a preset technique (eg, gamma correction), the peak luminance of the detected display unit 280, and metadata of the received content. Mapping can be performed.

According to an exemplary embodiment, the controller 270 may perform the tone mapping of the image in consideration of the black level of the display unit 280 together with the detected peak luminance of the display unit 280 and metadata of the received content. It can also be done. The black level of the display unit 280 represents the brightness level of the darkest part of the image output through the display unit 280, and may be a preset fixed value according to the type of the display unit 280. The storage unit 240 may store data corresponding to the black level of the display unit 280.

Conventional display devices, when the tone mapping of the image, does not reflect the black level of the display unit, but the minimum brightness derived by a predetermined technique (e.g., gamma correction) and the physical peak luminance that can be implemented in the display unit. Since only a fixed luminance curve based was applied, there was a limit in expressing the contrast of the image to the maximum. However, according to an exemplary embodiment of the present invention, the black level of the display unit 280 is also considered when tone mapping of an image, thereby providing an image that can be realistically represented from a low APL to a high APL.

Specifically, the controller 270 is based on the detected peak brightness of the display unit 280, the metadata of the received content and the black level of the display unit 280, the luminance curve for the tone mapping of the image Can be determined. The controller 270 re-acquires the APL of the image at every preset time or at a predetermined frame, detects the peak luminance of the display unit 280 corresponding to the re-acquired APL, and re-acquires the APL. The determined luminance curve may be varied based on the peak luminance corresponding to the APL, the metadata of the received content, and the black level of the display unit 280. In addition, the controller 270 may process the image and control the luminance of the display unit 280 based on the determined luminance curve.

6 illustrates an example in which the peak luminance of the display unit 280 is changed according to the APL of an image, such as a display device 200 including an OLED, but the embodiment of the present invention according to FIG. In the case of the display device 200 in which the peak luminance of the display unit 280 does not vary according to APL of FIG. That is, in the latter case, the display device 200 according to the preset image quality setting conditions or the image quality setting conditions changed by the user, the physical peak luminance that can be implemented in the display unit 280, the metadata of the received content and The luminance curve for tone mapping of the image may be variablely applied based on the black level of the display unit 280. In this case, since the physical peak luminance that can be implemented in the display unit 280 and the black level of the display unit 280 are fixed values, the minimum luminance value and peak luminance value for each APL of the variable luminance curve are also fixed. Value, and the slope of the luminance curve may vary between the minimum luminance value and the peak luminance value. For example, when a movie dedicated image quality condition is set or a game dedicated image quality condition is set by the user, the controller 270 may vary and apply a luminance curve for tone mapping of an image according to the set image quality condition.

7 is a diagram illustrating an example of a luminance curve for tone mapping of an image in a display device according to an embodiment of the present invention.

The controller 270 may variably apply a luminance curve for tone mapping of the image according to a characteristic (eg, APL) of the image included in the received content. For example, when the peak luminance value of the display unit 280 corresponding to the obtained APL is 5000 nit and the black level of the display unit 280 is 0.1 nit, the controller 270 may have 0.1 nit. When the tone mapping of the image is performed based on the A graph, and the peak luminance value of the display unit 280 corresponding to the obtained APL is 2000 nit and the black level of the display unit 280 is 0.1 nit, the black level is When the tone mapping of the image is performed based on the B graph of 0.1 nit, and the peak luminance value of the display unit 280 corresponding to the obtained APL is 1000 nit and the black level of the display unit 280 is 0.1 nit. Tone mapping of the image may be performed based on a C graph having a black level of 0.1 nit. As another example, when the peak luminance value of the display unit 280 corresponding to the obtained APL is 5000 nit and the black level of the display unit 280 is 0.01 nit, the controller 270 may have a 0.01 nit value. Tone mapping of the image may be performed based on an A graph. Of course, even when the value of the peak luminance of the display unit 280 corresponding to the obtained APL is 5000 nit and the black level of the display unit 280 is equal to 0.1 nit, the obtained APL and the display unit 280 Of course, the slope of the A graph may vary based on the peak luminance, the metadata of the received HDR content, and the black level of the display unit 280.

If the acquired APL is changed according to the image frame during the reproduction of the HDR content, the controller 270 redetects the peak luminance of the display unit 280 corresponding to the changed APL, and accordingly, the tone mapping of the image is performed. The luminance curve can be variably applied.

According to the present embodiment, as the characteristics of the input image (image) change, the user can provide the optimized HDR content by changing the luminance curve for tone mapping of the input image, and display the tone when the tone mapping of the input image is performed. By reflecting the difference in the black level of the unit 280, there is an effect that can reproduce the characteristics of the HDR in more detail.

8 is a flowchart illustrating another example of a method of performing tone mapping of an HDR image in a display device according to an embodiment of the present invention. 5 and 7 will not be described in detail and will be described below based on differences.

The controller 270 of the display device 200 controls the receiver 205 to receive content including an image having a high dynamic range (HDR) and metadata of the content (S810).

The controller 270 obtains an APL for each block of the image included in the received content (S820). The controller 270 may decode an image included in the received content and obtain an APL for each block based on pixel data of the decoded image. The controller 270 may obtain the APL of the image at every preset time or at every preset frame.

9 is a diagram illustrating an example of a specific frame constituting an HDR image.

The controller 270 may divide the frame constituting the image included in the received content into a predetermined number of blocks B and obtain an APL for each block B. For example, the number and size of blocks B for dividing the frame may be determined based on the size of the display unit 280, and may be determined based on the number and size of light emitting blocks of the backlight unit included in the display unit 280. The number may be determined by the number and size of unit light emitting blocks capable of local dimming driving in the backlight unit included in the display unit 280.

Since the image expressed through each block B is different, the APL for each block may have a different value for each block. For example, the value of the APL of the block B1 corresponding to the bright image may be greater than the value of the APL of the block B2 corresponding to the dark image.

Referring back to FIG. 8, the controller 270 detects peak luminance of the display unit 280 corresponding to the obtained APL for each block (S830). That is, the controller 270 may detect a value of the maximum luminance that an area of the display unit 280 corresponding to each block of the image can achieve in relation to the APL of each block of the image. The controller 270 may determine the peak luminance of the display unit 280 based on a preset luminance curve according to the type of the display unit 280.

The controller 270 performs tone mapping of the image for each block based on the peak luminance of the display unit 280 corresponding to the detected block-specific APL and metadata of the received content (S840). ). Since the APLs are different for each block of the image, and thus the peak luminance of the display unit 280 corresponding to the APL is also different, the controller 270 may perform tone mapping of the image for each block.

According to an embodiment, the controller 270 may also consider the black level of the display unit 280 along with the peak luminance of the display unit 280 corresponding to the detected block-specific APL and metadata of the received content. Tone mapping of the image may be performed.

In detail, the controller 270 is configured for each block based on the peak luminance of the display unit 280 corresponding to the detected APL for each block, the metadata of the received content, and the black level of the display unit 280. A luminance curve for tone mapping of the image may be determined. The controller 270 re-acquires the APL for each block of the image at every preset time or at a predetermined frame, and detects the peak luminance of the display unit 280 corresponding to the re-acquired APL for each block. The determined luminance curve may be changed for each block based on the peak luminance corresponding to the re-acquired APL for each block, the metadata of the received content, and the black level of the display unit 280.

A luminance curve for tone mapping of the image is similar to that described above with reference to FIG. 7 except that the luminance curve for each tone mapping of the image is changed, and thus a detailed description thereof will be omitted.

According to the present exemplary embodiment, the luminance curve for tone mapping of the input image is changed by reflecting the block-specific characteristics of the input image (image), so that the display device 200 can reproduce the characteristics of HDR in more detail. There is.

8 illustrates an example in which the peak luminance of the display unit 280 varies according to the APL of the image, such as the display device 200 including the OLED, but the embodiment according to FIG. 8 is illustrated. Of course, may be applied to the case of the display device 200 in which the peak brightness of the display unit 280 does not vary according to the APL of the image.

10 is a block diagram illustrating a display device according to an embodiment of the present invention.

The display device 200 according to an embodiment of the present invention includes a video decoder 1010, a gamut mapping module 1020, a tone mapping module 1030, an APL analysis module 1040, a peak luminance calculation module 1050, and a display. The unit 1060 and the black level analysis module 1070 may be included. According to an embodiment, the video decoder 1010, gamut mapping module 1020, tone mapping module 1030, APL analysis module 1040 and peak luminance calculation module 1050 may be implemented in the control unit 270 of FIG. 2. The display unit 1060 may be implemented as the display unit 280 of FIG. 2, and the black level analysis module 1070 may be implemented in the control unit 270 or the storage unit 240 of FIG. 2.

When an image having HDR and metadata of the image are received from an external server, the image may be input to the video decoder 1010 and the metadata of the HDR image may be input to the tone mapping module 1030.

The video decoder 1010 may decode the image and output the decoded image to the gamut mapping module 1020. In addition, the video decoder 1010 outputs pixel data of the decoded image to the APL analysis module 1040, and the APL analysis module 1040 receives the APL of the image based on the pixel data of the decoded image. Can be obtained. As described above, the APL analysis module 1040 may acquire the APL of the image every preset time or every preset frame, and obtain the APL for each block of the image every preset time or every preset frame. It may be. In addition, the APL analysis module 1040 may output the APL of the obtained image to the peak luminance calculation module 1050.

The peak luminance calculation module 1050 detects the peak luminance of the display unit 1060 corresponding to the APL of the obtained image. The peak luminance calculation module 1050 may detect the peak luminance of the display unit 1060 corresponding to the APL of the obtained image based on a preset APL versus luminance curve according to the type of the display unit 1060. . The peak luminance calculation module 1050 may output the peak luminance of the display unit 1060 corresponding to the APL of the obtained image to the tone mapping module 1030.

Meanwhile, the gamut mapping module 1020 may map a color gamut included in the decoded image to a color gamut that can be expressed by the display unit 1060 and output the result to the tone mapping module 1030. have.

The black level analysis module 1070 may output the black level of the display unit 1060 to the tone mapping module 1030.

The tone mapping module 1030 may include a peak luminance of the display unit 1060 corresponding to the APL of the image input from the peak luminance calculation module 1050, metadata of the received image, and a black level analysis module 1070. The tone mapping of the image may be performed based on the black level of the display unit 1060 input from the image. Since the tone mapping method of the image is similar to that described above with reference to FIGS. 5 to 9, a detailed description thereof will be omitted.

The tone mapping module 1030 may output the tone-mapped image to the display unit 1060, and the display unit 1060 may display an image in which the HDR characteristic is reproduced.

According to the above-described embodiment of the present invention, when the tone mapping of an image is performed by using a luminance curve of a fixed peak luminance in a display device exhibiting a peak luminance varying according to an APL of an input image, a desired HDR effect does not appear. In addition, even in the case of a display device exhibiting a fixed peak luminance regardless of the APL of the input image, a limited device is applied by variably applying a luminance curve for tone mapping of the image by reflecting characteristics of the input image. Despite the characteristics, there is an effect that can implement an excellent contrast ratio.

The present invention described above can be embodied as computer readable codes on a medium in which a program is recorded. The computer-readable medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of computer-readable media include hard disk drives (HDDs), solid state disks (SSDs), silicon disk drives (SDDs), ROMs, RAMs, CD-ROMs, magnetic tapes, floppy disks, optical data storage devices, and the like. This also includes implementations in the form of carrier waves (eg, transmission over the Internet). In addition, the computer may include a control unit of the terminal. Accordingly, the above detailed description should not be construed as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

Modifications may be made by those skilled in the art by referring to the above-described table of contents, "Best Mode for Carrying Out the Invention," in detail.

Since the present invention relates to a display device and a control method thereof, industrial applicability is recognized.

Claims (16)

A receiver including a content including an image having a high dynamic range and metadata of the content, the metadata includes information indicating a dynamic range of the image, information indicating a peak luminance of the image, and At least one of information indicative of a luminance curve of an image; And The control unit, wherein the control unit, Acquires an average picture level (APL) of an image included in the received content, Detecting peak luminance of the display unit corresponding to the obtained APL, And perform tone mapping of the image based on the detected peak brightness and the received metadata. The method of claim 1, And a memory configured to store the black level of the display unit. And the control unit performs tone mapping of the image based on the detected peak luminance, the received metadata, and the black level of the display unit. The method of claim 1, The peak brightness of the display unit corresponding to the APL is determined based on a luminance curve preset according to the type of the display unit. The method of claim 2, The control unit, Re-acquire APL of the image every preset time or every preset frame, Detecting peak luminance of the display unit corresponding to the re-acquired APL, And determine a luminance curve for tone mapping of the image based on the peak luminance corresponding to the re-acquired APL, the received metadata, and the black level of the display unit. The method of claim 2, The control unit, Acquire block-specific APL of the image, Detects peak luminance of the display unit corresponding to the acquired APL for each block, And performing tone mapping of the image for each block based on the peak luminance corresponding to the detected APL for each block, the received metadata, and the black level of the display unit. The method of claim 5, wherein The control unit, Re-acquire APL for each block of the image every preset time or every preset frame, Detecting the peak luminance of the display unit corresponding to the re-acquired APL for each block, And determining, for each block, a luminance curve for tone mapping of the image based on the peak luminance corresponding to the detected APL for each block, the received metadata, and the black level of the display unit. The method of claim 2, The black level of the display unit is a fixed value preset according to the type of the display unit. The method of claim 1, And the tone mapping adjusts at least one of brightness, dynamic range, chroma and saturation of the image. Receiving content including metadata having an image having a high dynamic range and metadata of the content, wherein the metadata includes information representing a dynamic range of the image, information representing a peak luminance of the image, and At least one of information indicative of a luminance curve of an image; Obtaining an average picture level (APL) of an image included in the received content; Detecting peak luminance of the display unit corresponding to the obtained APL; And And performing tone mapping of the image based on the detected peak luminance and the received metadata. The method of claim 9, Acquiring a black level of the display unit from the memory; Tone mapping of the image is performed based on the detected peak brightness, the received metadata, and the black level of the display unit. The method of claim 9, The peak brightness of the display unit corresponding to the APL is determined based on a luminance curve preset according to the type of the display unit. The method of claim 10, APL of the image is reacquired every predetermined time or every predetermined frame, The tone mapping of the image may include determining a luminance curve for tone mapping of the image based on the peak luminance corresponding to the re-acquired APL, the received metadata, and the black level of the display unit. The control method of a display device, including. The method of claim 10, Acquiring an APL of the image includes acquiring an APL for each block of the image, The detecting of the peak luminance includes detecting a peak luminance of the display unit corresponding to the obtained APL for each block, The tone mapping of the image may include performing tone mapping of the image for each block based on the peak luminance corresponding to the detected APL for each block, the received metadata, and the black level of the display unit. And controlling the display device. The method of claim 13, The APL for each block is reacquired every preset time or every preset frame, The tone mapping of the image may be performed for tone mapping of the image for each block based on the peak luminance corresponding to the re-acquired APL for each block, the received metadata, and the black level of the display unit. Determining a brightness curve. The method of claim 9, And a black level of the display unit is a fixed value preset according to the type of the display unit. The method of claim 9, And performing tone mapping of the image, adjusting at least one of brightness, dynamic range, chroma and saturation of the image.

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