JP2012133210A - Display device, screen image transfer method and program - Google Patents

Abstract

In a technology for sharing a screen by displaying a display screen displayed on a display device on another device, the display screen displayed on the display device based on an operation can be quickly displayed without increasing the device load. To display on other devices.
In a display device, when a user performs an operation on a capture unit that captures a screen image displayed on a display unit and obtains a captured image, and an operation unit is operated by a user, the operation is performed from the time when the operation is performed. The screen image display time, which is the time until the screen image by the operation is displayed on the display unit, is estimated, and when the screen image display time elapses from the time when the operation is performed, Screen image display time estimation instruction means for instructing capture of a screen image, and transfer means for transferring the captured image captured by the capture means based on the instruction to the other device via a communication unit, Prepare.
[Selection] Figure 2

Description

  The present invention relates to a technique for screen sharing by causing a display screen displayed on a display device to be displayed on another display device.

  Conventionally, there is a technique for sharing a display screen among a plurality of devices. For example, in Patent Document 1, a display device to be monitored collects information on a screen to be displayed in response to a user operation, transmits the screen information to another display device, and the other display device displays the screen information. A technique for reproducing and monitoring a display screen based on this is described.

  Japanese Patent Application Laid-Open No. 2004-228688 describes a technique for sharing screen display contents among a plurality of terminal devices and sharing operations such as writing from the terminal to the screen. Patent Document 3 discloses a technology related to a collaborative work support system that displays a common screen among a plurality of users on a screen of a display device of each of a plurality of users, and supports collaborative work performed through the screen display. Is described. Other prior art documents related to the present application include Patent Documents 4 and 5.

JP 2010-55153 A JP 2006-323607 A JP-A-11-65975 JP 2010-186369 A JP 2010-147905 A

  As described above, by using a technique for sharing a display screen among a plurality of display devices, for example, a display device (first display device) used by a user unfamiliar with the operation of the display device (assisted side). By displaying the display screen to be displayed on the display device (second display device) of the user (assist side) who assists the operation, the assist side user can see the display screen to the user on the assisted side. On the other hand, it is possible to remotely and carefully teach the operation method of the first display device.

  In the technology of assisting operations by sharing the display screen, changes such as the update of the display screen displayed on the assisted side are reflected in real time on the display device on the assist side in order to perform appropriate assistance. It is desirable.

  However, for that purpose, it is necessary to capture the display screen on the assisted side and transfer the captured image to the display device on the assist side at a very short time interval, which is not preferable from the viewpoint of device load and network load. . Further, in this case, since there is a period during which the display screen on the assisted side does not change, the captured image is also sent unnecessarily.

  On the other hand, if the time interval for capturing the display screen on the assisted side is widened to reduce the device load and the network load, an appropriate display screen corresponding to the operation on the assisted side can be quickly displayed on the assist side display device. Cannot be displayed on the screen, and there is a possibility that accurate assist cannot be performed.

  For example, even if the assisting person confirms the screen displayed when an operation (such as pressing a button) by the person being assisted is performed and wants to perform subsequent assistance, Such an assist cannot be performed unless the screen displayed on the side is successfully displayed on the display device of the assistant.

  The present invention has been made in view of the above points, and in the technology for screen sharing by displaying the display screen displayed on the first display device on the second display device, the device load and the network load are reduced. An object of the present invention is to provide a technique for quickly displaying a display screen displayed on a first display device based on an operation on a second display device without increasing the display screen.

  In order to solve the above-described problems, the present invention is a display device that includes a display unit, an operation unit, and a communication unit, and displays a screen image displayed on the display unit on another device to share the screen. When a user performs an operation on a capture unit that captures a screen image displayed on the display unit and obtains a captured image, and the operation unit is operated, the operation is performed from the time when the operation is performed. The screen image display time which is the time until the screen image is displayed on the display unit is estimated, and when the screen image display time elapses from the time when the operation is performed, the screen is displayed on the capture unit. A screen image display time estimation instruction unit for instructing image capture, and the captured image captured by the capture unit based on the instruction via the communication unit. And transfer means for transferring to the other device Te configured as a display device, characterized in that it comprises a.

  The display device includes capture control information storage means for storing operation information indicating operation contents and a predetermined time in association with each other, and the screen image display time estimation instruction means corresponds to the operation contents by the user. A predetermined time may be acquired from the capture control information storage unit, and the screen image display time may be estimated based on the predetermined time.

  The screen image display time estimation instruction unit may estimate the screen image display time based on the predetermined time acquired from the capture control information storage unit and processing load information of the display device.

  Further, when the operation by the user is an instruction to download content from a server on the network, the screen image display time estimation instructing unit is configured to estimate that a screen indicating download start is displayed on the display unit. Instructing the capture means to capture a screen image at a time point 1, and further capturing the screen image at a second time point when it is estimated that the download is completed and the screen after the download is completed is displayed. The capture unit may be instructed.

  Further, the display device includes a traffic measurement unit that measures a communication amount per unit time of data transmitted and received in the communication unit, and the screen image display time estimation instruction unit is a communication measured by the traffic measurement unit. The point in time when the amount of traffic reaches or exceeds a predetermined value is determined as the first point in time, and then the point in time when the traffic measured by the traffic measuring means becomes equal to or less than a predetermined value is defined as the second point in time. You may comprise so that it may determine.

  Further, the transfer means compares the latest captured image as a transfer candidate with the captured image transferred immediately before, and if there is a difference between these captured images, transfers the latest captured image, When there is no difference between the captured images, the latest capture image is not transferred, and after a predetermined time has elapsed, the capture unit acquires the captured image again as the latest captured image that is a transfer candidate. May be.

  The present invention can also be configured as a screen image transfer method corresponding to processing executed by the display device, and a computer including a display unit, an operation unit, and a communication unit functions as each unit in the display device. It can also be configured as a program for causing

  According to the present invention, in the technology for sharing a screen by displaying the display screen displayed on the first display device on the second display device, the first screen is operated based on the operation without increasing the device load and the network load. It is possible to provide a technique for quickly displaying the display screen displayed on one display device on the second display device.

It is a system configuration figure concerning an embodiment of the invention. 3 is a functional configuration diagram of the display device 1. FIG. It is a figure which shows an example of the table stored in the capture control information storage part. It is a figure for demonstrating the operation | movement outline | summary of a system. FIG. 11 is a sequence diagram for explaining a constant time interval capture process in the display device 1. 11 is a sequence diagram for explaining a capture process according to an operation in display device 1. FIG. It is a sequence diagram for demonstrating a modification.

  Embodiments of the present invention will be described below with reference to the drawings.

(System configuration)
FIG. 1 shows a system configuration according to an embodiment of the present invention. As shown in FIG. 1, the system according to the present embodiment has a configuration in which a display device 1 and a display device 2 are connected via a communication network 3.

  In the present embodiment, each of display devices 1 and 2 may be a PC or a mobile terminal such as a mobile phone. The communication network 3 is a network that can transmit and receive image data and the like.

  In the present embodiment, it is assumed that the screen displayed on the display device 1 is displayed on the display device 2. That is, the captured image of the screen displayed on the display device 1 is transmitted to the display device 2, and the display device 2 performs screen display based on the captured image. The display device 2 only needs to have a function of displaying screen information received from the display device 1.

  FIG. 2 shows a functional configuration diagram of the display device 1 according to the present embodiment. As shown in FIG. 2, the display device 1 includes a communication unit 11, a display unit 12, an operation unit 13, a display information generation unit 14, a display processing unit 16, a capture unit 17, a captured image storage unit 18, and transfer screen information generation. A transfer unit 19, a capture control unit 20, and a capture control information storage unit 21 are provided.

  The communication unit 11 is a functional unit for communicating data and the like with other devices via the communication network 3. The display unit 12 is a so-called display and is a functional unit that displays an image. The operation unit 13 is a button, a keyboard, or the like for the user to input information and give various instructions to the display device 1. The operation unit 13 may be a touch screen configured integrally with the display unit 12.

  The display information generation unit 14 is a functional unit that generates display information to be displayed on the display unit 12 and includes functions corresponding to various applications and processing programs. Examples of applications included in the display information generation unit 14 include a Web browser, a camera application, and a mail application.

  Further, for example, when the display device 1 is a mobile phone, the display information generation unit 14 displays an operation screen on the display unit 12, receives a telephone number input, performs a calling process, etc. It is provided in a general mobile phone such as a phone book application that performs display and management, and includes various functions that perform screen display.

  The display information is, for example, text information, image information, information in which text and an image are mixed, and further includes display position information in the screen displayed on the display unit 12. The display information includes identification information indicating the type (for example, the extension of the file name is a kind of identification information).

  The display processing unit 16 is a functional unit that receives display information from the display information generation unit 14 and displays the display information on the display unit 12. The display processing unit 16 temporarily stores display information (for example, text + image) or a graphic area. Storage area (graphic memory, etc.), and graphic processing for display is performed.

  The capture unit 17 obtains (captures) a screen image displayed on the display unit 12 by the display processing unit 16 based on an instruction from the capture control unit 20 and stores the screen image in the captured image storage unit 18. Part.

The transfer screen information generation / transfer unit 19 is a functional unit that transfers the captured image acquired by the capture unit 17 to the display device 2 as transfer screen information. Note that a compressed image may be generated by performing compression processing on the captured image and transferred as transfer screen information.
The capture control unit 20 is a functional unit that issues a capture instruction to the capture unit 17, and includes a fixed time interval capture instruction unit 201, a screen update time estimation capture instruction unit 202, and a traffic monitoring unit 203.

  The fixed time interval capture instruction unit 201 has a function of instructing the capture unit 17 to perform capture at a predetermined fixed time interval.

  The screen update time estimation capture instruction unit 202 receives the operation information corresponding to the operation from the display information generation unit 14 that performs processing corresponding to the operation based on the operation from the operation unit 13, and the operation information is received from the time when the operation information is received. When the screen update time, which is the time until the screen image corresponding to the information is displayed, is determined (estimated), and the estimated screen update time has elapsed since the time when the operation information was received (≈ time when the operation was performed) Thus, a function for instructing the capture unit 17 to perform capture is provided.

  FIG. 3 shows an example of a table stored in the capture control information storage unit 21 in the present embodiment. As shown in FIG. 3, in the capture control information storage unit 21, screen update times corresponding to each operation information are recorded. These pieces of information are information registered in advance by setting. “Operation information” is, for example, “application A start operation”, “application end operation”, “Web download operation”, and the like. For example, the screen update time when the operation information is “startup operation of application A” is the time from when the operation is performed until the first screen of application A is displayed.

  The screen update time estimation capture instruction unit 202 acquires the screen update time corresponding to the operation information by searching the capture control information storage unit 21 using the operation information received from the display information generation unit 14 and acquires the screen update time. When the elapse of the update time is detected, a capture instruction is given to the capture unit 17.

  In addition to using only the preset screen update time as described above, the screen update time may be estimated in consideration of the processing load of the display device 1. In this case, for example, the screen update time estimation capture instruction unit 202 acquires the screen update time from the capture control information storage unit 21 and the CPU usage rate from the OS of the computer constituting the display device 1. The screen update time may be increased or decreased according to the CPU usage rate, and this may be used as the screen update time. For example, when the CPU usage rate is equal to or higher than a predetermined X percent, a time obtained by multiplying the screen update time acquired from the capture control information storage unit 21 by a coefficient α (α is 1 or more) is used as the screen update time. When the CPU usage rate is equal to or less than a predetermined Y percent, the time obtained by multiplying the screen update time acquired from the capture control information storage unit 21 by the coefficient α (α is 1 or less) is used as the screen update time. Can be configured.

  Note that the operation information set in advance in the capture control information storage unit 21 may be only related to an operation that requires a certain amount of time for screen display (screen update). In this case, for example, when the screen update time estimation capture instruction unit 202 detects that the operation information received from the display information generation unit 14 is not in the capture control information storage unit 21, it immediately responds to the capture unit 17. Instruct capture. Alternatively, capture is instructed after elapse of a predetermined time (a time shorter than any time set in the capture control information storage unit 21).

  In addition, the screen update time estimation capture instruction unit 202 has received, from the display information generation unit 14, operation information indicating that content (Web page, image file, music, etc.) is downloaded from a server on the network as operation information. In this case, the capture unit 17 is instructed to perform the first capture at the time when it is estimated that a screen indicating the start of download (eg, a screen indicating that download is in progress) is displayed. A function is also provided for instructing the capture unit 17 to perform the second capture at the time when it is estimated that this screen is displayed.

  In this function, for example, the screen update time estimation capture instruction unit 202 is estimated that the screen indicating the download start is displayed at the time when the control information indicating that the download has started is acquired from the display information generation unit 14. The time when the control information indicating that the download is completed is acquired from the display information generation unit 14 as the time when it is estimated that the screen after the download is completed.

  Instead of using the control information acquired from the display information generating unit 14 as described above, the following processing may be performed. The following processing is particularly effective when the above control information is not acquired or cannot be acquired.

  In this case, when the screen update time estimation capture instruction unit 202 receives operation information corresponding to downloading content from a server on the network from the display information generation unit 14, it instructs the traffic monitoring unit 203 to monitor traffic. Receiving the instruction, the traffic monitoring unit 203 measures the communication amount of data per unit time in the communication unit 11 and notifies the screen update time estimation capture instruction unit 202 of the communication amount. The screen update time estimation capture instruction unit 202 instructs the capture unit 17 to perform the first capture when the communication amount becomes a predetermined value or more, and then the communication amount becomes equal to or less than the predetermined value. The capture unit 17 is instructed to perform the second capture.

The capture unit 17, the captured image storage unit 18, the transfer screen information generation / transfer unit 19, the capture control unit 20, and the capture control information storage unit 21 in the display device 1 are computers including a CPU, a memory, a communication interface, and the like (described above). This can be realized by causing a program that describes the processing corresponding to the functional unit to be executed on a display information generating unit 14 or a display processing unit 16 that is a functional unit other than the above. The program can be recorded and distributed on a recording medium such as a portable memory. It is also possible to download the program from a server on the network and install it. The “computer” may be a mobile phone or the like having the function of “computer”.
(System operation)
Next, the operation of the system in this embodiment will be described. First, the outline of the operation of the system will be described with reference to the sequence chart of FIG.

  The display device 2 transmits a screen sharing request to the display device 1 (step 1), and the display device 1 transmits screen sharing permission to the display device 2, whereby screen sharing is started. Thereafter, the screen image displayed on the display device 1 is captured (step 3), the transfer screen information is transferred to the display device 2 (step 4), and the screen image is displayed on the display device 2 (step 5). Thus, screen sharing is realized.

  FIG. 4 shows an example in which a screen sharing request is transmitted from the display device 2 and the display device 1 sends a screen sharing permission to the display device 2. However, the screen sharing request is transmitted from the display device 1, and the display device 2 The sharing permission may be sent to the display device 2. Moreover, starting the screen sharing process by transmitting and receiving a screen sharing request and a screen sharing permission is merely an example, and screen sharing may be started by another procedure.

(Details of operation)
Hereinafter, the processing executed by the display device 1 (particularly, the capture control unit 20 and the capture unit 17) after entering the screen sharing state will be described in detail with reference to flowcharts.

  First, with reference to FIG. 5, a capture process at a constant time interval under the control of the constant time interval capture instruction unit 201 will be described. The processing described with reference to FIG. 5 is basically processing that is always performed when screen sharing is performed regardless of user operations.

  The constant time interval capture instruction unit 201 of the capture control unit 20 counts up a timer to check whether a predetermined time has elapsed since the previous capture instruction by the constant time interval capture instruction unit 201 (step 11). When a certain time has elapsed, the certain time interval capture instruction unit 201 instructs the capture unit 17 to perform screen capture (step 12). Upon receiving the instruction, the capture unit 17 captures the screen image displayed on the display unit 12 from the display processing unit 16 and stores it as a captured image in the captured image storage unit 18 (step 13).

  Next, the transfer screen information generation and transfer unit 19 transfers the captured image acquired in step 13 to the display device 2 as transfer screen information (step 14). When the transfer is completed, a timer in the capture instruction unit at regular time intervals is initialized (step 15), and the processing from step 11 is repeated. The display device 2 performs screen display based on the received transfer screen information.

  On the other hand, it is assumed that the operation is performed from the operation unit 13 by the user while the processing is performed at a certain time interval as described above. Processing in this case (mainly processing by the screen update time estimation capture instruction unit 202) will be described with reference to a flowchart in FIG.

  Due to the operation, the surface update time estimation capture instruction unit 202 of the capture control unit 20 receives operation information corresponding to the operation from the display information generation unit 14 (step 21).

  The screen update time estimation capture instruction unit 202 that has received the operation information determines whether or not the operation information is operation information related to content download (step 22). If the operation information is not operation information related to content download, the process proceeds to step 23. If the operation information is related to content download, the process proceeds to step 24.

  If the operation information is not related to content download (No in Step 22), the screen update time estimation capture instruction unit 202 refers to the capture control information storage unit 21 to obtain the screen update time corresponding to the received operation information. (Estimate) (Step 23), and when the screen update time has elapsed from the time when the operation information is received, the capture unit 17 is instructed to perform capture (Steps 25 and 26). After that, the screen capture is performed (step 27) and the captured image is transferred (step 28), as in the above-described processing at regular time intervals.

  As described above, the CPU usage rate may be acquired, the screen update time may be adjusted according to the CPU usage rate, and this may be used as the screen update time. When operation information not set in the capture control information storage unit 21 is received, a predetermined time may be used as the screen update time. It should be noted that after step 28, it may be instructed to initialize the constant time measurement to the constant time interval capture instruction unit 201.

  When the received operation information is operation information related to content download (Yes in Step 22), the screen update time estimation capture instruction unit 202 displays a screen indicating download start (eg, screen indicating that download is in progress). The capture unit 17 is instructed to perform the first capture when it is estimated that is displayed (step 24), whereby the first capture and transfer are performed (steps 31 and 32). Then, the capture unit 17 is instructed to perform the second capture at the time when the download is completed and the screen after the download is completed is displayed (step 33), thereby performing the second capture and transfer. (Steps 34 and 35).

  As described above, the screen update time estimation capture instruction unit 202 displays a screen indicating download start at the time when the control information indicating that the download corresponding to the operation information is started is acquired from the display information generation unit 14. The time when the control information indicating that the download corresponding to the operation information is completed is acquired from the display information generation unit 14 as the time when it is estimated that the screen after the download is completed. Can do. In this case, however, the display information generation unit 14 has a function of notifying the screen update time estimation capture instruction unit 202 of the control information.

  Alternatively, the screen update time estimation capture instruction unit 202 instructs the traffic monitoring unit 203 to monitor traffic, acquires the communication amount per unit time of data in the communication unit 11 from the traffic monitoring unit 203, and the communication amount is determined in advance. The capture unit 17 is instructed to perform the first capture when the value exceeds the predetermined value, and then the capture unit 17 is instructed to perform the second capture when the traffic becomes equal to or less than a predetermined value. May be performed.

  Note that when the operation information is operation information related to content download, it is less necessary to transfer the display screen during the period from the first capture to the second capture to the display device 2. The screen update time estimation capture instruction unit 202 instructs the capture instruction unit 201 to stop measuring the fixed time at the time when the second capture is performed. The capture instruction unit 201 may be instructed to resume (or initialize) measurement for a certain period of time. As a result, in the period from the first capture to the second capture by the download operation, capture is not performed at regular time intervals.

<Modification>
In the processing described with reference to FIG. 6, the actual screen update time may change due to various factors, and thus the captured image acquired by performing the capture instruction has not yet been updated for the operation. It may be an image. Therefore, as shown below, the current captured image (hereinafter referred to as a transfer candidate capture image) is compared with the capture image transferred immediately before (hereinafter referred to as the previous transfer capture image). The transfer candidate capture image may be transferred.

  In this case, the processing content from where the capture instruction is performed will be described with reference to the flowchart of FIG. The following processing is assumed to be applied to any or all of the processing in steps 26 to 28, the processing in steps 24 to 32, and the processing in steps 33 to 35 in FIG. Further, in the following processing, when the capture image is transferred (including the case of FIG. 5), the transfer screen information generation / transfer unit 19 uses the transferred capture image as the previous transfer capture image. Hold on.

  When the screen update time estimation capture instruction unit 202 instructs the capture unit 17 to perform capture (step 101), the capture unit 17 captures the screen and uses the captured image as a transfer candidate capture image. 18 (step 102).

  The transfer screen information generation / transfer unit 19 acquires the previous transfer capture image and the transfer candidate capture image from the capture image storage unit 18, compares them, and determines whether there is a difference between them (see FIG. Step 103). As for comparison between captured images, it is possible to compare all the pixels for each pixel, or to compare some pixels (for example, skipped areas) in order to reduce the processing amount. Good.

  When the determination result in step 103 is “no difference”, the screen update time estimation capture instruction unit 202 is notified of the determination result, and the screen update time estimation capture instruction unit 202 passes the predetermined time (step 104). Returning to step 101, the processing from the capture instruction is repeated. The “predetermined time” here is a relatively short time, and may be, for example, a predetermined fixed value (for example, 10 ms), or obtain the screen update time from the capture control information storage unit 21 (FIG. 3). If it is, the value may be a fraction (for example, half) of the screen update time.

  When the determination result in step 103 is “difference exists”, the transfer screen information generation / transfer unit 19 transfers the transfer candidate capture image, and uses the transferred capture image as a new previous transfer capture image. 18 (step 105).

  As a result of the comparison, if there is no change in the captured image as a result of comparison, the capture is performed again after a predetermined time (short time) has elapsed, and the capture is repeated until a change appears in the captured image. As a result, it is possible to transfer only when the target captured image has changed from the captured image at the previous transfer, so it is possible to perform more efficient transfer without waste.

(Effects of the embodiment)
As described above, according to the present embodiment, after an operation (such as a key press), the time required to update the screen of the application or the like is estimated, and the capture process is performed after the elapsed time. It is possible to capture an appropriate screen, transfer it quickly, and avoid capturing a screen that has not been updated.

  When downloading a Web page, ringtone, or the like, the first capture is performed at the start of the download and the second capture is performed after the download is completed. Not only can the download be started and it can be ascertained that the download has been completed, but the influence on the download process in the display device 1 can be minimized.

  Also, communication traffic is monitored using the traffic monitoring unit 203, and the first capture is performed when the traffic volume per unit time exceeds a certain value, and the second capture is performed when the traffic amount is less than a certain value. Therefore, even when the download start / end trigger cannot be acquired (not), capture corresponding to the start / end of the download can be accurately performed. Also, with this method, it is not necessary to modify each application (display information generation unit), and mounting is easy.

  The present invention is not limited to the above-described embodiments, and various modifications and applications are possible within the scope of the claims.

DESCRIPTION OF SYMBOLS 1, 2 Display apparatus 3 Communication network 11 Communication part 12 Display part 13 Operation part 14 Display information generation part 16 Display processing part 17 Capture part 18 Capture image storage part 19 Screen information generation transfer part 20 Capture control part 21 Capture control information Storage unit 201 Capture interval at regular intervals 202 Screen update time estimation capture unit 203 Traffic monitoring unit

Claims (8)

A display device that includes a display unit, an operation unit, and a communication unit, and performs screen sharing by displaying a screen image displayed on the display unit on another device,
Capture means for capturing a screen image displayed on the display unit and obtaining a captured image;
When an operation is performed by the user on the operation unit, a screen image display time that is a time from when the operation is performed until the screen image by the operation is displayed on the display unit is estimated, Screen image display time estimation instruction means for instructing the capture means to capture a screen image when the screen image display time has elapsed from the time when the operation was performed;
Transfer means for transferring the captured image captured by the capture means based on the instruction to the other device via the communication unit;
A display device comprising: The display device includes capture control information storage means for storing operation information indicating operation contents and a predetermined time in association with each other,
The screen image display time estimation instruction unit acquires a predetermined time corresponding to the content of the operation by the user from the capture control information storage unit, and estimates the screen image display time based on the predetermined time. The display device according to claim 1.   3. The screen image display time estimation instruction unit estimates the screen image display time based on the predetermined time acquired from the capture control information storage unit and processing load information of the display device. The display device described in 1. In the case where the operation by the user is an instruction to download content from a server on the network, the screen image display time estimation instruction means is a first unit that estimates that a screen indicating download start is displayed on the display unit. Instructing the capture means to capture a screen image at a time point, and further capturing the screen image at a second time point when it is estimated that the download is completed and the screen after the download is completed is displayed. The display device according to any one of claims 1 to 3, characterized by: The display device includes traffic measurement means for measuring a communication amount per unit time of data transmitted and received in the communication unit,
The screen image display time estimation instruction means determines the time point when the traffic measured by the traffic measurement means is equal to or greater than a predetermined value as the first time point, and is then measured by the traffic measurement means. The display device according to claim 4, wherein a time point at which the traffic becomes equal to or less than a predetermined value is determined as the second time point. The transfer means compares the latest captured image as a transfer candidate with the captured image transferred immediately before and transfers the latest captured image if there is a difference between the captured images. When there is no difference between images, the capture unit does not transfer the latest capture image, and after a predetermined time has elapsed, the capture unit acquires the capture image again as the latest capture image that is a transfer candidate. The display device according to claim 1. A screen image transfer method executed by a display device that includes a display unit, an operation unit, and a communication unit and performs screen sharing by displaying a screen image displayed on the display unit on another device,
When an operation is performed by the user on the operation unit, a screen image display time that is a time from when the operation is performed until the screen image by the operation is displayed on the display unit is estimated, A screen image display time estimation instruction step for instructing capture means included in the display device to capture a screen image at the time when the screen image display time has elapsed since the operation was performed;
A transfer step of transferring the captured image captured by the capture unit based on the instruction to the other device via the communication unit;
A screen image transfer method comprising:   The program for functioning a computer provided with a display part, an operation part, and a communication part as each means in the display apparatus of any one of Claims 1 thru | or 6.

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