CN1703081A - Apparatus and method for receiving image signal - Google Patents

Abstract

Provide a receiving unit (17), configured to selectively receive RGB signals corresponding to VGA and SVGA and XGA, a detection unit (28), configured to detect the type of the received RGB signal, and conversion units (18, 23) , configured to convert the RGB signal according to VGA into a 540p format to be output, and convert the RGB signal according to SVGA and XGA into a 1080i format to be output according to the detection result.

Description

Image signal receiving device and image signal receiving method

technical field

The present invention relates to an image signal receiving device and an image signal receiving method selectively receiving a plurality of types of RGB signals in which the numbers of vertical lines are different from each other and converting them into an image signal according to a format of a display device.

Background technique

As is well known, among recent television receivers, the television receiver has a function of selectively receiving a plurality of types of RGB signals in which the number of vertical lines differs from each other, and converting them into an image signal of a television format to display as an image.

In particular, selectively receiving multiple types of computer graphics formats corresponding to video graphics array (VGA, videographics array) and super video graphics array (SVGA, super video graphics array) or extended graphics array (XGA, extended graphics array) The output RGB signal is converted to an interlaced scan format compatible with a cathode ray tube (CRT) etc. for display as an image.

Japanese Patent Application KOKAI Publication No. 2002-515988 discloses a structure for converting an image signal output from a PC into a scale to perform interlace conversion, a structure for reducing flicker in interlace conversion processing, and the like. Meanwhile, a technology for converting an image signal in a computer graphics format into an image signal in a television format to be displayed as an image is still in the development process, and under the current environment, there is room for further improvement in various aspects.

Contents of the invention

The present invention has been accomplished in consideration of the circumstances described above, and an object of the present invention is to provide an image signal receiving device and an image signal receiving method capable of converting received RGB signals into an image output format set in advance according to the number of vertical lines thereof. A format that can display RGB signals with the highest image quality, preventing deterioration of the vertical resolution.

According to one aspect of the present invention, there is provided an image signal receiving device, comprising: a receiving unit for selectively receiving multiple types of RGB signals in which the numbers of vertical lines are different from each other; a detecting unit for detecting the signal received by the receiving unit the horizontal and vertical frequencies of the RGB signal; and a converting unit for converting the RGB signal received by the receiving unit into a preset image output format to be output-interlaced scanning format and progressive based on the frequency detected by the detecting unit The format with the higher vertical resolution between scan formats.

According to another aspect of the present invention, there is provided an image signal receiving method, comprising: a step of selectively receiving multiple types of RGB signals in which the number of vertical lines is different from each other; a step of detecting the horizontal and vertical frequencies of the received RGB signals ; and based on the detected frequency, converting the received RGB signal into a preset image output format to be output - a format with a higher vertical resolution between the interlaced scanning format and the progressive scanning format.

Description of drawings

FIG. 1 shows an embodiment of the present invention, and is a block diagram for explaining an image signal receiving apparatus;

FIG. 2 is a flowchart for explaining a part of main operations of the image signal receiving apparatus of this embodiment;

FIG. 3 is a flowchart for explaining the remainder of the main operation of the image signal receiving apparatus of this embodiment; and

FIG. 4 shows another example of the present embodiment, and is a block diagram for explaining an image signal receiving device.

Detailed ways

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows an image signal receiving device 11 which will be described in this embodiment. The image signal receiving device 11 has a function of receiving a television broadcast signal, and a function of receiving various types of RGB signals corresponding to VGA and SVGA or XGA.

That is, a television broadcast signal is received by an antenna 12 and supplied to a receiving unit 14 via a television (TV) input terminal 13 . The receiving unit 14 extracts a signal of a predetermined channel from an input television broadcast signal, and outputs it to the selector 15 . In addition, RGB signals supplied from the external PC 16 are supplied to the selector 15 via the input terminal 17 .

The selector 15 selects one of the input dual system image signals to be delivered to the signal processing unit 18 . The signal processing unit 18 applies demodulation processing to the input image signal by the image signal processing unit 19 , and thereafter, applies format conversion processing conforming to the display unit 21 by the output format conversion processing unit 20 at a subsequent stage. Then, the image signal output from the signal processing unit 18 is supplied to a display unit 21 such as a CRT via an image output terminal 22 provided for displaying an image.

Here, in the image signal receiving apparatus 11, all operations thereof, including various receiving operations as described above, are generally controlled by the control unit 23 . The control unit 23 has a central processing unit (CPU) and the like incorporated therein. The control unit 23 receives operation information from the operation unit 24, or receives operation information transmitted from the remote controller 25 via the reception unit 26, and controls each unit so as to reflect the content of the operation.

In this case, the control unit 23 utilizes the storage unit 27 . That is, the storage unit 27 mainly includes a read only memory storing therein a control program executed by the CPU of the control unit 23, a random access memory providing a work area to the CPU, and a nonvolatile memory storing various setting information, control information, and the like. memory.

Here, the image signal selected at the selector 15 is supplied to the detection unit 28 . The detection unit 28 detects horizontal and vertical frequencies, and supplies the detection results to the control unit 23 .

Then, the control unit 23 controls the signal processing unit 18 so as to convert the RGB signals into a format that can display the RGB signals with the highest vertical resolution between formats conforming to the display unit 21 based on the frequency supplied from the detection unit 28 .

Specifically, it is assumed that the display unit 21 conforms to image display in a high definition (HD) format of 1080i (interlace) at a horizontal frequency of 33.75 KHz and a vertical frequency of 60 Hz.

However, it is desirable that since the RGB signal is in the progressive format, it should be displayed as an image in the progressive format without being converted into the interlaced format. That is, in this case, the RGB signal must be converted into a format of 540p (progressive scan) with a horizontal frequency of 33.75 KHz and a vertical frequency of 60 Hz in order to conform the RGB signal to the display unit 21 .

However, assuming that all types of RGB signals corresponding to VGA and SVGA or XGA are simply converted into a format of 540p, in the case of an image signal in a format corresponding to XGA, 768 lines, which are the number of lines in the vertical direction, are converted into 540 lines. Therefore, the sensitivity of the vertical resolution deteriorates, causing small characters and the like to look blurred.

Here, in order to compare those by using a coefficient (Kel coefficient: k=0.7) representing the ratio of the effective vertical resolution, so that the vertical resolution of 1080i is 1080×k=756 lines, and the vertical resolution of 540p is 540 lines . That is, it can be understood that when the image is displayed at 1080i, the sensitivity of the vertical resolution becomes as high as 1.4 times that in the case of displaying the image at 540p, and small character display can be improved. The same applies to RGB signals corresponding to SVGA having 600 vertical lines.

To summarize the above description, when the number of vertical lines of the received RGB signal is less than 540 lines, that is, in the case of an RGB signal corresponding to VGA, the RGB signal is converted into a 540p format to be displayed as an image. When the number of vertical lines of the received RGB signal is greater than or equal to 540 lines, that is, in the case of an RGB signal corresponding to SVGA or XGA, the RGB signal is converted into a 1080i format to be displayed as an image. In this way, RGB signals are displayed on the display unit 21 with the highest vertical resolution.

2 and 3 show flowcharts outlining the above-described operations. That is, the process is started (step S1), and when an RGB signal is received at step S2, the detection unit 28 detects the horizontal and vertical frequencies of the received RGB signal, and at step S3, outputs the detection result to the control unit 23.

Then, in step S4, the control unit 23 determines whether the received RGB signal corresponds to VGA. When it is determined that the RGB signal corresponds to VGA (Yes), the control unit 23 sets various control data required to convert the RGB signal into the 540p format in step S5, and sends the control data to the signal processing unit 18 in step S6. Subsequently, in step S7, the signal processing unit 18 converts the input RGB signal into 540p and 60 Hz to be output to the display unit 21, and ends the processing (step S8).

In addition, when it is determined in the above-mentioned step S4 that the received RGB signal does not correspond to VGA (NO), in step S9, the control unit 23 determines whether the received RGB signal corresponds to SVGA. When it is determined that the RGB signal corresponds to SVGA (Yes), the control unit 23 sets various control data required to convert the RGB signal into the 1080i format in step S10, and sends the control data to the signal processing unit 18 in step S11. Subsequently, in step S12, the signal processing unit 18 converts the input RGB signal into 1080i and 60 Hz to be output to the display unit 21 and ends the processing (step S8).

Furthermore, when it is determined in the above-mentioned step S9 that the received RGB signal does not correspond to SVGA (NO), in step S13, the control unit 23 determines whether the received RGB signal corresponds to XGA. When it is determined that the RGB signal corresponds to XGA (Yes), the control unit 23 sets various control data required to convert the RGB signal into the 1080i format in step S14, and sends the control data to the signal processing unit 18 in step S15. As a result, in step S16, the signal processing unit 18 converts the input RGB signal into 1080i and 60 Hz to be output to the display unit 21 and ends the processing (step S8).

Note that when it is determined in the above-mentioned step 13 that the received signal RGB does not correspond to XGA (No), the control unit 23 determines in step S17 that no RGB signal has been received, and the process ends (step S8).

Figure 4 shows another embodiment of the invention. In FIG. 4, in order to describe the parts identical to those in FIG. 1 with the same symbols, switches 24a and 25a are installed on the operating unit 24 and the remote controller 25, and through these switches, the user switches the received RGB signal into the 1080i format to be displayed as an image, or converted to 540p to be displayed as an image.

That is, in the above-described embodiments, an attempt is made to perform image display at high vertical resolution by converting RGB signals corresponding to SVGA or XGA into the 1080i format. However, in interlaced scanning, there are cases where screen flicker called line flicker occurs and is conspicuous. On the other hand, although line flicker does not occur in the progressive format, the vertical resolution deteriorates compared with the interlaced format.

Then, the present invention is constructed as follows. Through the operations described in FIGS. 2 and 3, for the received RGB signals, format conversion according to the number of vertical lines is performed. Thereafter, the user sees the actual display screen, and switches between the 1080i format and the 540p format by switching the switches 24a and 25a, thereby selecting one format with better image quality than the other format.

Note that the present invention is not limited to the embodiments described above, and structural requirements may be variously modified and embodied within a range not departing from the spirit of the present invention at the stage of realizing the present invention. In addition, various inventions can be formed by appropriately combining a plurality of structural requirements disclosed in the embodiments described above. For example, some structural requirements may be eliminated from all structural requirements shown in this embodiment. Furthermore, structural requirements related to different embodiments may be appropriately combined.

Claims (8)

1. An image signal receiving device, characterized in that, comprising: The receiving unit (17) is configured to selectively receive multiple types of RGB signals with different numbers of vertical lines; a detection unit (28), configured to detect the horizontal and vertical frequencies of the RGB signals received by the receiving unit (17); and The converting unit (18, 23) is configured to convert the RGB signal received by the receiving unit (17) into a preset image output format to be output-interlaced based on the frequency detected by the detecting unit (28) The format with higher vertical resolution between scan format and progressive scan format. 2. The image signal receiving apparatus according to claim 1, wherein: When the pre-set image output format - interlaced scan format and progressive scan format are 1080i and 540p respectively, The conversion unit (18, 23) converts the RGB signal with the number of vertical lines less than 540 lines into the 540p format to be output, and converts the RGB signal with the number of vertical lines greater than or equal to 540 lines into the 1080i format to be output. 3. The image signal receiving apparatus according to claim 1, wherein: Multiple types of RGB signals when the number of vertical lines differ from each other correspond to VGA as well as SVGA and XGA, and Pre-set image output formats - the interlaced and progressive formats are 1080i and 540p respectively, The conversion unit (18, 23) converts RGB signals corresponding to VGA into 540p format to be output, and converts RGB signals corresponding to SVGA and XGA into 1080i format to be output. 4. The image signal receiving device according to claim 1, 2 or 3, further comprising: The operating unit (24a, 25a) is configured to be able to switch whether to convert the RGB signal received by the receiving unit (17) into an interlaced scanning format or a progressive scanning format. 5. A method for receiving an image signal, comprising: Step (17, S2), selectively receiving a plurality of types of RGB signals with different vertical row numbers; Step (28, S3), detecting the horizontal and vertical frequencies of the received RGB signal; and Steps (18, 23, S4 to S16), based on the detected frequency, convert the received RGB signal into a preset image output format to be output - a format with a higher vertical resolution between the interlaced format and the progressive format . 6. image signal receiving method as claimed in claim 5 is characterized in that, When the pre-set image output format - interlaced scan format and progressive scan format are 1080i and 540p respectively, Convert RGB signals with less than 540 vertical lines into 540p format for output, and convert RGB signals with more than or equal to 540 vertical lines into 1080i format for output. 7. image signal receiving method as claimed in claim 5 is characterized in that, When multiple types of RGB signals whose numbers of vertical lines differ from each other correspond to VGA as well as SVGA and XGA, and Pre-set image output formats - the interlaced and progressive formats are 1080i and 540p respectively, Converts RGB signals corresponding to VGA to 540p format to be output, and converts RGB signals corresponding to SVGA and XGA to 1080i format to be output. 8. The image signal receiving method according to claim 5, 6 or 7, further comprising: In step (24a, 25a), switch whether to convert the received RGB signal into an interlaced scanning format or a progressive scanning format through operations.

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