Blackboard-writing area picture switching method and device and blackboard-writing picture switching method and device

Abstract

The invention discloses a switching method of a blackboard-writing area picture and a switching method and device of a blackboard-writing picture. The blackboard-writing area picture switching method comprises the following steps: periodically receiving a blackboard-writing area picture and a blackboard-writing variation corresponding to the blackboard-writing area picture; when a blackboard-writing picture switching instruction is received, identifying all characters in the latest received blackboard-writing area picture, and calculating an arithmetic mean value of the character heights of the latest received blackboard-writing area picture; judging whether the average word height of the newly received blackboard-writing area picture is greater than or equal to a preset word height threshold value or not, and if yes, switching the output picture to the newly received blackboard-writing area picture; and if not, performing clipping and magnifying operation on the newly received blackboard-writing area picture. According to the method, highlighted display of key contents can be realized on the premise of ensuring the watching effect, and the visibility and transmission efficiency of multimedia blackboard writing in the teaching process are effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of visual analysis, and more particularly, to a blackboard region picture switching method and a blackboard picture switching method, device, equipment and storage medium. BACKGROUND

[0002] Blackboard is a core component of classroom teaching. In addition, in meetings, speeches, training and other occasions, real-time writing records on whiteboards or blackboards are also key carriers of information transmission. By watching these blackboard records, participants, audience or students can more clearly grasp the logic and core content of the speaker. Therefore, in remote meetings or teaching, the video of the blackboard is also shot, and the blackboard is further processed, such as presenting the blackboard picture in the video, saving and organizing the blackboard picture, etc.

[0003] With the continuous deepening of education informatization construction, multimedia display screens have become a standard configuration in modern classrooms, especially in large space and multi-blackboard teaching environments, for real-time projection of blackboard content to improve the viewing experience of students in the back rows. However, when shooting panoramic pictures of multiple blackboards, the content of the blackboard is too small in size, resulting in a significant decrease in clarity and readability, which affects the actual viewing effect. SUMMARY

[0004] To overcome at least one of the above-mentioned defects of the prior art, the present application provides a blackboard region picture switching method, a blackboard picture switching method, device, equipment and storage medium. The technical solution adopted by the present application is as follows.

[0005] In a first aspect, the present application provides a blackboard region picture switching method, characterized in that it comprises:

[0006] Periodically receiving a blackboard region picture and a blackboard change amount corresponding to the blackboard region picture; wherein the blackboard change amount is derived based on the amount of writing between the latest received blackboard region picture and the currently output blackboard region picture;

[0007] Upon receiving a blackboard picture switching instruction, identifying all the text in the latest received blackboard region picture and calculating the arithmetic mean of the font height of the latest received blackboard region picture;

[0008] Determining whether the average font height of the latest received blackboard region picture is greater than or equal to a preset font height threshold, and if so, switching the output picture to the latest received blackboard region picture;

[0009] If not, performing a cropping and enlarging operation on the latest received blackboard region picture;

[0010] The cropping and enlarging operation includes:

[0011] S1. Dividing the original board writing area picture into several sub-areas with the same aspect ratio as that of the original board writing area picture according to a preset rule;

[0012] S2. Taking the sub-area with the largest board writing change as a candidate sub-area picture;

[0013] S3. Enlarging the candidate sub-area picture to the same size as the original board writing area picture to obtain a candidate area picture;

[0014] S4. Judging whether the average character height of the candidate area picture is greater than or equal to a preset character height threshold, and if yes, switching the output picture to the candidate area picture;

[0015] S5. If no, performing S1, S2 and S3 on the candidate area again until the average character height of the candidate area picture is greater than or equal to the preset character height threshold, and switching the output picture to the candidate area picture with the average character height greater than or equal to the preset character height threshold.

[0016] In an embodiment, the switching method of the board writing area picture further comprises:

[0017] After the picture switching, entering a locking state within a preset time period, wherein in the locking state, new board writing picture switching instructions are stopped from being received.

[0018] In an embodiment, the preset rule comprises:

[0019] The upper left, upper right, lower left and lower right positions of the original board writing area picture are respectively intercepted to obtain a sub-area with the same aspect ratio as that of the original board writing area picture, and the ratio of the length and width of the sub-area to the length and width of the original board writing area picture is equal to a preset proportion coefficient.

[0020] In an embodiment, the preset rule comprises:

[0021] The upper left, upper middle, upper right, left middle, middle middle, right middle, lower left, lower middle and lower right positions of the original board writing area picture are respectively intercepted to obtain a sub-area with the same aspect ratio as that of the original board writing area picture, and the ratio of the length and width of the sub-area to the length and width of the original board writing area picture is equal to a preset proportion coefficient.

[0022] In an embodiment, the preset rule comprises:

[0023] In the original target area, N regions with the highest writing amount are framed as sub-areas; wherein N is a preset number of sub-areas, the framed sub-areas have the same aspect ratio as that of the original board writing area picture, and the ratio of the length and width of the framed sub-areas to the length and width of the original board writing area picture is equal to a preset proportion coefficient.

[0024] In a second aspect, the present application provides a switching method for a board drawing picture, comprising:

[0025] periodically receiving a board drawing picture, wherein the board drawing picture is divided into a plurality of board region pictures;

[0026] calculating a board change amount of each board region picture, wherein the board change amount is obtained based on a writing amount between a newly received board region picture and a currently output board region picture;

[0027] generating a board picture switching instruction for a board region picture with the largest board change amount, wherein the board picture switching instruction is used to instruct to execute the switching method for the board region picture according to any one of the preceding embodiments.

[0028] In a third aspect, the present application provides a switching device for a board region picture, comprising:

[0029] a receiving module, configured to periodically receive a board region picture and a board change amount corresponding to the board region picture, wherein the board change amount is obtained based on a writing amount between a newly received board region picture and a currently output board region picture;

[0030] a calculating module, configured to, when receiving a board picture switching instruction, identify all characters in the newly received board region picture and calculate an arithmetic mean of character heights of the newly received board region picture;

[0031] an executing module, configured to judge whether the arithmetic mean of the character heights of the newly received board region picture is greater than or equal to a preset character height threshold, and if yes, switch an output picture to the newly received board region picture;

[0032] if no, perform a cropping and enlarging operation on the newly received board region picture;

[0033] wherein the cropping and enlarging operation comprises:

[0034] S1. dividing a plurality of sub-regions with the same aspect ratio as that of the original board region picture in the original board region picture according to a preset rule;

[0035] S2. taking a sub-region with the largest board change amount as a candidate sub-region picture;

[0036] S3. enlarging the candidate sub-region picture to the same size as that of the original board region picture to obtain a candidate region picture;

[0037] S4. judging whether an arithmetic mean of character heights of the candidate region picture is greater than or equal to a preset character height threshold, and if yes, switching the output picture to the candidate region picture;

[0038] S5. If no, re-perform S1, S2 and S3 on the candidate region until the average character height of the candidate region picture is greater than or equal to the preset character height threshold, and switch the output picture to the candidate region picture with the average character height greater than or equal to the preset character height threshold.

[0039] In a fourth aspect, the present application provides a switching device for a board writing picture, characterized in comprising:

[0040] an acquisition module configured to periodically receive a board writing picture, wherein the board writing picture is divided into a plurality of board writing region pictures;

[0041] a variable calculation module configured to calculate a board writing variable of each board writing region picture, wherein the board writing variable is derived based on a writing amount between a latest received board writing region picture and a currently output board writing region picture;

[0042] a generation module configured to generate a board writing picture switching instruction for a board writing region picture with the largest board writing variable, wherein the board writing picture switching instruction is used to instruct to operate the switching device for the corresponding board writing region picture as described above.

[0043] In a fifth aspect, the present application provides a computer device, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method of any of the above embodiments.

[0044] In a sixth aspect, the present application provides a computer readable storage medium, which stores a computer program, wherein the program is executed by a processor to implement the method of any of the above embodiments.

[0045] In the present application, the board writing region is divided into a plurality of small board writing regions, and only one of the board writing regions is switched at a time, thereby simplifying the process of board writing switching. When the board writing region picture needs to be switched, whether the picture is clear and appropriate is determined by the character height, and the switching is implemented only when the picture is clear and appropriate. When the picture is not appropriate, the picture to be switched is cropped and enlarged according to certain rules, so that the picture is clear and appropriate, and the switching is completed after the best display region is obtained. The present application can highlight the key content under the premise of ensuring the viewing effect, and effectively improve the visibility and transmission efficiency of multimedia board writing in the teaching process. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 is a schematic diagram of the whole process of an embodiment of the present application.

[0047] Figure 2 is a schematic diagram of a preset rule of an embodiment of the present application.

[0048] Figure 3 is a picture schematic diagram of a picture containing an entire board picture according to an embodiment two of the present application.

[0049] Figure 4 is a schematic diagram of an overall structure according to an embodiment three of the present application. DETAILED DESCRIPTION

[0050] Exemplary embodiments of the present disclosure will be described hereinafter with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it is understood that the present disclosure can be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0051] It should be noted that the terms "first", "second", and the like in the embodiments of the present application are merely used to distinguish similar objects, and do not represent a specific order of the objects. Understandably, the specific order or sequence of "first", "second", and the like can be interchanged as allowed. It should be understood that the objects distinguished by "first", "second", and the like can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0052] Embodiment one

[0053] Please refer to Figure 1 , Figure 1 is a flowchart of a switching method of a board area picture provided by an embodiment one of the present application, including steps S110, S120 and S130. It should be noted that steps S110, S120 and S130 are only labels for clearly explaining the correspondence between the embodiments and the drawings, and do not represent the order limitation of each step in the present embodiment. Figure 1

[0054] Step S110, periodically receiving a board area picture and a board change amount corresponding to the board area picture; wherein the board change amount is derived based on the writing amount between the latest received board area picture and the currently output board area picture;

[0055] Step S120, when receiving a board picture switching instruction, identifying all the characters in the latest received board area picture, and calculating the arithmetic mean of the character height of the latest received board area picture;

[0056] Step S130, determining whether the average character height of the latest received board area picture is greater than or equal to a preset character height threshold, and if so, switching the output picture to the latest received board area picture; ​

[0057] If no, a cropping and zooming operation is performed on the latest received board region picture;

[0058] The cropping and zooming operation includes:

[0059] S1. According to a preset rule, a plurality of sub-regions with the same aspect ratio as the original board region picture are divided in the original board region picture;

[0060] S2. The sub-region with the largest board change is taken as a candidate sub-region picture;

[0061] S3. The candidate sub-region picture is zoomed to the same size as the original board region picture to obtain a candidate region picture;

[0062] S4. It is judged whether the average character height of the candidate region picture is greater than or equal to a preset character height threshold, if yes, the output picture is switched to the candidate region picture;

[0063] S5. If no, S1, S2 and S3 are performed again on the candidate region until the average character height of the candidate region picture is greater than or equal to the preset character height threshold, and the output picture is switched to the candidate region picture with the average character height greater than or equal to the preset character height threshold.

[0064] For a camera specially used for shooting board writing, a fixedly installed industrial camera or a high-definition network camera can be used, and the installation position needs to cover the whole blackboard panorama (such as the ceiling or side wall directly in front of the classroom), to ensure that the visual angle is perpendicular to the blackboard plane to reduce perspective distortion. For the image shot by the camera, pre-processing can be performed first, such as distortion correction of the image to obtain a corrected image, and then step S110 acquires the image after pre-processing. Of course, step S110 can also directly acquire the image shot by the camera.

[0065] It should be noted that the picture acquired by step S110 can be a picture of the whole blackboard region, or a board region picture of a region divided from the blackboard region.

[0066] In step S110, the board region picture is periodically received, and at the same time, the board change corresponding to the board region picture is also received. This change is the change between the newly received board region picture and the currently used picture, i.e. the picture currently being output and not yet switched.

[0067] It should be noted that the picture currently being used and output is not necessarily the board region picture received in the previous period, because the board region picture received in the previous period may not be switched to the output picture due to various reasons.

[0068] Specifically, the board writing change amount is derived based on the writing amount between the latest received board writing area picture and the currently output board writing area picture, for example, the board writing change amount y is calculated as follows:

[0069] y = |x(T) - x(T1) |;

[0070] wherein x(T) is the board writing amount of the latest received board writing area picture, and x(T1) is the board writing amount of the currently output board writing area picture.

[0071] In step S120, when the board picture switching instruction is received, the step of switching the board writing area picture is started. The method does not limit how the board writing area picture switching instruction is generated, for example, it can be generated according to the change amount mentioned above, or it can be generated according to the teacher's action in the close-up of the teacher tracking, etc.

[0072] In the specific step of switching the board writing area picture, all the characters in the board writing area picture are first identified, and then the arithmetic mean of the character heights of these characters is calculated. The character height usually refers to the height occupied by a single character in the vertical direction, that is, the character height can be used to judge the size of the font.

[0073] In step S130, it is judged whether the character height can reach the preset character height threshold value. If it can, that is, the size of the font is appropriate, the students can clearly see the board content in the picture, and the previous board writing area picture can be directly cut off and switched to the latest received board writing area picture, and the picture switching is completed.

[0074] However, if the character height cannot reach the preset character height threshold value, the picture needs to be cropped and enlarged to ensure that the character height can reach the preset character height threshold value under the condition that the picture size is unchanged.

[0075] Specifically, in the cropping and enlarging operation, S1 first divides the original board writing area picture into a plurality of sub-regions with the same aspect ratio as the original board writing area picture according to a preset rule.

[0076] In an embodiment, the preset rule includes:

[0077] The upper left, upper right, lower left, and lower right of the original board writing area picture are respectively intercepted a sub-region with the same aspect ratio as the original board writing area picture, and the ratio of the length and width of the sub-region to the length and width of the original board writing area picture is equal to a preset proportion coefficient.

[0078] As shown in Figure 2 , the upper left, upper right, lower left, and lower right of the original board writing area picture are respectively intercepted a sub-region with the same aspect ratio as the original board writing area picture, and the ratio of the length and width of the sub-region to the length and width of the original board writing area picture is equal to a preset proportion coefficient. Figure 2It is a schematic diagram of a preset rule for an implementation manner of Embodiment 1. The algorithm will intercept a rectangle at each of the upper left, upper right, lower left, and lower right positions of the original target area. The aspect ratio of this rectangle is the same as that of the original teaching board area picture, but the length of these rectangles is only a part of the original, such as only 90% of the original. That is, the ratio of the length and width of the sub-area to the length and width of the original teaching board area picture is equal to 9 / 10. In this way, 4 sub-areas are obtained.

[0079] Then, in steps S2 and S3, among the pictures of these four sub-areas, select the sub-area with the largest change in the teaching board, and magnify this sub-area with the largest change to the same size as the original teaching board area picture. For example, as in the previous example, if the length of the rectangle is only 90% of the original, then at this time, the length and width of this sub-area are each magnified by 10 / 9 times, so as to obtain an area with the same size as the original teaching board area picture, and this area is the candidate area picture.

[0080] It should be noted here that steps S2 and S3 can be interchanged, that is, first magnify each sub-area to the same size as the original teaching board area picture, and then select the sub-area with the largest change in the teaching board as the candidate area picture.

[0081] After the magnification in step S3, step S4 makes another judgment on the candidate area picture to determine whether its character height meets the requirements. If it meets, switch to this candidate area picture, and the picture switching is completed.

[0082] If it does not meet the requirements, then execute S1, S2, and S3 on the candidate area again for a new round of iteration until the finally obtained candidate meets the requirements of the character height. After meeting the requirements, switch to this candidate area picture, and the picture switching is completed.

[0083] So far, the steps of switching the entire teaching board area picture are completed.

[0084] In one implementation manner, the preset rule includes:

[0085] Intercept a sub-area with the same aspect ratio as the original teaching board area picture at each of the upper left, middle upper, upper right, left middle, middle middle, right middle, lower left, middle lower, and lower right positions of the original teaching board area picture. The ratio of the length and width of the sub-area to the length and width of the original teaching board area picture is equal to a preset proportionality coefficient.

[0086] This implementation manner is another preset rule. The difference between this preset rule and the previous one is that the previous one is divided in a way similar to a "field" shape to obtain 4 areas, and this implementation manner is divided in a way similar to a "well" shape to obtain 9 areas.

[0087] In one implementation manner, the preset rule includes:

[0088] Select N areas with the highest writing volume from the original target area as sub-regions; where N is the preset number of sub-regions, the aspect ratio of the selected sub-regions is the same as the aspect ratio of the original writing area, and the ratio of the aspect ratio of the selected sub-regions to the aspect ratio of the original writing area is equal to the preset scaling factor.

[0089] In this embodiment, the N areas with the highest writing volume can be selected as sub-regions using a sliding window method, where N is a preset value that can be extracted and set according to the actual situation by those skilled in the art.

[0090] The highest amount of writing means the most information is recorded, which is most worth keeping for students to view. Therefore, this implementation method derives sub-regions based on the amount of writing.

[0091] In one embodiment, the method for switching the whiteboard area screen further includes step S140.

[0092] Step S140: Within a preset time after the screen switch, enter a locked state, wherein in the locked state, stop receiving new whiteboard screen switching commands.

[0093] In this embodiment, to avoid frequent screen switching, a delay lock state with a preset duration of T2 will be initiated after each switching, during which new screen switching requests will be blocked.

[0094] In this method, when the blackboard area needs to be switched, the clarity and suitability of the image are determined by the font height. Switching is only implemented when the image is clear and suitable. If the size is unsuitable, the image to be switched is cropped and enlarged according to certain rules to ensure clarity and suitability. Only after determining the optimal display area is the switch completed. This method can highlight key content while ensuring viewing quality, effectively improving the visibility and communication efficiency of multimedia blackboard writing in the teaching process.

[0095] Example 2

[0096] The second embodiment of the present invention provides a method for switching whiteboard screens, including steps S210, S220 and S230.

[0097] Step S210: Periodically receive the whiteboard display, wherein the whiteboard display is divided into several whiteboard area displays;

[0098] Step S220: Calculate the amount of change in the writing area of ​​each writing area; wherein the amount of change in the writing area is based on the amount of writing between the latest received writing area and the currently output writing area.

[0099] Step S230: Generate a whiteboard screen switching instruction for the whiteboard area with the largest whiteboard screen change, wherein the whiteboard screen switching instruction is used to instruct the whiteboard area screen switching method described in Embodiment 1 to be executed on the corresponding whiteboard area screen.

[0100] like Figure 3 As shown, Figure 3 This is a schematic diagram encompassing the entire blackboard writing area. Through image recognition, all blackboard areas within the image are located; these areas constitute the blackboard writing area. The blackboard writing area is divided into several writing areas. Figure 3 Taking the diagram as an example, the blackboard is divided into three areas: Board1, Board2, and Board3.

[0101] Dividing the blackboard display into several areas makes it easier to switch between different areas. When switching between areas, only one area needs to be switched, instead of the entire display, thus simplifying the process.

[0102] For each blackboard area, the blackboard area switching method in Example 1 can be used to switch the screen.

[0103] This method determines which area of ​​the blackboard to switch based on the amount of change in the blackboard writing. Therefore, step S220 requires calculating the amount of change in the blackboard writing for each area. The meaning of the amount of change in the blackboard writing here is the same as in Example 1.

[0104] Step S230 generates a whiteboard screen switching instruction for the whiteboard area with the largest whiteboard changes. This whiteboard screen switching instruction is the whiteboard screen switching instruction received in step S120 of Embodiment 1. When this switching instruction is received, the whiteboard area screen switching method of Embodiment 1 is executed on the corresponding whiteboard area screen.

[0105] This method divides the whiteboard area into several smaller whiteboard areas, and only switches the screen for one whiteboard area at a time, simplifying the whiteboard switching process.

[0106] Example 3

[0107] Corresponding to the method in Example 1, such as Figure 4 As shown, the present invention also provides a whiteboard area screen switching device 4, including: a receiving module 410, a calculation module 420 and an execution module 430.

[0108] The receiving module 410 is used to periodically receive the whiteboard area image and the corresponding whiteboard writing change amount; wherein, the whiteboard writing change amount is derived based on the writing amount between the latest received whiteboard area image and the currently output whiteboard area image.

[0109] The calculation module 420 is used to identify all the text in the latest received whiteboard area screen when a whiteboard screen switching instruction is received, and to calculate the arithmetic mean of the character heights in the latest received whiteboard area screen.

[0110] The execution module 430 is used to determine whether the average character height of the latest received whiteboard area screen is greater than or equal to the preset character height threshold. If so, the output screen is switched to the latest received whiteboard area screen.

[0111] If not, then perform a cropping and enlargement operation on the latest received whiteboard area image;

[0112] The cropping and enlarging operation includes:

[0113] S1. Divide the original blackboard area into several sub-areas with the same aspect ratio as the original blackboard area according to the preset rules;

[0114] S2. Select the sub-region with the largest change in the blackboard writing as the candidate sub-region image;

[0115] S3. Enlarge the candidate sub-region image to the same size as the original whiteboard area image to obtain the candidate region image;

[0116] S4. Determine whether the average character height of the candidate region screen is greater than or equal to the preset character height threshold. If so, switch the output screen to the candidate region screen.

[0117] S5. If not, execute S1, S2 and S3 again for the candidate region until the average character height of the candidate region screen is greater than or equal to the preset character height threshold, and switch the output screen to the candidate region screen where the average character height is greater than or equal to the preset character height threshold.

[0118] In one embodiment, the device for switching the blackboard area screen further includes:

[0119] The locking module is used to enter a locked state for a preset time after the screen switch, wherein in the locked state, it stops receiving new whiteboard screen switching commands.

[0120] In one implementation, the preset rule includes:

[0121] From the top left, top right, bottom left, and bottom right of the original whiteboard area, extract a sub-region with the same aspect ratio as the original whiteboard area. The ratio of the length and width of the sub-region to the length and width of the original whiteboard area is equal to a preset scaling factor.

[0122] In one implementation, the preset rule includes:

[0123] From the nine positions of the original blackboard area (top left, top center, top right, left center, center center, right center, bottom left, bottom center, and bottom right), extract a sub-region with the same aspect ratio as the original blackboard area. The ratio of the length and width of the sub-region to the length and width of the original blackboard area is equal to a preset scaling factor.

[0124] In one implementation, the preset rule includes:

[0125] Select N areas with the highest writing volume from the original target area as sub-regions; where N is the preset number of sub-regions, the aspect ratio of the selected sub-regions is the same as the aspect ratio of the original writing area, and the ratio of the aspect ratio of the selected sub-regions to the aspect ratio of the original writing area is equal to the preset scaling factor.

[0126] In this device, when the blackboard area needs to be switched, the device judges whether the image is clear and suitable based on the character height. Switching only occurs when the image is clear and suitable. If the size is unsuitable, the image to be switched is cropped and enlarged according to certain rules to ensure clarity and suitability. Only after determining the optimal display area is the switch completed. This device can highlight key content while ensuring viewing quality, effectively improving the visibility and communication efficiency of multimedia blackboard writing in the teaching process.

[0127] Corresponding to the method in Embodiment 2, the present invention also provides a device for switching blackboard images, comprising:

[0128] The acquisition module is used to periodically receive whiteboard images, wherein the whiteboard images are divided into several whiteboard area images;

[0129] The variable calculation module is used to calculate the amount of change in the writing on each writing area; wherein, the amount of change in the writing is derived based on the amount of writing between the latest received writing area and the currently output writing area.

[0130] The generation module is used to generate a whiteboard screen switching instruction for the whiteboard area with the largest whiteboard screen changes. The whiteboard screen switching instruction is used to instruct the corresponding whiteboard area screen to be operated using the aforementioned whiteboard area screen switching device.

[0131] This device divides the whiteboard area into several smaller whiteboard areas, and only switches the screen to one whiteboard area at a time, simplifying the whiteboard switching process.

[0132] Example 4

[0133] This invention also provides a storage medium storing computer instructions, which, when executed by a processor, implement the whiteboard area switching method and the whiteboard screen switching method of any of the above embodiments.

[0134] Those skilled in the art will understand that all or part of the steps of the above method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as mobile storage devices, random access memory (RAM), read-only memory (ROM), magnetic disks, or optical disks.

[0135] Alternatively, if the integrated units of this invention are implemented as software functional modules and sold or used as independent products, they can also be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the embodiments of this invention, or the parts that contribute to related technologies, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, terminal, or network device, etc.) to execute all or part of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as mobile storage devices, RAM, ROM, magnetic disks, or optical disks.

[0136] Corresponding to the computer storage medium described above, one embodiment also provides a computer device, which includes a memory, an encoder, and a computer program stored in the memory and executable on the encoder. When the encoder executes the program, it implements any of the methods for switching the whiteboard area screen and the whiteboard screen as described in the above embodiments.

[0137] The aforementioned computer equipment divides the blackboard area into several smaller areas, switching the image only on one area at a time, simplifying the switching process. When a screen switch is needed, the height of the text determines whether the image is clear and suitable. Switching only occurs when the image is clear and suitable; otherwise, the image to be switched is cropped and enlarged according to certain rules to ensure clarity and suitability. Only after determining the optimal display area is the switch completed. This computer equipment can highlight key content while maintaining viewing quality, effectively improving the visibility and communication efficiency of multimedia blackboards in the teaching process.

[0138] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0139] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for switching the display of a blackboard writing area, characterized in that, include: The system periodically receives images of the whiteboard writing area and the corresponding changes in the whiteboard writing; wherein the changes in the whiteboard writing are derived from the amount of writing between the latest received whiteboard writing area image and the currently output whiteboard writing area image. When a whiteboard screen switching command is received, all the text in the latest received whiteboard area screen is identified, and the arithmetic mean of the character heights in the latest received whiteboard area screen is calculated. Determine whether the average character height of the latest received whiteboard area image is greater than or equal to the preset character height threshold. If so, switch the output screen to the latest received whiteboard area image. If not, then perform a cropping and enlargement operation on the latest received whiteboard area image; The cropping and enlarging operation includes: S1. Divide the original blackboard area into several sub-areas with the same aspect ratio as the original blackboard area according to the preset rules; S2. Select the sub-region with the largest change in the blackboard writing as the candidate sub-region image; S3. Enlarge the candidate sub-region image to the same size as the original whiteboard area image to obtain the candidate region image; S4. Determine whether the average character height of the candidate region screen is greater than or equal to the preset character height threshold. If so, switch the output screen to the candidate region screen. S5. If not, execute S1, S2 and S3 again for the candidate region until the average character height of the candidate region screen is greater than or equal to the preset character height threshold, and switch the output screen to the candidate region screen where the average character height is greater than or equal to the preset character height threshold.

2. The method for switching the blackboard area screen according to claim 1, characterized in that, Also includes: Within a preset time after the screen switch, it enters a locked state, during which it stops receiving new whiteboard screen switching commands.

3. The method for switching the blackboard area screen according to claim 1 or 2, characterized in that, The preset rules include: From the top left, top right, bottom left, and bottom right of the original whiteboard area, extract a sub-region with the same aspect ratio as the original whiteboard area. The ratio of the length and width of the sub-region to the length and width of the original whiteboard area is equal to a preset scaling factor.

4. The method for switching the blackboard area screen according to claim 1 or 2, characterized in that, The preset rules include: From the nine positions of the original blackboard area (top left, top center, top right, left center, center center, right center, bottom left, bottom center, and bottom right), extract a sub-region with the same aspect ratio as the original blackboard area. The ratio of the length and width of the sub-region to the length and width of the original blackboard area is equal to a preset scaling factor.

5. The method for switching the blackboard area screen according to claim 1 or 2, characterized in that, The preset rules include: Select N areas with the highest writing volume from the original target area as sub-regions; where N is the preset number of sub-regions, the aspect ratio of the selected sub-regions is the same as the aspect ratio of the original writing area, and the ratio of the aspect ratio of the selected sub-regions to the aspect ratio of the original writing area is equal to the preset scaling factor.

6. A method for switching blackboard displays, characterized in that, include: The whiteboard images are received periodically, wherein the whiteboard images are divided into several whiteboard area images; Calculate the amount of writing change in each writing area; wherein the amount of writing change is based on the amount of writing between the latest received writing area and the currently output writing area. A whiteboard screen switching instruction is generated for the whiteboard area with the largest whiteboard changes, wherein the whiteboard screen switching instruction is used to instruct the whiteboard area screen to perform the whiteboard area screen switching method as described in any one of claims 1-5.

7. A device for switching the display of a blackboard writing area, characterized in that, include: The receiving module is used to periodically receive the whiteboard area image and the corresponding whiteboard writing change amount; wherein, the whiteboard writing change amount is derived based on the writing amount between the latest received whiteboard area image and the currently output whiteboard area image; The calculation module is used to identify all the text in the latest received whiteboard area screen when a whiteboard screen switching command is received, and to calculate the arithmetic mean of the character heights in the latest received whiteboard area screen. The execution module is used to determine whether the average character height of the latest received whiteboard area image is greater than or equal to the preset character height threshold. If so, the output screen is switched to the latest received whiteboard area image. If not, then perform a cropping and enlargement operation on the latest received whiteboard area image; The cropping and enlarging operation includes: S1. Divide the original blackboard area into several sub-areas with the same aspect ratio as the original blackboard area according to the preset rules; S2. Select the sub-region with the largest change in the blackboard writing as the candidate sub-region image; S3. Enlarge the candidate sub-region image to the same size as the original whiteboard area image to obtain the candidate region image; S4. Determine whether the average character height of the candidate region screen is greater than or equal to the preset character height threshold. If so, switch the output screen to the candidate region screen. S5. If not, execute S1, S2 and S3 again for the candidate region until the average character height of the candidate region screen is greater than or equal to the preset character height threshold, and switch the output screen to the candidate region screen where the average character height is greater than or equal to the preset character height threshold.

8. A device for switching blackboard images, characterized in that, include: The acquisition module is used to periodically receive whiteboard images, wherein the whiteboard images are divided into several whiteboard area images; The variable calculation module is used to calculate the amount of change in the writing on each writing area; wherein, the amount of change in the writing is derived based on the amount of writing between the latest received writing area and the currently output writing area. The generation module is used to generate a whiteboard screen switching instruction for the whiteboard area with the largest whiteboard screen changes. The whiteboard screen switching instruction is used to instruct the corresponding whiteboard area screen to be operated using the whiteboard area screen switching device as described in claim 6.

9. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the method as described in any one of claims 1-6.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the method as described in any one of claims 1-6.

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