CN116703706A - Blackboard display processing method, device, equipment and storage medium - Google Patents

Abstract

The invention discloses a blackboard writing display processing method, device, equipment and storage medium. Wherein, the method includes the steps of: obtaining the first area position information of the occluder area in the previous image frame and the second area position information of the occluder area in the current image frame; according to the first area position information and the second area position The information determines the third area; obtain the blackboard image and the current image frame; extract the first sub-image at the position of the third area in the blackboard image, and extract the second sub-image at the position of the third area in the current image frame; overlay The first sub-image and the second sub-image to obtain the third sub-image; obtain the previous frame effect image; replace the sub-image at the position of the third area in the previous frame effect image with the third sub-image, and obtain after replacement , and use the replaced image as the effect image of the current frame. The present invention also achieves real-time processing of ultra-high-definition input images, and there will be no situation of playback freeze or frame drop.

Description

Blackboard display processing method, device, equipment and storage medium

technical field

The present invention relates to the technical field of artificial intelligence visual recognition, and more specifically, to a blackboard writing display processing method, device, equipment and storage medium.

Background technique

The blackboard recordings on whiteboards or blackboards used for meetings, speeches, teaching, etc. are important carriers of information transmission. Participants, audiences or students can better understand the information that the speaker wants to convey by watching the blackboard recordings . Therefore, in remote conferences or teaching, videos of blackboard writing are also shot so that participants can watch the speaker’s writing on blackboard. blackboard content.

In the prior art, in order to solve the problem that the blackboard writing content in the video is occluded, an unoccluded blackboard writing image is usually obtained through multi-frame video synthesis, and then the blackboard writing image is superimposed on the current image frame with the speaker to obtain both the speaker and the image frame. The target video frame for clearly reading the contents of the writing on the blackboard. However, the resolution of video is getting higher and higher, which leads to the longer and longer time spent in the superimposition process. For ultra-high-definition input images, it cannot be processed in real time, and playback freezes or frame drops will occur.

Contents of the invention

In order to overcome at least one defect in the prior art, the present invention provides a blackboard writing display processing method, video switching method, device, equipment and storage medium. In order to solve the above-mentioned technical problems, the technical scheme adopted in the present invention is as follows.

In a first aspect, the present invention provides a blackboard display processing method, comprising the steps of:

Obtain the first area position information of the occluder area in the previous image frame and the second area position information of the occluder area in the current image frame, wherein the previous image frame and the current image frame are both captured by the camera image;

determining a third area according to the location information of the first area and the location information of the second area, wherein the scope of the third area includes the first area and the second area;

Obtaining the blackboard image and the current image frame, wherein the blackboard image is an unblocked image about the content of the blackboard;

Extract the first sub-image at the position of the third area in the blackboard image, and extract the second sub-image at the position of the third area in the current image frame;

superimposing the first sub-image and the second sub-image to obtain a third sub-image;

Get the effect image of the last frame;

Using the third sub-image to replace the sub-image at the position of the third area in the previous frame effect image to obtain a replaced image, output the replaced image, and use the replaced image as the current frame effect image.

In one embodiment, further comprising the steps of:

When continuously outputting the replaced image of N frames as the effect image, the latest updated blackboard image is obtained, and the newly updated blackboard image and the N+1th frame image frame are superimposed to obtain an initial effect image, and the initial An effect image, using the initial effect image as the N+1th frame effect image, wherein the N is a preset number threshold, and the N+1th image frame is an image captured by the camera.

In one embodiment, before determining the third area according to the position information of the first area and the position information of the second area, the step further includes:

calculating the coincidence degree between the first area and the second area according to the position information of the first area and the position information of the second area;

When the coincidence degree is within the preset threshold interval, the determining of the third area according to the position information of the first area and the position information of the second area is performed.

In one embodiment, further comprising the steps of:

When the coincidence degree is not within the preset threshold interval, the blackboard image and the current image frame are superimposed to obtain an initial effect image, and the initial effect image is output, and the initial effect image is used as the current frame effect image.

In one embodiment, the location information is a mask image;

The process of determining the third area according to the location information of the first area and the location information of the second area includes the steps of:

A logical OR is performed on the position information of the first area and the position information of the second area to obtain the third area.

In one embodiment, the position information is rectangular coordinate information;

The process of determining the third area according to the location information of the first area and the location information of the second area includes the steps of:

The smallest circumscribed rectangle of the first rectangular area corresponding to the first area position information and the second rectangular area corresponding to the second area position information is taken as the third area.

In an implementation manner, the blackboard writing image is consistent with the blackboard writing image used in generating the last frame of effect image.

In a second aspect, the present invention provides a blackboard writing display processing device, comprising:

The obtaining module is used to obtain the first region position information of the occluder region in the previous image frame and the second region position information of the occluder region in the current image frame, obtain the blackboard image and the current image frame, and obtain the effect of the previous frame image, wherein, the last image frame and the current image frame are images captured by a camera, and the blackboard image is an unblocked image about the content of the blackboard writing;

A determining module, configured to determine a third area according to the location information of the first area and the location information of the second area, wherein the scope of the third area includes the first area and the second area;

Extraction module, for extracting the first sub-image at the position of the third area in the blackboard image, and extracting the second sub-image at the position of the third area in the current image frame;

A superposition module, used to superimpose the first sub-image and the second sub-image to obtain the third sub-image;

A replacement module, configured to replace the sub-image at the position of the third area in the previous frame of the effect image with the third sub-image to obtain a replaced image, output the replaced image, and use the replaced The image of is used as the effect image of the current frame.

In a third aspect, the present invention provides a computer device, including a memory, a processor, and a computer program stored on the memory and operable on the processor, when the processor executes the program, the method of any of the above-mentioned embodiments is implemented .

In a fourth aspect, the present invention provides a computer-readable storage medium on which a computer program is stored, which is characterized in that, when the program is executed by a processor, the method in any one of the above-mentioned implementation modes is implemented.

In the present invention, by acquiring locally changed area position information, image superimposition is only performed on the changed local area, and the corresponding position of the original image is replaced with the superimposed image. Overhead, it can quickly generate superimposed renderings, even for ultra-high-definition input images, it can be processed in real time, and there will be no playback freezes or frame drops.

Description of drawings

Fig. 1 is a schematic flow chart of Embodiment 1 of the present invention.

Fig. 2 is the last image frame of Embodiment 1 of the present invention.

FIG. 3 is a current image frame of Embodiment 1 of the present invention.

Fig. 4 is an image of blackboard writing in Embodiment 1 of the present invention.

Fig. 5 is an effect image of the previous frame according to Embodiment 1 of the present invention.

FIG. 6 is a mask diagram of the last image frame according to Embodiment 1 of the present invention.

Fig. 7 is a mask diagram of the current image frame according to Embodiment 1 of the present invention.

Fig. 8 is the third area of an implementation manner of the first embodiment of the present invention.

FIG. 9 is a rectangular area of the previous image frame according to Embodiment 1 of the present invention.

Fig. 10 is a rectangular area of the current image frame according to Embodiment 1 of the present invention.

Fig. 11 is the third area of another embodiment of the first embodiment of the present invention.

Fig. 12 is the first sub-area of the blackboard writing image in an implementation manner of the first embodiment of the present invention.

Fig. 13 is a second sub-area of the current image frame in an implementation manner of the first embodiment of the present invention.

Fig. 14 is the first sub-area of the blackboard writing image according to another implementation of the first embodiment of the present invention.

Fig. 15 is another implementation manner of the first embodiment of the present invention, the second sub-region of the current image frame.

Fig. 16 is the third sub-area of an implementation manner of the first embodiment of the present invention.

Fig. 17 is the third sub-area of another embodiment of the first embodiment of the present invention.

Fig. 18 is an effect image of the current frame according to Embodiment 1 of the present invention.

Fig. 19 is a schematic diagram of the overall structure of Embodiment 2 of the present invention.

Detailed ways

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided for more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

It should be noted that the term "first\second\..." involved in the embodiment of the present invention is only to distinguish similar objects, and does not represent a specific ordering of objects. Understandably, "first\second\ ..." are interchangeable in specific order or sequence where permissible. It should be understood that "first\second\..." distinctions are interchangeable under appropriate circumstances such that the embodiments of the invention described herein can be practiced in sequences other than those illustrated or described herein.

Embodiment one

Please refer to FIG. 1. FIG. 1 is a schematic flowchart of a blackboard writing display processing method provided by Embodiment 1 of the present invention. The method includes: step S110, step S120, step S130, step S140, step S150, step S160 and step S170. It should be noted that steps S110 to S170 are only reference numerals, which are used to clearly explain the corresponding relationship between the embodiment and FIG. 1 , and do not represent a limitation on the order of the method steps in this embodiment.

Step S110, acquiring the first area position information of the occluder area in the previous image frame and the second area position information of the occluder area in the current image frame, wherein both the previous image frame and the current image frame are camera captured images;

Step S120, determining a third area according to the location information of the first area and the location information of the second area, wherein the scope of the third area includes the first area and the second area;

Step S130, acquiring the blackboard image and the current image frame, wherein the blackboard image is an unobstructed image about the contents of the blackboard;

Step S140, extracting the first sub-image at the position of the third area in the blackboard image, and extracting the second sub-image at the position of the third area in the current image frame;

Step S150, superimposing the first sub-image and the second sub-image to obtain a third sub-image;

Step S160, acquiring the effect image of the last frame;

Step S170, using the third sub-image to replace the sub-image at the position of the third area in the previous frame of the effect image to obtain a replaced image, output the replaced image, and use the replaced image As the current frame effect image.

As shown in FIG. 2 , FIG. 2 is the last image frame captured by the camera, and FIG. 3 is the current image frame captured by the camera. Figure 4 is an unoccluded blackboard writing image obtained by extracting handwriting on the blackboard through multi-frame video synthesis. Figure 5 is the previous frame effect image obtained by superimposing the blackboard image and the previous image frame. The effect image contains both The teacher also includes the blackboard image. It can be understood that this method can be used in various scenarios where blackboard writing can be displayed, and blackboard display boards can be but not limited to blackboards, whiteboards, multimedia display boards, and smart blackboards. However, for the convenience of description, this implementation mode takes a classroom teaching scene as an example for illustration, wherein the blackboard display board is a blackboard, and the content on the blackboard is the blackboard writing content written by the teacher.

What needs to be explained here is that the image frame captured by the camera can be as shown in Figure 3, and its size is similar to the size of the blackboard image, or it can be much larger than the blackboard image, that is, the blackboard area is only a part of the image frame. The effect image of is an image superimposed in some areas, that is, an image generated by superimposing the blackboard writing image on the position of the blackboard writing area in the image frame.

What needs to be explained here is that the image superposition and fusion mainly refers to the transparency superposition of the complete blackboard content image and the captured image frame, including the following two types:

1. It can be alpha linear superposition, O_t=alpha*I_t+(1-alpha)*K_t, where O_t is the effect image, I_t is the captured image frame data, and K_t is the complete blackboard content image;

2. It can be handwriting content replacement: non-blackboard content area: O_t=alpha*I_t, blackboard content area: O_t=K_t. Highlight the content information of blackboard writing by reducing the transparency of non-blackboard writing content areas;

In step S110, the first area position information of the obstruction area in the last image frame and the second area position information of the obstruction area in the current image frame are acquired. In the classroom scene, the occluder is generally the teacher's body, of course, it may also be teaching aids or objects in the hands of the teacher. In addition, the picture captured by the camera is a fixed-focus picture, and the camera will not rotate when shooting, so the camera shoots The content of the screen is basically unchanged, and only when the teacher is moving, the position of the first area and the second area will change.

After obtaining the location information of the first area and the location information of the second area, a third area may be determined according to the location information of the first area and the location information of the second area, where the third area includes the first area and the second area. The third area is actually the area where the picture has changed between the previous video frame and the current video frame.

In one implementation manner, as shown in FIGS. 6 and 7 , the area location information is a mask map. FIG. 6 is the first position information of the occluder region in the last image frame, and FIG. 7 is the second position information of the occluder region in the current image frame.

Wherein, the process of step S120 includes: step S121.

In step S121, a logical OR is performed on the location information of the first area and the location information of the second area to obtain a third area.

As shown in FIG. 8 , the white part in FIG. 8 is the third area obtained by logically ORing the position information of the first area and the position information of the second area.

This embodiment can find out the area that needs to be replaced more accurately, but the computing power will increase.

In one implementation manner, as shown in FIGS. 9 and 10 , the area location information is rectangular coordinate information. The dotted line frame in Fig. 9 is the first rectangular area corresponding to the rectangular coordinate information of the occluder area in the last image frame, and the dotted line frame in Fig. 10 is the second rectangular area corresponding to the rectangular coordinate information of the occluder area in the current image frame. rectangular area.

Wherein, the process of step S120 includes: step S122.

Step S122, taking the smallest circumscribed rectangle of the first rectangular area corresponding to the first area position information and the second rectangular area corresponding to the second area position information as the third area.

As shown in FIG. 11 , the dotted frame in the figure is the smallest circumscribed rectangle of the first rectangular area and the second rectangular area, that is, the third area.

Step S130 acquires the blackboard image shown in FIG. 4 and the current image frame shown in FIG. 3 .

It should be pointed out here that, for the blackboard writing image acquired in step S130, the extraction and update of the complete blackboard writing image are divided into two situations:

1. External direct input of images that record the content of the complete blackboard writing, for example, handwriting written on the electronic screen, you can obtain the complete blackboard writing content by directly obtaining the output of the current electronic screen, and replace the last one with the new blackboard writing content every time The blackboard content image;

2. Update the generated complete blackboard content image according to the previous frame image. First, extract the content of the first frame of blackboard writing, remove the target occluder through the target detection structure, and supplement it with the pixel value of the same color as the background color of the blackboard writing to obtain the initial complete content of the blackboard writing; then, in the next update, obtain the target occluder through target detection Replace the target occluder area of the extracted content of the current frame with the corresponding area content of the last complete blackboard content, and output the extracted content of the current frame as a new complete blackboard content image.

It should also be pointed out here that since the blackboard writing image will be updated, the blackboard writing image used in the previous frame of effect image or the latest updated blackboard writing image can be selected when acquiring the blackboard writing image in step S130. It is preferred here to choose to obtain the blackboard image used in the previous frame of effect image, so that the effect will be better.

In step S140, the blackboard image and the sub-image at the position of the third area in the current image frame are respectively extracted. If the third area is as shown in Figure 8, then as shown in Figure 12 about the first sub-area of the blackboard image, then as shown in Figure 13 about the second sub-area of the current image frame; if the third area is as shown in Figure 13 If it is shown in FIG. 11 , then the first sub-region of the blackboard image is as shown in FIG. 14 , and the second sub-region of the current image frame is as shown in FIG. 15 .

In step S150, the two sub-images are superimposed to obtain a third sub-image. FIG. 12 and FIG. 13 superimpose the third sub-image as shown in FIG. 16 , and FIG. 14 and FIG. 15 superimpose the third sub-image as shown in FIG. 17 .

Then obtain the last frame of effect image, replace the third sub-image with the sub-image at the third area position in the last frame of effect image, obtain the replaced image, as shown in Figure 18, output the replaced image, use The replaced image is used as the effect image of the current frame.

What needs to be explained here is that the current frame effect image obtained by this method will become the previous frame effect image at the next moment, so the previous frame effect image obtained in step S160 may be the type shown in Figure 5, that is, through The blackboard image and image frame are directly superimposed, or it may be the type shown in Figure 18 by replacing some sub-images.

In this method, by obtaining the location information of the locally changed area, only the image superposition is performed on the changed local area, and the corresponding position of the original image is replaced with the superimposed image. Overhead, it can quickly generate superimposed renderings, even for ultra-high-definition input images, it can be processed in real time, and there will be no playback freezes or frame drops.

In one implementation manner, it further includes: step S180.

Step S180, when continuously outputting the replaced image of N frames as the effect image, obtain the latest updated blackboard image, superimpose the latest updated blackboard image and the N+1th image frame to obtain an initial effect image, and output For the initial effect image, use the initial effect image as the N+1th frame effect image, wherein the N is a preset number threshold, and the N+1th image frame is an image captured by the camera.

In the process of replacing part of the sub-image to generate the effect image, there will be errors. These errors may be accumulated in the subsequent effect image, causing the superimposed effect to gradually deteriorate. Therefore, when many consecutive frames are generated by replacing part of the sub-image After the image, it is necessary to "reset" the effect image, that is, set a threshold N, and when the partially superimposed image exceeds the number of connected N frames, the effect image (that is, the initial effect image) is generated by directly superimposing the blackboard image and the image frame. Use this initial effect image as output. In order to ensure that the content of the writing on the blackboard in the initial effect image is up-to-date, the writing on the blackboard image used for superimposition should be the latest updated blackboard writing image.

What needs to be explained here is that if step S130 chooses to acquire the blackboard image used in the previous frame of effect image, N is preferably the interval threshold for refreshing the content of the blackboard image, which can ensure that the blackboard image that has just been updated in real time is used every time The initial effect image is generated, so that the blackboard display processing speed reaches real-time speed.

In one implementation manner, before step S120, further include: step S210.

Step S210, calculating the coincidence degree of the first area and the second area according to the position information of the first area and the position information of the second area;

When the coincidence degree is within the preset threshold interval, step S120 is executed.

In one implementation manner, it further includes: Step S220.

Step S220, when the coincidence degree is not within the preset threshold interval, superimpose the blackboard writing image and the current image frame to obtain an initial effect image, output the initial effect image, and use the initial effect image as the current frame effect image.

Both of the above two implementations add the calculation of coincidence degree, through which it can be seen whether there is a large area change in the area in the two frames of image frames captured by the camera. If the calculated coincidence degree is within the preset threshold range, it means that there is no large area change in the image, which means that the method of using local replacement to obtain the effect image is still appropriate. If the calculated coincidence degree is not within the preset threshold range, It shows that there have been changes in a large area. At this time, it is not suitable to use the method of partial replacement to obtain the effect image. It is necessary to directly superimpose the image on the blackboard and the image frame to generate the effect image.

Embodiment two

Corresponding to the blackboard writing display processing method in Embodiment 1, as shown in FIG. 19 , the present invention also provides a blackboard writing display processing device 19, including: an acquisition module 191, a determination module 192, an extraction module 193, a superposition module 194 and a replacement module 195.

The acquiring module 191 is configured to acquire the first area position information of the occluder area in the previous image frame and the second area position information of the occluder area in the current image frame, acquire the blackboard image and the current image frame, and acquire the previous frame Effect image, wherein, the last image frame and the current image frame are images captured by a camera, and the blackboard image is an unblocked image about the blackboard content;

A determining module 192, configured to determine a third area according to the location information of the first area and the location information of the second area, wherein the range of the third area includes the first area and the second area;

The extraction module 193 is used to extract the first sub-image at the position of the third area in the blackboard image, and extract the second sub-image at the position of the third area in the current image frame;

A superposition module 194, configured to superimpose the first sub-image and the second sub-image to obtain a third sub-image;

The replacement module 195 is used to replace the sub-image at the position of the third area in the effect image of the previous frame with the third sub-image to obtain a replaced image, output the replaced image, and use the replaced The final image is used as the effect image of the current frame.

In this device, by acquiring the location information of the locally changed area, only the changed local area is image superimposed, and the corresponding position of the original image is replaced with the superimposed image. Overhead, it can quickly generate superimposed renderings, even for ultra-high-definition input images, it can be processed in real time, and there will be no playback freezes or frame drops.

In one embodiment, the overlay module is further configured to obtain the latest updated blackboard image when continuously outputting N frames of the replaced image as the effect image, and superimpose the latest updated blackboard image with the current image frame , to obtain an initial effect image, output the initial effect image, and use the initial effect image as the N+1th frame effect image, wherein the N is a preset number threshold, and the N+1th frame image frame is all images captured by the camera.

In one embodiment, a judging module is also included.

The judgment module is used to calculate the coincidence degree of the first region and the second region according to the position information of the first region and the position information of the second region, and when the degree of coincidence is within a preset threshold interval, the control determination module executes the The first area location information and the second area location information determine the third area.

In one embodiment, the judging module is further configured to control the superimposing module to superimpose the blackboard writing image and the current image frame to obtain an initial effect image, and output the initial effect image when the coincidence degree is not within the preset threshold interval. The above initial effect image is used as the current frame effect image.

In one embodiment, the location information is a mask image; the determination module executes the process of determining the third area according to the location information of the first area and the location information of the second area, including steps:

A logical OR is performed on the position information of the first area and the position information of the second area to obtain the third area.

In one embodiment, the location information is rectangular coordinate information; the determination module executes the process of determining the third area according to the location information of the first area and the location information of the second area, including steps:

The smallest circumscribed rectangle of the first rectangular area corresponding to the first area position information and the second rectangular area corresponding to the second area position information is taken as the third area.

In one embodiment, the blackboard image acquired by the acquisition module is consistent with the blackboard image used in generating the last frame of effect image.

Embodiment Three

An embodiment of the present invention also provides a storage medium on which computer instructions are stored, and when the instructions are executed by a processor, the blackboard writing display processing method in any of the above embodiments is implemented.

Those skilled in the art can understand that all or part of the steps for realizing the above-mentioned method embodiments can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, the Including the steps of the foregoing method embodiment; and the aforementioned storage medium includes: various A medium on which program code can be stored.

Alternatively, if the above-mentioned integrated units of the present invention are implemented in the form of software function modules and sold or used as independent products, they can also be stored in a computer-readable storage medium. Based on this understanding, the essence of the technical solution of the embodiment of the present invention or the part that contributes to the related technology can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions to enable A computer device (which may be a personal computer, a terminal, or a network device, etc.) executes all or part of the methods in various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program codes such as removable storage devices, RAM, ROM, magnetic disks or optical disks.

Corresponding to the above-mentioned computer storage medium, in one embodiment, a computer device is also provided, the computer device includes a memory, an encoder, and a computer program stored in the memory and operable on the encoder, wherein the encoder When the program is executed, any blackboard writing display processing method in the above-mentioned embodiments is implemented.

The above-mentioned computer equipment only performs image superimposition on the changed local area by acquiring the position information of the locally changed area, and replaces the corresponding position of the original image with the superimposed image. Overhead, it can quickly generate superimposed effect images, even for ultra-high-definition input images, it can be processed in real time, and there will be no playback freezes or frame drops.

The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, should be considered as within the scope of this specification.

Apparently, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, rather than limiting the implementation of the present invention. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. All modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the claims of the present invention.

Claims (10)

1. The board book display processing method is characterized by comprising the following steps:

acquiring first area position information of a shielding object area in a previous image frame and second area position information of a shielding object area in a current image frame, wherein the previous image frame and the current image frame are images shot by the same camera;

determining a third area according to the first area position information and the second area position information, wherein the range of the third area comprises the first area and the second area;

acquiring an blackboard-writing image and a current image frame, wherein the blackboard-writing image is a non-shielding image related to blackboard-writing content;

extracting a first sub-image at the position of a third area in the blackboard-writing image, and extracting a second sub-image at the position of the third area in the current image frame;

overlapping the first sub-image and the second sub-image to obtain a third sub-image;

acquiring an effect image of the previous frame;

and replacing the sub-image in the position of the third area in the previous frame effect image with the third sub-image to obtain a replaced image, outputting the replaced image, and taking the replaced image as the current frame effect image.

2. The blackboard writing display processing method according to claim 1, characterized by further comprising the steps of:

and when continuously outputting N frames of the replaced images as effect images, acquiring a latest updated blackboard-writing image, superposing the latest updated blackboard-writing image and the N+1th frame of image frames to obtain an initial effect image, outputting the initial effect image, and using the initial effect image as the N+1th frame of effect image, wherein N is a preset quantity threshold value, and the N+1th frame of image frames are images shot by the camera.

3. The blackboard writing display processing method according to claim 1, characterized in that before the third area is determined based on the first area position information and the second area position information, further comprising the steps of:

calculating the coincidence ratio of the first area and the second area according to the first area position information and the second area position information;

and when the overlap ratio is within a preset threshold value interval, executing the third area determination according to the first area position information and the second area position information.

4. The blackboard writing display processing method according to claim 3, characterized by further comprising the step of:

and when the overlap ratio is not within a preset threshold value interval, superposing the blackboard-writing image and the current image frame to obtain an initial effect image, outputting the initial effect image, and taking the initial effect image as the current frame effect image.

5. The blackboard writing display processing method according to any one of claims 1 to 4, characterized in that the position information is a mask map;

the process of determining the third area according to the first area position information and the second area position information comprises the following steps:

and carrying out logical OR on the first area position information and the second area position information to obtain a third area.

6. The blackboard writing display processing method according to any one of claims 1 to 4, characterized in that the position information is rectangular coordinate information;

the process of determining the third area according to the first area position information and the second area position information comprises the following steps:

and taking the minimum circumscribed rectangle of the first rectangular area corresponding to the first area position information and the second rectangular area corresponding to the second area position information as a third area.

7. The method according to claim 1, wherein the board image coincides with a board image used in generating the last frame effect image.

8. An apparatus for displaying and processing a board book, comprising:

the device comprises an acquisition module, a storage module and a display module, wherein the acquisition module is used for acquiring first area position information of a shielding object area in a previous image frame and second area position information of a shielding object area in a current image frame, acquiring an blackboard-writing image and the current image frame, and acquiring a previous frame effect image, wherein the previous image frame and the current image frame are images shot by a camera, and the blackboard-writing image is an unoccluded image related to blackboard-writing content;

the determining module is used for determining a third area according to the first area position information and the second area position information, wherein the range of the third area comprises the first area and the second area;

the extraction module is used for extracting a first sub-image at the position of the third area in the blackboard-writing image and extracting a second sub-image at the position of the third area in the current image frame;

the superposition module is used for superposing the first sub-image and the second sub-image to obtain a third sub-image;

and the replacing module is used for replacing the sub-image in the position of the third area in the previous frame effect image with the third sub-image to obtain a replaced image, outputting the replaced image, and taking the replaced image as the current frame effect image.

9. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor implements the method of any of claims 1-7 when the program is executed by the processor.

10. A computer readable storage medium, on which a computer program is stored, characterized in that the program, when being executed by a processor, implements the method according to any of claims 1-7.