JP2006243324A - Image transmission system and image transmission method - Google Patents

Abstract

In a conventional wireless image transmission system, when priority is given to image quality, the response speed is always slowed down, which makes the user uncomfortable.
An image is divided and compressed, and when the processing speed is slow or a still image, a display flag is added to all the divided compressed data to set a speed priority mode. When the processing speed is high or a moving image, a display flag is added only to the divided compressed data to be transmitted last, and the image quality priority mode is set. The image projection apparatus updates the display only when decompressing the compressed data to which the display flag is added. Eliminate user discomfort by automatically switching between speed priority mode and image quality priority mode.
[Selection] Figure 12

Description

  The present invention relates to a transmission system and an image transmission method for an image transmitted from an image generation apparatus such as a personal computer (hereinafter referred to as “PC”) to an image projection apparatus such as a projector.

  In recent years, projectors that receive an image signal from a PC and project the screen of the PC onto a screen or the like are becoming popular. This projector is often used in conferences and workshops because the presentation material edited on a PC can be projected on a screen to visually express the contents to be conveyed. A system using a plasma display panel (PDP) instead of a projector as an image projection apparatus has also been proposed.

  Usually, the PC and the projector exchange image signals by analog connection via RGB cables or digital connection via Digital Video Interface (DVI). However, it takes time and labor to connect the PC and the projector, and in particular when the data to be projected is stored separately in a plurality of PCs, the connection between the PC and the projector must be reconnected each time. Therefore, for the purpose of improving the usability of the projector, a wireless video transmission apparatus that transmits an image signal from a PC to the projector via a wireless (wireless) LAN or the like has been proposed.

  However, since the bandwidth of a wireless LAN is generally narrower than that of wired communication, the transmission number (frame rate) per unit time is limited when digital data of an image signal is transmitted as it is. Normally, with an RGB cable or a DVI connection, about 60 images can be displayed per second. For example, if the image data is 24 bps with XGA, there is a data amount of 18 MBit per sheet, and has a bandwidth of 18 Mbps, for example. Even if the communication channel is used to the maximum, only one piece of data can be transmitted per second. Therefore, a method of compressing and transmitting digital data is used, and a technique for improving the compression rate and compression speed and increasing the frame rate has been devised (see, for example, Patent Document 1).

In addition, it is known that the movement is smoothed by suppressing the fluctuation in a limited frame rate. (For example, see Patent Document 2)
The image transmission system is shown in FIG. In this system, an example in which a PC is used as an image generation apparatus and a PDP is used as an image projection apparatus is described. FIG. 14 is a block diagram showing a hardware configuration of a transmission PC 501 and a reception PDP 502 that constitute a conventional image transmission system.

  In FIG. 14, 511 is a keyboard, 512 is a display such as a liquid crystal panel, 513 is a PC card I / F for mounting a wireless modem, 514 is an image memory, 515 is a control unit including a CPU, and 520 is a transmission side. It is a wireless modem. The PDP 502 includes a receiving-side wireless modem 531, a display (PDP) 532, an image memory 533 for storing data sent from a PC, and a control unit 534 including a CPU.

  A presentation image to be transmitted to the PDP 502 is stored in the image memory 514 of the PC 1. When the presentation image stored in the image memory 514 is transmitted from the PC 501 to the PDP 502 and displayed on the PDP 502, the operator designates the presentation image to be transmitted and inputs a transmission command to the PC 501.

When a transmission command is input, a transmission image for one page on the PC 501 is selected. In the PDP 502, it is determined whether or not the image memory 533 is free. If there is a free space, the permission command is transmitted to the PC 501. When the permission command is transmitted, the load state of the CPU in the control unit 534 is transmitted to the PC 501. The PC 501 receives the load state, and does not transmit in the case of a high load state according to the load state. In the middle load state, transmission is performed intermittently. In a low load state, images are transmitted continuously. When the load state on the PDP 502 side is a medium load, intermittent display without special effects such as fade-in and fade-out is performed. When the load state is low, normal display with fade-in and fade-out enabled is performed. The display 512 of the PC 501 does not display when the load state of the PC 501 is high, but displays when the load state is low.
JP 2004-193818 A (FIG. 1 on pages 7-8 and 15) JP 2001-22681 A (pages 4-6, FIG. 1)

  However, in the above-described conventional configuration, intermittent display and normal display are switched according to the load state of the CPU, and smooth display is performed regardless of the load state. When the processing of the PC or projector is slow, there is a problem that the response speed until display is slow, and the speed is reduced regardless of whether it is a moving image or a still image, and the user feels uncomfortable.

  SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and an image transmission system that does not cause discomfort to the user by automatically switching between a speed priority mode with priority on response speed and an image quality priority mode with priority on screen accuracy. And to provide a method.

  The invention according to claim 1 of the present invention is an image transmission system including an image generation device for generating an image and an image projection device for projecting an image transmitted from the image generation device. The generation apparatus includes an image capture unit that captures an image, a division compression unit that divides and compresses the captured image for each region, and a display flag that indicates whether to immediately display the data that is divided and compressed for each region A display flag selection / addition means for determining whether to add or not, and a transmission means for transmitting each divided and compressed data. The image projection apparatus receives the divided and compressed data for each data, and decompresses the compression. And an updating unit that determines whether a display flag exists for each data and updates the display after decompressing the data for which the display flag exists. An image transmission system according to symptoms, by switching the accuracy of the response speed priority speed priority mode and the screen of the image quality priority mode priority automatically, can realize an image transmission system which does not give an unpleasant feeling to the user.

  According to a second aspect of the present invention, the display flag selection / addition means selects whether to add a display flag based on a processing speed of the image generation device or the image projection device. Yes, if the PC or projector process is slow, automatically select the speed priority mode to make the response appear fast, and if the PC and projector process is fast, determine that the response speed is sufficient, An image transmission system that can automatically shift to the image quality priority mode and does not cause discomfort to the user can be realized.

  According to a third aspect of the present invention, the display flag selection / addition means selects whether or not to add a display flag depending on whether or not the image displayed by the image generation device is continuously changing. Depending on whether the screen on the PC is a moving image or a still image, it can automatically switch between the speed priority mode with priority on response speed and the image quality priority mode with priority on screen accuracy. And an image transmission system that does not cause discomfort to the user.

  According to a seventh aspect of the present invention, there is provided an image transmission method for transmitting an image from an image generation device that generates an image to an image projection device that projects the image, and the image generation device captures an image. Image capture step to be performed, divided compression step to divide and compress the captured image for each region, and display flag indicating whether to display immediately or not to the data compressed and divided for each region A display flag selection adding step for determining the data and a transmission step for transmitting each of the divided and compressed data.In the image projection apparatus, the step of receiving the divided and compressed data for each data, and the decompressing step of decompressing the compression, An update step that determines whether a display flag exists for each data and updates the display after decompressing the data for which the display flag exists. An image transmission method that does not cause discomfort to the user by automatically switching between a speed priority mode with priority on response speed and an image quality priority mode with priority on screen accuracy. Can be realized.

  According to an eighth aspect of the present invention, the display flag selection / addition step selects whether to add a display flag based on a processing speed of the image generation device or the image projection device. When the PC or projector process is slow, the speed priority mode is automatically selected to make the response appear fast, and when the PC and projector process is fast, the response speed is judged to be sufficient, Therefore, it is possible to realize the image transmission method that can shift to the image quality priority mode and does not give the user an unpleasant feeling.

  According to a ninth aspect of the present invention, the display flag selection and addition step selects whether or not to add a display flag depending on whether or not the image displayed by the image generation device is continuously changing. Depending on whether the screen on the PC is a moving image or a still image, it can automatically switch between the speed priority mode with priority on response speed and the image quality priority mode with priority on screen accuracy. It is possible to realize an image transmission method that does not cause discomfort to the user.

  As described above, according to the present invention, an image transmission system and method that does not cause discomfort to the user is realized by automatically switching between a speed priority mode with priority on response speed and an image quality priority mode with priority on screen accuracy. can do.

  When the PC or projector process is slow, the speed priority mode is automatically selected to make the response appear fast. When the PC and projector process is fast, the response speed is judged to be sufficient, Automatically switch to the image quality priority mode, and the speed priority mode with priority to response speed and the image quality priority mode with priority to screen accuracy are automatically selected depending on whether the screen on the PC is a moving image or a still image. An image transmission system that can be switched automatically can be realized.

  The best mode for carrying out the present invention will be described below with reference to FIGS.

(Embodiment 1)
First, an image transmission system according to Embodiment 1 of the present invention will be described. FIG. 1 is a diagram showing an external configuration of the image transmission system according to the first embodiment.

  This transmission system is a system that transmits a screen displayed on the display device of the PC 100 from the PC 100 to the projector 200 and projects the received screen on the screen 20 by the projector 200. The PC 100 stores a wireless LAN chip. A wireless LAN card 10 is attached, thereby transmitting an image signal to the projector 200 via the wireless LAN.

  FIG. 2 is a block diagram showing hardware configurations of the PC 100 and the projector 200 that constitute the image transmission system according to the first embodiment.

  As shown in FIG. 2, the PC 100 receives an instruction signal based on a user operation from an input device such as a CPU 101, a main memory 102, a storage device 103, a graphic chip 104, a VRAM 105, an output IF 106 keyboard 111 or a mouse 112 output to a display 110. And a network IF 108 that is an interface for communicating with the projector 200 and the server via a LAN or the like.

  The projector 200 includes a CPU 201, a main memory 202, a storage device 203, a graphics chip 204, a resize LSI 205, a VRAM 206, a network IF 207, and an output device 208.

  FIG. 3 is a block diagram illustrating functional configurations of the PC 100 and the projector 200 that configure the image transmission system according to the first embodiment.

  As illustrated in FIG. 3, the PC 100 includes a control unit 121, a display screen generation unit 122, an image capture unit 123, a PC communication unit 124, a display output unit 125, and a display flag generation unit 126 as functional components.

  The control unit 121 is a processing unit that controls each unit constituting the PC 100, and is realized by the CPU 101 and the main memory 102. For example, the control unit 121 outputs a screen generation instruction to the display screen generation unit 122 or displays a screen to the image capture unit 123. Instruct capture.

  Further, the control unit measures the processing time of each unit and controls whether or not the display flag generation unit 126 generates a display flag.

  The display screen generation unit 122 is a processing unit that acquires a screen generation instruction from the control unit 121 and generates a screen to be output to a display device such as a display, and is realized by the graphics chip 104, the VRAM 105, and the like.

  The image capture unit 123 is a processing unit that acquires a capture instruction from the control unit 121 and captures the screen generated by the display screen generation unit 122, and is realized by the graphics chip 104, the main memory 102, or the like. Further, the image capture unit 123 outputs the captured image to the PC communication unit 124 through the display flag generation unit 126 as a screen to be transmitted to the projector 200.

  The PC communication unit 124 is a processing unit that acquires a transmission screen from the image capture unit 123 through the display flag generation unit 126, compresses and packetizes the transmission screen, and transmits the transmission screen to the projector 200. The PC communication unit 124 is realized by the CPU 101, the network IF 108, and the like. .

  The display output unit 125 is a processing unit that acquires the output screen generated by the display screen generation unit 122 and outputs it to the display device, and is realized by the output IF 106.

  The projector communication unit 221 is a processing unit that receives a compressed and packetized transmission screen from the PC communication unit 124 and passes data to the image expansion unit 223, and is realized by the CPU 201, the network IF 207, and the like.

  The image decompression unit 223 decompresses data passed from the projector communication unit 221. This is realized by the CPU 201, the main memory 202, and the like.

  The control unit 224 is a processing unit that controls each unit constituting the projector 200, and is realized by the CPU 201 and the main memory 202. For example, the control unit 224 instructs expansion of the image expansion unit 223 and controls display timing of the display output unit 222. I do.

  The display output unit 222 is a processing unit that acquires an image from the image expansion unit and outputs it on the screen, and includes an output device 208, a resize LSI 205, and a VRAM 206.

  The timing control of the display output unit is, for example, by outputting the image expanded by the image expansion unit 223 to the main memory 202, and if the expanded image has a display flag, outputting it to the VRAM 206 having a display screen. realizable.

  Next, a processing procedure of the image transmission system according to the first embodiment will be described.

  4 and 5 are sequence diagrams showing processing of the PC 100 and the projector 200. FIG.

  First, FIG. 4 will be described. When the PC 100 is activated, first, the performance of the CPU 101 of the PC 100 is measured (S41). The result obtained by the performance measurement is compared with a preset threshold value to determine the operation mode (S42). As an example of this performance measurement method, there is a method of measuring a processing time of a calculation routine or a compression routine prepared in advance and comparing it with a threshold value.

  The sequence diagram shown in FIG. 4 shows a sequence when the performance of the CPU 101 is higher than the set threshold value. In this case, the image quality priority mode is operated. Details of the image quality priority mode will be described later.

  After the threshold determination, the image displayed on the PC 100 is captured (S43). The image is divided in the horizontal direction by a preset number of divisions (S44). Each of the divided images is compressed by, for example, JPEG compression (S45, S46, S47). The compressed image is transmitted to the projector 200 when the compression is completed, and the projector starts expansion from the time when the data is received (S49, S50, S51). The PC 100 adds a display flag only once after creating the last compressed data (S48). The projector 200 receives and expands the data with the last display flag added, and displays it (S52).

  Next, FIG. 5 will be described. FIG. 5 shows a sequence when the performance of the CPU 101 is lower than the set threshold value. In this case, it operates in the speed priority mode. Details of the speed priority mode will be described later.

  Similar to the description of FIG. 4, the performance of the CPU 101 is measured in step S61 and compared with a preset threshold value in step S62 for determination. Thereafter, the image displayed on the PC 100 is captured (S63) and divided (S64).

  The divided image is compressed by, for example, JPEG compression (S65, S67, S69), but here, a display flag is added to all the compressed data (S66, S68, S70). The divided and compressed data is transmitted immediately after compression and flag addition, and is expanded by the projector 200 (S71, S73, S75). In this case, since the display flag is added to all, display is performed every time the image is expanded.

  6 to 10 are schematic diagrams for explaining the image quality priority mode and the speed priority mode.

  FIG. 6 shows the PC 100, and it is assumed that a PC screen 301 and figures 302, 303, and 304 are newly displayed on the PC screen 301. In this example, the screen 301 is divided and compressed in the horizontal direction from region 1 to region 4.

  7 to 10 are diagrams showing display transitions of the projector. A broken line 306 in FIGS. 7 to 10 indicates the last line that has already been displayed.

  In PC100, it divides | segments into the area | region 1, the area | region 2, the area | region 3, and the area | region 4, and compresses in order. First, the area 1 is compressed, and a display flag is added and transmitted to the projector 200. FIG. 7 shows the display of the projector at that time. Next, the area 2 is compressed, added with a display flag, and transmitted to the projector 200. FIG. 8 shows the display of the projector at that time. Similarly, when the areas 3 and 4 are compressed and transmitted, the display on the projector transitions to the states shown in FIGS. Thus, in the case of the sequence of FIG. 5, an image in the middle of the display of the PC 100 is projected from the projector 200.

  On the other hand, in the case of the sequence of FIG. 4, the states of FIGS. 7 to 9 are stored in the internal main memory 202 and the VRAM 206, but are not displayed, so the user does not project until the state of FIG. You will see the screen.

  In this way, the states that can be seen differ depending on the sequences of FIGS. In the case of the sequence in FIG. 4, it takes time until the display is started, but since an intermediate stage of the screen cannot be seen, the image is not broken and accurate display can be performed. Therefore, this mode is set as the image quality priority mode. On the other hand, in the case of the sequence of FIG. 5, the time until the display start can be shortened, but the image appears to be broken in the middle, resulting in an inaccurate display. Therefore, this mode is set as a speed priority mode.

  With the above-described system, it is possible to control whether the intermediate stage until the display of the projector 200 is shown or not by controlling the display flag on the PC 100.

  That is, it is possible to control whether priority is given to the speed until the start of display or priority is given to an accurate image without screen breakage according to the state of the PC 100.

  With this system, in the case of a PC with a slow processing speed, a speed priority mode in which the speed until the start of display is prioritized can be set. . Further, when the PC processing speed is high, it is determined that the time until display start is sufficiently short, and the image quality priority mode without screen breakage can be set.

  In addition, this system can be used properly depending on whether the screen displayed on the PC is a moving image or a still image. As a method for determining a moving image and a still image, an example shown in a second embodiment described later can be used.

  If it is determined to be a moving image, the image quality priority mode is executed. If it is determined to be a still image, the speed priority mode sequence is executed. Usually, in the case of a moving image with continuous motion, an accurate image without screen breakage does not give the user an unpleasant feeling compared to the time that is displayed on the PC and then projected onto the projector. For example, in the case of a still image in which the entire screen is updated once per second, the discomfort does not occur as the time until the display starts is shorter than the screen cracking.

  As described above, according to this system, when the processing of the PC or the projector is slow, the speed priority mode is automatically selected to make the response appear fast, and when the processing of the PC and the projector is fast, the response is made. It is determined that the speed is sufficient, and automatically shifts to the image quality priority mode. Also, the speed priority mode that gives priority to the response speed depending on whether the screen on the PC is a moving image or a still image. And an image transmission system that does not cause discomfort to the user can be realized.

  In the present embodiment, an example in which the screen is divided only in the horizontal direction in accordance with the scan direction of the PC or projector has been described. However, the screen may be divided in both horizontal and vertical directions, and the present invention is not limited to this.

  Next, another example of switching between the image quality priority mode and the speed priority mode will be described in detail. FIG. 11 is a flowchart showing an example of switching between the image quality priority mode and the speed priority mode according to the processing speeds of the PC and the projector. In FIG. 11, step S81 is an activation step in which the PC 100 starts processing, S82 is an image capture step in which an image displayed on the PC 100 is acquired, step S83 is a division compression step in which the acquired image is divided and compressed, and step S84 is in step S84. A step of determining whether the image quality priority mode or the speed priority mode is present; step S85 is a step of determining whether the data to be processed is the last data among the divided compressed data; and step S86 is a step of adding a display flag to the divided compressed data; Step S87 is a step in which no display flag is added, Step S88 is a step of transmitting divided and compressed data and a display flag, Step S89 is a step of receiving and decompressing data in the projector 200, and Step S90 is whether or not there is a display flag. The Step S91 is a step of updating the screen image of the projector 200, step S92 is a step of determining whether or not the divided data is the last, step S93 measures the time from step S82 to step S92, and step S93. This is a step of measuring and holding the time each time the above process is performed.

  Whether or not the image quality priority mode or the speed priority mode is determined in step S84 is determined based on the processing time data measured in step S93, for example, in the case of 1 second or more, the speed priority mode, and in the case of less than 1 second, the image quality priority mode. And Thus, the speed priority mode can be set when the PC speed and the projector processing speed are low, and the image quality priority mode can be set when the processing speed is high. In the speed priority mode, a display flag is added to all the divided and compressed data, and in the image quality priority mode, a display flag is added only to the last data that has been divided and compressed. Thereby, in the speed priority mode, display update is performed in step S91 from the beginning of the divided and compressed data. In the image quality priority mode, the display update is not performed because the process does not pass through step S91 until the final divided compression data is received.

  Here, the speed priority mode and the image quality priority mode are switched between 1 second as a boundary. However, the speed priority mode and the image quality priority mode are not limited to 1 second, and may be 0.5 seconds or 2 seconds, for example.

  Further, although the configuration is such that the loop time is updated each time, the configuration may be such that the time is updated only once at startup and the speed priority mode and the image quality priority mode are switched according to the time. In that case, it is not always necessary to take in the image of the PC 100 and perform division compression, and the data prepared in advance may be divided and compressed, and the speed measurement method is not limited thereto.

(Embodiment 2)
Next, an image transmission method according to the second embodiment will be described.

  FIG. 12 is a flowchart for explaining the present embodiment. Steps S91 to S97 are processes of the PC 100, and steps S98 to S101 indicate the processes of the projector 200.

  Step S91 is an activation step in which the PC 100 starts processing, step S92 is an image capture step for acquiring an image displayed on the PC 100, step S93 is a division compression step for dividing and compressing the image acquired in step 92, and step S94 is Step S95 is a moving image / still image determination step for determining whether the acquired image is a moving image or a still image, and step S95 is a step of adding a display flag to all the divided and compressed data when it is determined as a still image, and step S96. Is a step of adding a display flag to the last data of the divided data when it is determined to be the moving image mode. Step S97 is a step of transmitting the divided and compressed data.

  Step S98 is a step in which the projector 200 receives and decompresses data from the PC 100. Step S99 is a step in which it is determined whether or not the received / expanded data has a display flag. Step S100 updates the display when there is a flag. Step S101 is a step of holding the decompressed data without updating the display.

  In this method, after acquiring an image in step S92, the image is divided and compressed in step S93 in the same manner as shown in FIG. At this time, the divided data is compressed in the order of region 1 to region 2, region 3, and region 4. If the divided and compressed data is determined to be a moving image in the moving image / still image determination in step S94, a display flag is added to the last data, that is, the data in region 4 among the divided data, and the other regions 1 to No display flag is added to the compressed data in area 3 (step S94). If it is determined that the image is a still image, a display flag is added to all the compressed data in the areas 1 to 4 (step S95). The determination of still images and moving images will be described later. The projector 200 operates in the speed priority mode for still images and the image quality priority mode for moving images by updating the display only when there is a flag after receiving and decompressing the data in step S98. In the case of a still image, since the change does not occur continuously, the screen breakage is not noticeable. Therefore, it is possible to give priority to the time from when the screen of the PC 100 changes until the display of the projector 200 changes, so that the user is not uncomfortable. In the case of a moving image, since it changes continuously, if it is displayed at an intermediate stage, it is easy to see a crack in the screen, which makes the user uncomfortable. If this method is used, in the case of moving image display, since the last data is not displayed until it is expanded, the user is not uncomfortable. In addition, since the moving image data is continuously changed, even when the time from when the screen of the PC 100 is switched to when the display of the projector 200 is changed is long, the user does not feel the waiting time and does not feel uncomfortable.

  Next, a method for determining a moving image / still image will be described.

  FIG. 13 is a flowchart for explaining an example of a moving image / still image determination method.

  In FIG. 13, step S111 is an image capture step for acquiring a PC image, step S112 is a step for comparing the acquired image with a previously acquired screen and calculating a change region, and step 113 is a comparison result change region. Step S114 is a step for detecting whether there is a change area in Step S113, and a step for detecting whether the change is continuous twice or more. Step 115 is a change if the change is continuous twice or more. Step 116 for calculating the position of the changed region, step 116 is a step for determining whether or not the changed region calculated two times or more in step 115 is the same position. Step S117 indicates that the determination result is the moving image mode, and step S118 indicates that the determination result is the still image mode.

  According to this method, if there is no change area, the still image mode is determined in step S113. If there is a change area, if it is not continuous, the still image mode is determined in step S114. Even if it is continuously changing, if the area is in a different position, the still image mode is determined in step S116. Conversely, if a continuous change is made at the same position, it can be determined as a moving image. Thereby, it is possible to determine whether the screen displayed on the PC 100 is a moving image by a simple method.

  Note that in this embodiment, an example of a method for determining a moving image and a still image is shown, and it is possible to more simply determine a moving image and a still image without performing the processing of step S115 and step S116. . It is also possible to determine whether or not an application such as a video player is operating on the PC 100, or to determine whether or not the display of the operating position of the video player has changed. It is not a thing.

  In the present embodiment, the method of switching between the speed priority mode and the video priority mode based on the determination of the moving image and the still image has been described. However, as in the first embodiment, according to the processing speed of the PC and the projector, It is also possible to switch between speed priority mode and video priority mode.

  As described above, according to the method of the present invention, the response speed and the accuracy of the screen can be automatically switched depending on whether the screen on the PC is a moving image or a still image. Alternatively, if the PC or projector process is slow, the speed priority mode is automatically selected to make the response appear fast, and if the PC and projector process is fast, the response speed is judged to be sufficient, It is possible to automatically shift to the image quality priority mode. Therefore, it is possible to realize an image transmission method that does not give the user unpleasant feeling.

  As described above, the image transmission system and the image transmission method according to the present invention have been described based on the respective embodiments, but the present invention is not limited to these embodiments.

  For example, in the above embodiment, the communication between the PC and the projector is based on the wireless LAN, but it goes without saying that the communication may be performed using a wired LAN, USB (Universal Serial Bus), IEEE 1394, or the like. .

  Further, although the projector has been described as the image projection device, a display device such as a PDP may be used.

  The image transmission system and the image transmission method according to the present invention can be applied to a system for transmitting an image from a PC or the like as an image generation apparatus to a projector or the like as an image projection apparatus, in particular, a presentation using a wireless projector or the like. It is suitable when performing.

The figure which shows the external appearance structure of the image transmission system in Embodiment 1 of this invention. FIG. 2 is a block diagram showing a hardware configuration of a PC and a projector constituting the image transmission system according to the first embodiment. FIG. 2 is a block diagram showing a functional configuration of a PC and a projector constituting the image transmission system according to the first embodiment. Sequence diagram for explaining the operation in the image quality priority mode in the first embodiment Sequence diagram for explaining the operation in the speed priority mode in the first embodiment External view for explaining screen division in the first embodiment Schematic diagram showing the display state of the projector in the first embodiment Schematic diagram showing the display state of the projector in the first embodiment Schematic diagram showing the display state of the projector in the first embodiment Schematic diagram showing the display state of the projector in the first embodiment Flowchart for explaining a method for switching between image quality priority mode and speed priority mode in the first embodiment Flowchart for explaining an image transmission method according to Embodiment 2 of the present invention. Flowchart for explaining a method for switching between moving image mode and still image mode in the second embodiment Block diagram for explaining a conventional image transmission system

Explanation of symbols

10 Wireless LAN card 20 Screen 100, 501 PC
101, 201 CPU
102, 202 Main memory 103, 203 Storage device 104, 204 Graphics chip 105, 206 VRAM
106 Output IF
107 User IF
108, 207 Network IF
110 Display 111 Keyboard 112 Mouse 200 Projector 205 Resize LSI
301 PC display screen 305 Projection screen 502 PDP
511 Keyboard 512 Display (Liquid Crystal Display)
513 PC Card IF
514, 533 Image memory 515, 534 Control unit 520, 531 Wireless modem 532 Display (PDP)

Claims (12)

An image transmission system comprising an image generation device for generating an image and an image projection device for projecting an image transmitted from the image generation device,
The image generation device includes:
Image capture means for capturing images;
A division compression means for dividing and compressing a captured image for each region;
Display flag selection adding means for determining whether or not to add a display flag indicating whether or not to immediately display the data divided and compressed for each area;
A transmission means for transmitting each piece of compressed data;
With
The image projector is
Means for receiving the divided compressed data for each data;
Decompression means for decompressing the compression;
Updating means for determining whether a display flag exists for each data and updating the display after decompressing the data in which the display flag exists;
An image transmission system comprising: The display flag selection adding means is
The image transmission system according to claim 1, wherein whether to add a display flag is selected based on a processing speed of the image generation device or the image projection device. The display flag selection adding means is
2. The image transmission system according to claim 1, wherein whether or not to add a display flag is selected depending on whether or not the images displayed by the image generation device are continuously changing. The display flag selection adding means is
3. The method according to claim 1, wherein selection is made between adding a display flag to all of the divided compressed data or adding a display flag only to the last transmitted data among the divided compressed data. Image transmission system. The display flag selection adding means is
When the processing speed of the image generating device or the image projecting device is slower than a predetermined reference, a display flag is added to all the divided compressed data, and when the processing speed is faster than the predetermined reference, the divided compressed data The image transmission system according to claim 1, wherein a display flag is added only to data transmitted last. The display flag selection adding means is
If the image displayed by the image generation device does not change continuously, a display flag is added to all the divided and compressed data, and if the image changes continuously, the divided and compressed data 2. The image transmission system according to claim 1, wherein a display flag is added only to data transmitted last. An image transmission method for transmitting the image from an image generation device that generates an image to an image projection device that projects the image,
In the image generating apparatus,
An image capture step to capture the image;
A division compression step for dividing and compressing the captured image into regions;
A display flag selection addition step for determining whether or not to add a display flag indicating whether or not to immediately display the data divided and compressed for each region;
A transmission step for transmitting each piece of compressed data;
Including
In the image projection apparatus,
Receiving divided and compressed data for each data;
A decompression step to decompress the compression;
An update step for determining whether a display flag exists for each data and updating the display after decompressing the data for which the display flag exists;
An image transmission method comprising: The display flag selection adding step includes
8. The image transmission method according to claim 7, wherein whether to add a display flag is selected based on a processing speed of the image generation device or the image projection device. The display flag selection adding step includes
8. The image transmission method according to claim 7, wherein whether or not to add a display flag is selected depending on whether or not images displayed by the image generation device are continuously changing. The display flag selection adding step includes
9. The method according to claim 7, wherein a selection is made between adding a display flag to all of the divided and compressed data or adding a display flag only to the last data to be transmitted among the divided and compressed data. Image transmission method. The display flag selection adding step includes
When the processing speed of the image generating device or the image projecting device is slower than a predetermined reference, a display flag is added to all the divided compressed data, and when the processing speed is faster than the predetermined reference, the divided compressed data 8. The image transmission method according to claim 7, wherein a display flag is added only to data transmitted last. The display flag selection adding step includes
If the image displayed by the image generation device does not change continuously, a display flag is added to all the divided and compressed data, and if the image changes continuously, the divided and compressed data The image transmission method according to claim 7, wherein a display flag is added only to the last data to be transmitted.

Images