Image distribution system, distribution device, image distribution method, and program

Abstract

To provide a technique that enables a user to view an image output from a camera in an optimum size each time.SOLUTION: An image distribution system 1 includes a distribution device 10 that acquires an image output from a camera 30 and distributes it to a display terminal 20. On the basis of the image acquired from the camera 30, the distribution device 10 acquires size information regarding the size of the image and transmits the image and the size information to the display terminal 20. When the size information transmitted by the distribution device 10 is larger than the size of a display area 23 in which the image is displayed, the size information is not changed and the image corresponding to the size information is reduced to fit within the display area 23 and displayed in the display area 23. When the size information transmitted by the distribution device 10 is smaller than the size of the display area 23, the size information is not changed and the image corresponding to the size information is enlarged to a range that fits within the display area 23 and displayed in the display area 23.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an image distribution system, a distribution device, an image distribution method, and a program that acquires an image output from an imaging device and distributes it to a display terminal. [Background technology]

[0002] Patent Document 1 discloses a video distribution system in which a video distribution device distributes video data with image quality that matches the size of a window in which the video is displayed. This video distribution system includes a video distribution device that is pre-installed with a size-image-quality correspondence table, and a video compression device that compresses the same video from a camera at multiple image qualities. The size-image-quality correspondence table associates window sizes with image qualities that match those sizes. The video distribution device references the size-image-quality correspondence table to read and distribute video data with image quality that matches the window size from among the video data with multiple image qualities generated by the video compression device. The window size is resizable, and when the window size is enlarged, the video distribution device distributes video data with improved image quality. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-191949 Summary of the Invention [Problem to be solved by the invention]

[0004] The video distribution system of Patent Document 1 has a problem in that it cannot be operated unless the size-image-quality correspondence table and the video compression device are set in advance according to the camera settings.

[0005] An object of the present invention is to provide a technique that enables a user to view an image output from a camera in an optimal size each time. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention employs the following configuration. (1) An image distribution system according to one aspect of the present invention is an image distribution system including a distribution device that acquires an image output from an imaging device and distributes the image to a display terminal, wherein the distribution device acquires size information regarding the size of the image based on the image acquired from the imaging device and transmits the image and the size information to the display terminal, and when the size information transmitted by the distribution device is larger than the size of a display area of ​​the display terminal, the image corresponding to the size information is reduced to fit within the display area without changing the size information and displayed in the display area, and when the size information transmitted by the distribution device is smaller than the size of the display area, the image corresponding to the size information is enlarged to a range that fits within the display area without changing the size information and displayed in the display area.

[0007] According to this system, a distribution device transmits an image and size information to a display terminal, and the image distribution system uses the size information to display the image at an optimal size that fits the size of the display area.

[0008] (2) The delivery device may update the size information at predetermined time intervals, and the image delivery system may display the image in the display area based on the updated size information.

[0009] According to this, the size information is updated at a predetermined time interval, so that when, for example, the camera settings are changed, the image distribution system can display the image output from the camera after the settings are changed at an optimal size that fits the size of the display area in accordance with the update.

[0010] (3) The distribution device may also acquire a video as the image and update the size information each time a predetermined frame of the video is acquired, and the image distribution system may display the video in the display area based on the updated size information.

[0011] According to this, the size information is updated each time the distribution device acquires a predetermined frame. As a result, if, for example, the camera settings are changed, the image distribution system can display the image output from the camera after the setting change at an optimal size that matches the size of the display area in accordance with the update.

[0012] (4) Furthermore, the imaging device may include at least a first imaging device and a second imaging device, and the distribution device may acquire first size information regarding the size of a first image acquired from the first imaging device based on the first image, and acquire second size information regarding the size of a second image acquired from the second imaging device based on the second image.

[0013] According to this, the distribution device can acquire at least first size information and second size information, and the image distribution system can display the first image at an optimal size to fit the size of the display area using the first size information, and can display the second image at an optimal size to fit the size of the display area using the second size information.

[0014] (5) The distribution device may also include a selection means for selecting one of the first and second imaging devices, and when the first imaging device is selected by the selection means, the distribution device may transmit the first image and the first size information to the display terminal, and when the second imaging device is selected by the selection means, the distribution device may transmit the second image and the second size information to the display terminal.

[0015] According to this, the distribution device transmits the image and size information of the selected imaging device to the display terminal, and the image distribution system can display the image of the selected imaging device at an optimal size that fits the size of the display area by using the size information of the selected imaging device.

[0016] (6) Furthermore, the selection means may select one of the first and second imaging devices in response to a user's selection operation, and when the selection operation to select the second imaging device is performed while the first image is displayed in the display area of ​​a predetermined size, if the second size information is larger than the display area of ​​the predetermined size, the image distribution system may reduce the second image to fit within the display area without changing the second size information and display it in the display area of ​​the predetermined size, and if the second size information is smaller than the display area of ​​the predetermined size, the image may be enlarged to a range that fits within the display area without changing the second size information and display it in the display area of ​​the predetermined size.

[0017] According to this, when a second imaging device is selected while a first image is being displayed in a display area of ​​a predetermined size, the image distribution system can use the second size information to display the second image at an optimal size to fit the display area of ​​the predetermined size.

[0018] (7) The display terminal may also include a display area resizing means for changing the size of the display area in response to a user's resizing operation, and when the display area is enlarged by the display area resizing means, the image may be enlarged and displayed in the display area in response to the enlargement of the display area, and when the display area is reduced by the display area resizing means, the image may be reduced and displayed in the display area in response to the reduction of the display area.

[0019] This allows the user to change the size of the image by changing the size of the display area, so that the image can be displayed in a preferred size.

[0020] (8) Furthermore, a distribution device according to one aspect of the present invention is a distribution device that acquires an image output from an imaging device and distributes it to a display terminal, and includes: a size information acquisition means that acquires size information regarding the size of the image based on the image acquired from the imaging device; and a transmission means that transmits the image and the size information to the display terminal; and if the size information is larger than the size of a display area of ​​the display terminal, the size information is not changed and the image corresponding to the size information is reduced to fit within the display area and displayed in the display area; and if the size information is smaller than the size of the display area, the size information is not changed and the image corresponding to the size information is enlarged to a range that fits within the display area and displayed in the display area.

[0021] This provides the same effects as the image distribution system described above.

[0022] (9) Furthermore, a distribution device according to one aspect of the present invention may be a distribution device that acquires an image output from an imaging device and distributes it to a display terminal, and may include: a size information acquisition means that acquires size information regarding the size of the image based on the image acquired from the imaging device; a display area information receiving means that receives display area information regarding the size of the display area of ​​the display terminal from the display terminal; a reduction ratio calculation means that, if the size information is larger than the size of the display area, calculates a reduction ratio for reducing the image to fit within the display area based on the size information and the display area information; a magnification ratio calculation means that, if the size information is smaller than the size of the display area, calculates a magnification ratio for enlarging the image to a range that fits within the display area based on the size information and the display area information; and a transmission means that transmits the image and either the reduction ratio or the magnification ratio to the display terminal.

[0023] This allows the display terminal to display the image at an optimal size that matches the size of the display area by using the image transmitted from the distribution device and the reduction ratio or enlargement ratio.

[0024] (10) Furthermore, an image delivery method according to one aspect of the present invention is an image delivery method for acquiring an image output from an imaging device and delivering it to a display terminal, the image delivery method including: an image acquisition unit acquiring the image output from the imaging device; a size information acquisition unit acquiring size information regarding the size of the image based on the image acquired by the image acquisition unit; a transmission unit transmitting the image and the size information to the display terminal; if the size information transmitted by the transmission unit is larger than the size of a display area of ​​the display terminal, reducing the image corresponding to the size information to fit within the display area without changing the size information and displaying it in the display area; and if the size information transmitted by the transmission unit is smaller than the size of the display area, enlarging the image corresponding to the size information to a range that fits within the display area without changing the size information and displaying it in the display area.

[0025] This provides the same effects as the image distribution system described above.

[0026] (11) Furthermore, a program according to one aspect of the present invention is a program executed on a computer of a distribution device that acquires an image output from an imaging device and distributes it to a display terminal, and causes the computer to function as a size information acquisition means that acquires size information regarding the size of the image based on the image acquired from the imaging device, and a transmission means that transmits the image and the size information to the display terminal, and when the size information is larger than the size of a display area of ​​the display terminal, the size information is not changed and the image corresponding to the size information is reduced to fit within the display area and displayed in the display area, and when the size information is smaller than the size of the display area, the size information is not changed and the image corresponding to the size information is enlarged to a range that fits within the display area and displayed in the display area.

[0027] This provides the same effects as the image distribution system described above.

[0028] The present invention can be realized as a recording medium on which the program is recorded, or as information, data, or signals representing the program. The program, information, data, and signals may be distributed via a communication network such as the Internet. [Effects of the Invention]

[0029] According to the present invention, it is possible to allow a user to view an image output from a camera at an optimal size each time. [Brief explanation of the drawings]

[0030] [Figure 1] An explanatory diagram showing an example of the overall configuration of an image distribution system 1. [Figure 2] 1 is a flowchart showing an example of a distribution device process executed by the distribution device 10. [Figure 3] 10 is a flowchart showing an example of a display terminal process executed in the display terminal 20. [Figure 4] FIG. 10 is an explanatory diagram illustrating an example of the relationship between the timing at which size information is updated in the distribution device 10 and the timing at which the enlargement / reduction ratio is updated in the display terminal 20. [Figure 5] FIG. 10 is an explanatory diagram illustrating an example of a display mode (B to D) when an image from a FullHD camera is displayed from a state (A) in which an image from the camera is not displayed, in a case where a value indicating FullHD is set as the initial value of size information. [Figure 6] FIG. 10 is an explanatory diagram illustrating an example of a display mode (B to E) when an image from an HD camera is received from a state (A) in which an image from the camera is not displayed, in a case where a value indicating Full HD is set as the initial value of size information. [Figure 7] FIG. 10 is an explanatory diagram illustrating an example of a display mode (B to D) when an image from a FullHD camera or an HD camera is delivered from a state (A) in which an image from the camera is not displayed, in a case where a value indicating an HD camera is set as the initial value of the size information. [Figure 8] FIG. 10 is an explanatory diagram for explaining examples of display modes (B to D) when a user switches from a state (A) in which an image from a Full HD camera is being displayed to an HD camera or another Full HD camera. [Figure 9] FIG. 10 is an explanatory diagram for explaining examples of display modes (B to D) when a user switches from a state (A) in which an image from an HD camera is being displayed to a Full HD camera or another HD camera. [Figure 10] FIG. 10 is an explanatory diagram showing an example of the overall configuration of an image delivery system 1 in another embodiment in which the enlargement / reduction ratio is updated by the delivery device 10. [Figure 11] A flowchart showing an example of a distribution device process executed by the distribution device 10 in another embodiment in which the enlargement / reduction ratio is updated by the distribution device 10. [Figure 12] Detailed flowchart of the distribution device calculation and transmission process in step SH208 of FIG. 11 DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, an embodiment of the present invention will be described with reference to the drawings as appropriate.

[0032] The embodiments described below each illustrate a preferred specific example of the present invention. The numerical values, shapes, materials, components, component placement and connection configurations, steps, and step order shown in the following embodiments are merely examples and are not intended to limit the present invention. Furthermore, among the components in the following embodiments, components that are not described in the independent claims that represent the highest concept of the present invention will be described as optional components that constitute a more preferred embodiment. Note that identical components will be assigned the same reference numerals, and descriptions thereof may be omitted.

[0033] [Example of schematic configuration of image distribution system 1] An example of the schematic configuration of the image delivery system 1 will be described with reference to Fig. 1. Fig. 1 is an explanatory diagram showing an example of the overall configuration of the image delivery system 1. The image delivery system 1 is installed in, for example, a factory, a facility, an office, a parking lot, a park, a residence, etc.

[0034] 1, the image distribution system 1 includes a distribution device 10, a display terminal 20, and a camera 30. A user of the display terminal 20 accesses the distribution device 10 using, for example, a browser, and uses the browser to view images generated by the camera 30.

[0035] In this embodiment, camera 30 is an imaging device that captures the surroundings and generates images (frames) that serve as the basis for a video. Camera 30 compresses the generated images based on a predetermined standard and transmits them to distribution device 10. Camera 30 may be, for example, a network camera, a USB camera, or an analog camera. In this embodiment, camera 30 is described as including multiple cameras (30a to 30d), but camera 30 may include at least one camera (e.g., 30a). Note that, hereinafter, multiple cameras are collectively referred to as "camera 30," and a specific camera (e.g., camera 30a) among the multiple cameras 30 is referred to as camera 30a. Each camera 30 may be the same type of camera or different types of cameras. Furthermore, camera 30 may transmit images using RTP (Real-time Transport Protocol) or UDP. Furthermore, the resolutions of each camera 30 may be the same or different. For example, the plurality of cameras 30 includes a camera that captures images with an HD resolution and a camera that captures images with a Full HD resolution.

[0036] The camera 30 included in the image distribution system 1 may be any type, and may include a 4K camera with a 4K resolution or an 8K camera with an 8K resolution. The camera 30 may also be an imaging device that periodically generates and transmits still images at preset time intervals (for example, every second).

[0037] The images that the camera 30 transmits to the distribution device 10 include, for example, I frames (key frames), P frames (difference frames), and B frames. I frames are frames created without using inter-frame prediction. I frames contain all information about the frame in question, and the frame can be displayed by itself. P frames are frames created based on the difference with the previous frame (I frame or P frame, hereinafter referred to as the "reference frame"). Since P frames contain only information about the difference with the reference frame, the frame in question can be displayed based on both the P frame and the reference frame. B frames are frames created based on the difference with the previous and next reference frames in question. Since B frames contain only information about the difference with the reference frame, the frame in question can be displayed based on both the B frame and the reference frame.

[0038] The camera 30 is connected to the distribution device 10 via an IP network. The camera 30 and the distribution device 10 may be connected via a wired connection or wirelessly. The camera 30 and the distribution device 10 may also be connected via a local area network (LAN) or via the Internet.

[0039] The camera 30 outputs the generated image to the distribution device 10 via an IP network. In this embodiment, the frame rate of the camera 30 is described as 30 frames per second (fps), but it may be 20 fps or 40 fps.

[0040] 1 shows an example in which the image delivery system 1 is equipped with a total of four cameras 30. Note that the number of cameras 30 equipped in the image delivery system 1 is arbitrary, and may be, for example, one or 100.

[0041] The distribution device 10 acquires an image output from the camera 30. The distribution device 10 is connected to the display terminal 20 via an IP network so that they can communicate with each other, and distributes (transmits) the image acquired from the camera 30 to the display terminal 20. The distribution device 10 and the display terminal 20 may be connected via a wired connection or wireless connection. Furthermore, the distribution device 10 and the display terminal 20 may be connected via a LAN or via the Internet.

[0042] The distribution device 10 of this embodiment acquires size information about the size of an image based on an image (specifically, for example, the above-mentioned I-frame) acquired from the camera 30. Then, the distribution device 10 distributes (transmits) the acquired size information to the display terminal 20 via an IP network. The processing of the distribution device 10 will be described in detail later.

[0043] The size information is, for example, information indicating the resolution of an image. Note that the size information may be, for example, a symbol (or number) indicating a common name for the resolution, such as HD, FullHD, or 4K, or may be information indicating the number of vertical and horizontal pixels of an image. The size information may also be information including the number of pixels in either the vertical or horizontal direction of an image and the aspect ratio.

[0044] 1, the distribution device 10 includes an image acquisition unit 11, an image storage unit 12, a size information acquisition unit 13, a size information storage unit 14, and an image / size information transmission unit 15. Each of the above units included in the distribution device 10 is realized by the distribution device 10 including hardware such as a processor, a storage device (including memory), and a communication module, and by the processor executing a predetermined program stored in the storage device.

[0045] The image acquisition unit 11 is connected to the cameras 30 via an IP network, acquires images from the cameras 30, and stores them in the image storage unit 12. In this embodiment, the image acquisition unit 11 always acquires images from each of the multiple cameras 30, regardless of whether or not there is a request from the display terminal 20 for distribution of an image from the camera 30 (hereinafter also referred to as an image distribution request), and stores the received images in the image storage unit 12 for each camera 30. When the image acquisition unit 11 receives an image distribution request from the display terminal 20, it transmits the image of that camera to the image / size information transmission unit 15. Note that the distribution device 10 does not necessarily have to include the image storage unit 12.

[0046] The size information acquisition unit 13 acquires size information based on the image from the camera 30 acquired by the image acquisition unit 11, and stores the size information in the size information storage unit 14. Specifically, the image acquisition unit 11 acquires size information every time it acquires a predetermined image (specifically, for example, the above-mentioned I frame) from the images (video) from the camera 30, and stores the size information in the size information storage unit 14 in association with the camera 30.

[0047] The size information storage unit 14 can store one piece of size information corresponding to one camera 30. The size information storage unit 14 may also be able to store a plurality of pieces of size information corresponding to one camera 30. For example, if the camera 30 supports a plurality of resolutions, the size information storage unit 14 may store a plurality of pieces of size information as the size information of that camera 30.

[0048] The image storage unit 12 and the size information storage unit 14 may be configured by one storage device (e.g., a hard disk, a nonvolatile memory, etc.) or by multiple storage devices. Furthermore, the image storage unit 12 and the size information storage unit 14 may be configured by an external storage device connected to the distribution device 10 via a network different from that of the distribution device 10.

[0049] In response to an image distribution request from the display terminal 20, the image and size information transmission unit 15 transmits to the display terminal 20 the image from the camera 30 acquired by the image acquisition unit 11 and size information of the image read from the size information storage unit 14. Here, if multiple cameras 30 are connected to the distribution device 10, the image distribution request from the display terminal 20 may include selected camera information indicating information about the camera 30 selected by the user of the display terminal 20. The image and size information transmission unit 15 transmits to the display terminal 20 the image acquired from the camera 30 indicated by the selected camera information and size information of the image. Note that the image and size information transmission unit 15 may also transmit to the display terminal 20 the image read from the image storage unit 12 and size information of the image read from the size information storage unit 14 in response to a request from the user of the display terminal 20.

[0050] The distribution device 10 does not necessarily have to include the image storage unit 12 and the size information storage unit 14. In such a case, the image / size information transmission unit 15 temporarily stores the image output from the camera 30 and the size information acquired from the image in a memory included in the distribution device 10, or transmits the image and size information directly to the display terminal 20 without storing them.

[0051] Display terminal 20 also receives the image and size information transmitted from distribution device 10, and displays the received image in display area 23 on a browser on a display unit (not shown), such as a display. Needless to say, the size of display area 23 directly depends on the size of the browser window on the display unit, and is uniquely determined by freely changing the size of the window by the user using a mouse or the like.

[0052] Specifically, display terminal 20 includes image and size information receiving unit 21, zoom display processing unit 22, display area 23, selected camera information transmitting unit 24, and input unit 25. In this embodiment, when a user of display terminal 20 accesses distribution device 10 using a browser, image and size information transmitting unit 15 transmits a program written in a script language that runs on the browser to display terminal 20. The processor of display terminal 20 executes the program, thereby realizing each of the above-mentioned units.

[0053] The image and size information receiving unit 21 receives images and size information transmitted from the distribution device 10. Specifically, the image and size information receiving unit 21 receives images transmitted in streaming format from the distribution device 10, and also receives size information from the distribution device 10 at predetermined time intervals (e.g., once every one second to every several tens of seconds). Note that the image and size information receiving unit 21 may receive size information every time an I frame is received.

[0054] The scaling display processing unit 22 calculates the "magnification ratio" or "reduction ratio" (hereinafter referred to as "scaling-reduction ratio") of the image received from the distribution device 10 based on the size information received from the distribution device 10 and the size of the display area 23. Then, the scaling display processing unit 22 enlarges or reduces the image received from the distribution device 10 as needed based on the scaling ratio, and displays it in the display area 23. Note that if the scaling display processing unit 22 determines that scaling is not necessary based on the received size information and the size of the display area 23, it displays the received image in the display area 23 without scaling it. In this way, the scaling display processing unit 22 displays the image received from the distribution device 10 in the display area 23 at an "optimal size."

[0055] In this embodiment, the "size of the display area 23" refers to information indicating the size of the display area 23 that displays an image received from the distribution device 10. The "size" may be information indicating the number of vertical and horizontal pixels, or information including a predetermined number of pixels in either the vertical or horizontal direction and an aspect ratio. For example, if the program executed by the processor of the display terminal 20 is written in JavaScript (registered trademark), the display terminal 20 can obtain the height of the display area 23 using the document.documentElement.clientHeight function and the width of the display area 23 using the document.documentElement.clientWidth function. The display terminal 20 may obtain the height of the display area 23 from the innerHeight attribute and the width of the display area 23 from the innerWidth attribute.

[0056] Furthermore, the "magnification ratio" refers to the ratio at which an image is enlarged to the maximum extent possible so that the entire image fits within the display area 23. The "reduction ratio" refers to the ratio at which an image is reduced to the minimum extent possible so that the entire image fits within the display area 23.

[0057] In this embodiment, the "optimal size" refers to a size in which, when an image is displayed in the display area 23, the image is not cut off or no excess space is left in the display area 23. When the image received from the distribution device 10 is enlarged or reduced by the scaling display processing unit 22 to the "optimal size," the aspect ratio of the image is the same as the aspect ratio of the image received from the distribution device 10. In this embodiment, because the aspect ratio of the image received from the distribution device 10 differs from the aspect ratio of the display area 23, when the image is enlarged to the maximum (or reduced to the minimum) and displayed in the display area 23 at the "optimal size," blank areas in the display area 23 where no image is displayed may occur.

[0058] If the aspect ratio of the image received from distribution device 10 differs from the aspect ratio of display area 23, display terminal 20 may perform processing to adjust the size of display area 23 so that the aspect ratio of display area 23 matches the aspect ratio of the image. This prevents part of display area 23 from being cut off or becoming blank when an image enlarged or reduced by enlargement / reduction display processing unit 22 is displayed in display area 23.

[0059] Furthermore, when the aspect ratio of the image received from distribution device 10 differs from the aspect ratio of display area 23, display terminal 20 may enlarge (or reduce) the image at different aspect ratios so that the aspect ratio of the image matches the aspect ratio of display area 23. As a result, regardless of whether the aspect ratio of the image received from distribution device 10 differs from the aspect ratio of display area 23, when the image enlarged or reduced by enlargement / reduction display processing unit 22 is displayed in display area 23, part of display area 23 is not cut off or becomes blank.

[0060] Based on a user's input to the input unit 25, the selected camera information transmitting unit 24 transmits to the distribution device 10 selected camera information indicating the camera selected by the user.

[0061] The input unit 25 is an input device for inputting information to the display terminal 20, and includes, for example, a mouse, a keyboard, a touch panel, and buttons. The input unit 25 is used for a selection operation in which a user selects one of the cameras 30 connected to the distribution device 10, and a change operation in which a user changes the size of the display area 23.

[0062] For example, when a user accesses the distribution device 10 (specifically, the image and size information transmission unit 15) using a browser on the display terminal 20, a selection screen is displayed for selecting one of the multiple cameras 30. When a selection operation to select one of the multiple cameras 30 is performed on the selection screen, the selected camera information is transmitted from the selected camera information transmission unit 24 to the distribution device 10, and then the image and size information from the selected camera 30 are transmitted from the image and size information transmission unit 15. For example, the distribution device 10 may assign a camera number to identify each camera 30, and a list of camera numbers may be displayed on the selection screen displayed on the browser of the display terminal 20, from which one of the cameras may be selected by a selection operation. Then, an image from the selected camera is displayed in the display area 23 of the browser on the display terminal 20. Furthermore, even when an image from the selected camera 30 is displayed on the browser of the display terminal 20, a selection operation to select another camera is possible. For example, when an image from camera 30a is displayed in the display area 23, if a selection operation to select another camera 30b is performed, the image from camera 30b is displayed in the display area 23.

[0063] 2 is a flowchart showing an example of distribution device processing executed by distribution device 10. Note that FIG. 2 mainly describes processing related to image distribution to display terminal 20, and omits the processing of storing images from each camera 30 in image storage unit 12 described above.

[0064] As illustrated in step SH101 of FIG. 2, the distribution device 10 first initializes the size information and selected camera information of each camera 30.

[0065] In this embodiment, the size information of each camera 30 is initially set to, for example, a value indicating FullHD. Note that the initial size information may be any value.

[0066] Next, the distribution device 10 performs a selection screen transmission process (step SH102). Specifically, the distribution device 10 determines whether or not there has been access from the browser of the display terminal 20, and if there has been access, transmits a page (e.g., an HTML file) for displaying a selection screen on the browser of the display terminal 20. Note that in the selection screen transmission process, before the distribution device 10 transmits the selection screen to the display terminal 20, authentication of a user who uses the image distribution system may be performed between the distribution device 10 and the display terminal 20.

[0067] After step SH102, the distribution device 10 (specifically, the image / size information transmission unit 15) determines whether or not selected camera information has been received from the display terminal 20 (step SH103). If the result of step SH103 is YES, the image / size information transmission unit 15 updates the contents of the selected camera information from the initialized contents to the contents indicated by the received selected camera information (step SH104).

[0068] If the process of step SH104 has been executed, or if the result of step SH103 is NO, the distribution device 10 (specifically, the image acquisition unit 11) acquires an image from the camera 30 indicated by the selected camera information (step SH105).

[0069] Next, the distribution device 10 transmits the image from the camera 30 acquired in step SH105 to the display terminal 20 (step SH106). Alternatively, the distribution device 10 transmits to the display terminal 20 an image from the camera 30 indicated by the selected camera information stored in the image storage unit 12. Note that when the distribution device 10 first transmits an image from the camera 30 indicated by the selected camera information to the display terminal 20, the distribution device 10 transmits the size information of the camera 30 initialized in step SH101 along with the image.

[0070] Following step SH106, the distribution device 10 (specifically, the size information acquisition unit 13) determines whether the image acquired in step SH105 is an I frame (step SH107). If the result in step SH107 is YES, the size information acquisition unit 13 acquires size information based on the I frame and stores it in the size information storage unit 14 (step SH108).

[0071] If the processing of step SH108 has been performed, or if the answer is NO in step SH107, the distribution device 10 determines whether or not there has been a request from the display terminal 20 to send size information of the camera 30 indicated by the selected camera information (specifically, a request to distribute an image) (step SH109).

[0072] If the answer is YES in step SH109, ​​the distribution device 10 transmits the size information of the camera 30 indicated by the selected camera information stored in the size information storage unit 14 to the display terminal 20 via the image / size information transmission unit 15 (step SH110).

[0073] If the result of step SH109 is NO, or if the processing of step SH110 has been executed, the distribution device 10 advances the processing to step SH103.

[0074] In this embodiment, a configuration is adopted in which size information can be acquired based on an image output from the camera 30 indicated by the selected camera information.

[0075] In another embodiment, the distribution device 10 may always acquire images from each camera 30 regardless of whether the user has selected a camera, and acquire size information for each camera 30 based on the always acquired images. In this way, the distribution device 10 can, for example, acquire size information for all cameras 30 connected to the distribution device 10 in advance and store the size information in the size information storage unit 14.

[0076] 3 is a flowchart showing an example of a display terminal process executed by the display terminal 20. The process shown in FIG. 3 is performed after the browser of the display terminal 20 is used to access the distribution device 10.

[0077] 3, the display terminal 20 first displays a selection screen. Specifically, the browser acquires the page of the selection screen from the distribution device 10 and displays the selection screen.

[0078] Next, display terminal 20 (specifically, selected camera information transmission unit 24) determines whether or not the user has performed a selection operation to select one of the multiple cameras 30 using input unit 25 (step ST102). If the result of step ST102 is YES, selected camera information transmission unit 24 updates the selected camera information to information indicating the camera selected by the user (step ST103).

[0079] If the processing of step ST103 has been executed, the display terminal 20 transmits the selected camera information to the distribution device 10 (step ST104). If the processing of step ST104 has been executed, or if the answer is NO in step ST102, the display terminal 20 (specifically, the image / size information receiving unit 21) receives an image from the camera 30 indicated by the selected camera information from the distribution device 10 (step ST105).

[0080] When display terminal 20 first receives an image from camera 30 indicated by the selected camera information, it receives the initial size information (e.g., information indicating Full HD) set for that camera 30. Display terminal 20 calculates the initial enlargement / reduction ratio based on that size information and the current size of browser display area 23, and stores it in memory.

[0081] Following step ST105, the display terminal 20 determines whether it is time to update the size information (step ST106). In this embodiment, the size information is updated at predetermined time intervals (for example, every 1 second) (T2 in FIGS. 4A and 4B, which will be described later, is 1 second).

[0082] If the answer is YES in step ST106, the display terminal 20 (specifically, the image / size information receiving unit 21) requests the size information of the camera 30 indicated by the selected camera information from the distribution device 10, and receives the size information from the distribution device 10 (step ST107).

[0083] If the answer is NO in step ST106, or if the process of step ST107 has been performed, the display terminal 20 acquires the current size of the display area 23 (step ST108).

[0084] Then, the display terminal 20 (specifically, the enlargement / reduction display processing unit 22) determines whether or not the size of the current display area 23 is smaller than the size information received in step ST107 (step ST109). If the answer is YES in step ST109, that is, if the size of the display area 23 (that is, the information indicating the screen size) is smaller than the size information, the enlargement / reduction display processing unit 22 calculates the reduction ratio of the image received in step ST105 based on the size information and the current size of the display area 23 (that is, updates the enlargement / reduction ratio: step ST110).

[0085] On the other hand, if the result of step ST109 is NO, the display terminal 20 (specifically, the enlargement / reduction display processing unit 22) determines whether or not the size of the display area 23 is larger than the size information (step ST111). If the result of step ST111 is YES, that is, if the size of the display area 23 is larger than the size information, the enlargement / reduction display processing unit 22 calculates the enlargement ratio of the image received in step ST105 based on the size information and the current size of the display area 23 (that is, updates the enlargement / reduction ratio: step ST112).

[0086] If NO in step ST111, that is, if the size information indicates the same size as the size of the display area 23, the display terminal 20 (specifically, the enlargement / reduction display processing unit 22) advances the process to step ST113.

[0087] If the processing of step ST110 is executed, if the answer is NO in step ST111, or if the processing of step ST112 is executed, the display terminal 20 (specifically, the zoom display processing unit 22) displays the image received in step ST105 in the browser display area 23 at a size based on the current zoom ratio (step ST113).

[0088] In this way, when the size information is updated or the size of display area 23 is updated, the enlargement / reduction rate is updated based on the size information and the size of display area 23. For example, when the selected camera information changes (when the selected camera is changed), if the size information of the changed camera differs from the size information of the camera before the change, display terminal 20 updates the enlargement / reduction rate based on the changed size information of the camera and the current size of display area 23 as the size information is updated in step ST106. Also, for example, if display area 23 is enlarged (or reduced) in response to a user's change operation while an image from camera 30 is being displayed, the image can be enlarged (or reduced if display area 23 is reduced) in accordance with the change in the size of display area 23 (see FIGS. 5(B) to (D) and FIGS. 6(C) to (E)).

[0089] If the process of step ST113 has been executed, the display terminal 20 advances the process to step ST102.

[0090] Next, with reference to FIG. 4, an example of the relationship between the timing at which the size information is updated in the distribution device 10 and the timing at which the size information is updated in the display terminal 20 will be described. In this embodiment, the size information in the distribution device 10 is updated in response to the distribution device 10 receiving an I frame. For example, if a 30 fps video has five I frames per second, the distribution device 10 updates the size information at intervals of 1 / 5 second (T1 in FIG. 4A is 1 / 5 second). In contrast, the size information in the display terminal 20 is updated at a predetermined time interval (every second in this embodiment) (T2 in FIG. 4A is 1 second). As such, in this embodiment, the size information in the distribution device 10 is updated at a fixed first time interval (T1), while the size information in the display terminal 20 is updated at a fixed second time interval (T2) that is longer than the first time interval. Therefore, when the selected camera information changes and the size information of the changed camera differs from the size information of the camera before the change, display terminal 20 maintains the size information of the camera before the change until the second time has elapsed since the previous update of the size information, and updates the enlargement / reduction ratio based on the size information of the camera before the change. Then, as the second time has elapsed since the previous update of the size information, display terminal 20 updates the size information to the size information of the changed camera, and updates the enlargement / reduction ratio based on the size information of the changed camera.

[0091] However, in the following case, for example, the time interval at which the distribution device 10 receives I frames is not constant, as shown in FIG. 4(B). -Videos that are supposed to be sent at 30fps may be dropped due to communication issues. - If the frame rate fluctuates. When communication quality changes over time, the distribution device 10 dynamically changes the I-frame interval in the video it acquires in response to changes in communication quality.

[0092] In the above case, the size information is updated at random time intervals in the distribution device 10. For example, if T1 in FIG. 4B is 1 / 5 second, the size information in the distribution device 10 is updated every 2 / 5 seconds (between a and c, between g and i, and between i and k), every 3 / 5 seconds (between c and f), or every 1 / 5 second (between f and g). In contrast, the size information in the display terminal 20 is updated at regular time intervals (T2 in FIG. 4B is 1 second).

[0093] 4A and 4B, distribution device 10 updates the size information every time an I frame is acquired, but this is not limited to this. The size information may be updated every two or three times an I frame is acquired. Alternatively, the update interval for the size information may be determined first, and the size information may be updated using the size information of the I frame acquired immediately after the update interval has arrived.

[0094] On the other hand, the time interval at which the size information on the display terminal 20 is updated may be any length. For example, the size information on the display terminal 20 may be updated every 15 seconds, every 60 seconds, or at a time interval shorter than the time interval at which the size information on the distribution device 10 is updated. Furthermore, the size information on the display terminal 20 may be updated in conjunction with an update of the size information on the distribution device 10. In this case, the size information on the display terminal 20 may be updated in conjunction with an update of the size information on the distribution device 10, but may not be updated at the above-described second time interval (T2). Alternatively, the size information on the display terminal 20 may be updated at the above-described second time interval (T2) in addition to being updated in conjunction with an update of the size information on the distribution device 10.

[0095] Next, with reference to Fig. 5 to Fig. 9, a specific example of the display area 23 of the display terminal 20 when a video is viewed in the image distribution system 1 will be described. Fig. 5 is an explanatory diagram for explaining examples of display modes (B to D) when an image from a FullHD camera is displayed after an image from the camera is not displayed (A) in a case where a value indicating FullHD is set as the initial value of the size information. It is assumed that the size of the display area 23 does not change between Fig. 5(A) and Fig. 5(B).

[0096] Fig. 5(A) illustrates an example of the state of display area 23 when no image from the camera is displayed and the size information is set to a value (initial value) indicating FullHD. As illustrated in Fig. 5(A), when no image from the camera is displayed, the entire display area 23 is blank. Note that display area 23 may be the entire browser window or a partial area within the browser window. Only display area 23 is shown in the figure.

[0097] 5(B) illustrates an example of the state immediately after an image from a Full HD camera is distributed from distribution device 10 in the state illustrated in FIG. 5(A). As illustrated in FIG. 5(B), the image from the Full HD camera is displayed at a size optimal for display area 23 of display terminal 20. That is, based on the initial size information and the size of display area 23, the image from the camera is enlarged or reduced to fit the size of display area 23 and displayed.

[0098] Fig. 5(C) illustrates an example of a situation where the user enlarges the size of display area 23 in the state illustrated in Fig. 5(B). As illustrated in Fig. 5(C), the image from the Full HD camera is enlarged and displayed while maintaining an optimal size in accordance with the enlargement of display area 23. Note that at this time, the Full HD camera remains connected to distribution device 10, the selected camera information has not been changed, and distribution device 10 has not changed the size information.

[0099] On the other hand, Fig. 5(D) illustrates an example of a situation where the user reduces the size of display area 23 in the state illustrated in Fig. 5(B). As illustrated in Fig. 5(D), the image from the Full HD camera is displayed reduced while maintaining an optimal size in accordance with the reduction of display area 23. Note that at this time, the Full HD camera remains connected to distribution device 10, the selected camera information has not been changed, and distribution device 10 has not changed the size information.

[0100] Next, Fig. 6 is an explanatory diagram for explaining examples (B to E) of display modes when an image from an HD camera is received from a state (A) in which the image from the camera is not displayed, when a value indicating FullHD is set as the initial value of the size information. Note that the size of display area 23 does not change between Figs. 6(A) to 6(C).

[0101] FIG. 6(A), like FIG. 5(A), illustrates the state of the display area 23 when no image from the camera is displayed and the size information is set to the initial value (equivalent to Full HD). FIG. 6(B) illustrates the state immediately after an image from an HD camera is distributed from the distribution device 10 in the state illustrated in FIG. 6(A). As illustrated in FIG. 6(B), the image from the HD camera is displayed in only a portion of the display area 23 of the display terminal 20, with the remaining display area 23 being blank. FIG. 6(C) illustrates the state immediately after FIG. 6(B), in which the image enlargement ratio is calculated based on the size information (i.e., information indicating that the camera is an HD camera) and the current size of the display area 23, and the image is enlarged and displayed based on this enlargement ratio. As illustrated in FIG. 6(C), the image from the HD camera is displayed at a size optimal for the display area 23 of the display terminal 20. That is, based on the size information acquired from the distribution device 10 and the size of the display area 23, the image from the camera 30 is enlarged and displayed to fit the size of the display area 23. In this way, when the size information transmitted by distribution device 10 is smaller than the size of display area 23, the size information is not changed and the image corresponding to the size information is enlarged to a size that fits within display area 23 and displayed in display area 23. This allows the user to view the image output from camera 30 at an optimal size without necessarily having to set an initial value for size information according to the settings of camera 30 in advance. Specifically, if a value indicating Full HD is set in the settings of camera 30, even if an image from an HD camera is distributed from distribution device 10, the image is automatically displayed on display terminal 20 at an optimal size to fit the size of display area 23, which is determined by a change operation made by the user.

[0102] Fig. 6(D) illustrates an example of a situation where the user enlarges the size of display area 23 in the state illustrated in Fig. 6(C). As illustrated in Fig. 6(D), the image from the HD camera is enlarged and displayed while maintaining an optimal size in accordance with the enlargement of display area 23. Note that, at this time, the HD camera remains connected to distribution device 10, the selected camera information has not been changed, and distribution device 10 has not changed the size information.

[0103] On the other hand, Fig. 6(E) illustrates an example of a situation where the user reduces the size of display area 23 in the state illustrated in Fig. 6(C). As illustrated in Fig. 6(E), the image from the HD camera is displayed reduced while maintaining an optimal size in accordance with the reduction of display area 23. Note that, at this time, the HD camera remains connected to distribution device 10, the selected camera information has not been changed, and distribution device 10 has not changed the size information.

[0104] 7A and 7B are explanatory diagrams illustrating examples of display modes (B to D) when an image from a Full HD camera or an HD camera is delivered from a state (A) in which an image from the camera is not displayed, in the case where a value indicating an HD camera is set as the initial value of the size information. Note that in the example of FIG. 7, the size of the display area 23 is not changed.

[0105] FIG. 7A shows an example of the state of the display area 23 when an image from a camera is not displayed and an initial value indicating an HD camera is set as size information.

[0106] FIG. 7(B) illustrates the state immediately after an image from a Full HD camera is distributed from the distribution device 10 in the state illustrated in FIG. 7(A). As illustrated in FIG. 7(B), only a portion of the image from the Full HD camera is displayed in the display area 23 of the display terminal 20, with the remaining portion being cut off and unrecognizable. FIG. 7(C) illustrates the state immediately after FIG. 7(B), in which the image reduction ratio is calculated based on the size information received from the distribution device 10 (i.e., information indicating the Full HD camera) and the current size of the display area 23, and the image is reduced and displayed based on this reduction ratio. As illustrated in FIG. 7(C), the image from the Full HD camera is displayed at a size optimal for the display area 23 of the display terminal 20. In this way, if the size information transmitted by the distribution device 10 is larger than the size of the display area 23 of the display terminal 20, the image corresponding to the size information is reduced to fit within the display area 23 without changing the size information, and then displayed in the display area 23. This allows the user to view the image output from camera 30 at an optimal size without necessarily having to set in advance an initial value for size information according to the settings of camera 30. Specifically, if a value indicating HD is set in the settings of camera 30, even if an image from a Full HD camera is distributed from distribution device 10, the image is automatically displayed on display terminal 20 at an optimal size to fit the size of display area 23, which is determined by a change operation performed by the user.

[0107] On the other hand, Fig. 7(D) illustrates the state immediately after an image from an HD camera is distributed from distribution device 10 in the state illustrated in Fig. 7(A). As illustrated in Fig. 7(D), the image from the HD camera is displayed at an optimal size for display area 23 of display terminal 20.

[0108] Next, Fig. 8 is an explanatory diagram for explaining examples (B to D) of display modes when the user switches from a state (A) in which an image from a Full HD camera is being displayed to an HD camera or another Full HD camera. Note that in the example of Fig. 8, the size of the display area 23 is not changed.

[0109] 8(A) illustrates an example of the display area 23 when two Full HD cameras and one HD camera (specifically, cameras 30a to 30c in FIG. 1) are connected to distribution device 10 and an image from the Full HD camera is displayed. In the example of FIG. 8(A), the camera 30 related to the selected camera information is a Full HD camera (camera 30a in this example), and the image from camera 30a is displayed at a size optimal for the display area 23 of display terminal 20.

[0110] FIG. 8(B) illustrates the state immediately after the camera 30 associated with the selected camera information is switched to an HD camera (camera 30c in this example) in the state illustrated in FIG. 8(A). As illustrated in FIG. 8(B), the image from the HD camera is displayed in only a portion of the display area 23 of the display terminal 20, with the remaining display area 23 being blank. FIG. 8(C) illustrates the state immediately after FIG. 8(B), in which the image enlargement ratio is calculated based on the size information (i.e., information indicating the HD camera) received from the distribution device 10 and the current size of the display area 23, and the image is enlarged and displayed based on this enlargement ratio. As illustrated in FIG. 8(C), the image from the HD camera is displayed at an optimal size for the display area 23 of the display terminal 20. This allows the user to view the image at an optimal size even when switching from a Full HD camera to an HD camera. In this way, when a value indicating Full HD is set in the settings of camera 30, even if an image from an HD camera is distributed from distribution device 10, the image is automatically displayed at an optimal size on display terminal 20 to fit the size of display area 23 determined by a change operation made by the user.

[0111] Fig. 8(D) illustrates the state immediately after the camera 30 related to the selected camera information is switched to another Full HD camera (camera 30b in this example) in the state illustrated in Fig. 8(A). As illustrated in Fig. 8(D), the size information from camera 30a and the size information from camera 30b are the same, and the image from the Full HD camera is displayed at a size optimal for the display area 23 of the display terminal 20.

[0112] 9A to 9D are explanatory diagrams illustrating examples of display modes when a user switches from a state in which an image from an HD camera (A) is being displayed to a Full HD camera or another HD camera (B to D). Note that in the example of FIG. 9, the size of the display area 23 is not changed.

[0113] 9(A) illustrates an example of the display area 23 when one Full HD camera and two HD cameras (specifically, cameras 30b to 30d in FIG. 1) are connected to distribution device 10 and an image from the HD camera is displayed. In the example of FIG. 9(A), the camera 30 related to the selected camera information is an HD camera (camera 30c in this example), and the image from camera 30c is displayed at a size optimal for the display area 23 of display terminal 20.

[0114] FIG. 9(B) illustrates the state immediately after the camera 30 associated with the selected camera information is switched to a Full HD camera (camera 30b in this example) in the state illustrated in FIG. 9(A). As illustrated in FIG. 9(B), only a portion of the image from the Full HD camera is displayed in the display area 23 of the display terminal 20, with the remaining portion being cut off and unrecognizable. FIG. 9(C) illustrates the state immediately after FIG. 9(B), in which the image reduction ratio is calculated based on the size information received from the distribution device 10 (i.e., a value indicating the Full HD camera) and the current size of the display area 23, and the image is reduced and displayed based on this reduction ratio. As illustrated in FIG. 9(C), the image from the Full HD camera is displayed at an optimal size for the display area 23 of the display terminal 20. This allows the user to view the image at an optimal size even when switching from an HD camera to a Full HD camera. In this way, when a value indicating HD is set in the settings of the camera 30, even if an image from a Full HD camera is distributed from the distribution device 10, the image is automatically displayed at an optimal size on the display terminal 20 to fit the size of the display area 23 determined by changes made by the user, etc.

[0115] Fig. 9(D) illustrates the state immediately after the camera 30 associated with the selected camera information is switched to another HD camera (camera 30d in this example) in the state illustrated in Fig. 9(A). As illustrated in Fig. 9(D), the image from the HD camera is displayed at a size optimal for the display area 23 of the display terminal 20.

[0116] In this embodiment, an example has been described in which the display terminal 20 calculates the enlargement / reduction ratio based on the size information acquired from the distribution device 10 and the size of the display area 23. Also, in this example, the size information is transmitted after the image is transmitted, and the enlargement / reduction ratio is calculated. However, the present invention is not limited to this order, and the size information may be transmitted before the image is transmitted. In other embodiments, the distribution device 10, rather than the display terminal 20, may calculate the enlargement / reduction ratio. In this embodiment, for example, a dedicated application program having a display area 23 for displaying an image transmitted to the display terminal 20 is installed and executed by the processor of the display terminal 20.

[0117] 10 to 12, another embodiment will be described in which the distribution device 10 calculates the enlargement / reduction ratio and the display terminal 20 displays an image based on the enlargement / reduction ratio calculated by the distribution device 10. Note that a description of the same configuration as that described with reference to FIGS. 1 to 9 will be omitted.

[0118] 10 is an explanatory diagram showing an example of the overall configuration of image distribution system 1 in another embodiment in which the enlargement / reduction ratio is updated by distribution device 10. In the embodiment shown in FIG. 10, distribution device 10 includes image acquisition unit 11, image storage unit 12, size information acquisition unit 13, size information storage unit 14, display area information receiving unit 16, enlargement / reduction ratio calculation unit 17, and image enlargement / reduction ratio transmission unit 18. Each of the above units included in distribution device 10 is realized by distribution device 10 including hardware such as a processor, storage device (including memory), and communication module, and by the processor executing a predetermined program stored in the storage device.

[0119] The display area information receiving unit 16 receives display area information from the display terminal 20 (specifically, the display area information transmitting unit 26). The display area information is information indicating the size of the display area 23 of the display terminal 20, and is information transmitted from the display area information transmitting unit 26 to the display area information receiving unit 16 as the size of the display area 23 is changed in response to a user operation.

[0120] The enlargement / reduction ratio calculation unit 17 calculates the enlargement / reduction ratio of the image based on the size information read from the size information storage unit 14 and the size of the display area 23 indicated by the display area information.

[0121] In response to an image distribution request from the display terminal 20, the image / enlargement / reduction ratio transmission unit 18 transmits to the display terminal 20 the image from the camera 30 acquired by the image acquisition unit 11 and the enlargement / reduction ratio calculated by the enlargement / reduction ratio calculation unit 17. In the embodiment illustrated in FIG. 10 , the enlargement / reduction ratio is transmitted together with the image. However, the present invention is not limited to this order, and the enlargement / reduction ratio may be transmitted before or after the image is transmitted. When multiple cameras 30 are connected to the distribution device 10, the image distribution request from the display terminal 20 includes selected camera information indicating information about the camera 30 selected by the user of the display terminal 20. The image / enlargement / reduction ratio transmission unit 18 transmits to the display terminal 20 the image acquired from the camera 30 indicated by the selected camera information and the enlargement / reduction ratio of the image. In addition, the image enlargement / reduction ratio transmission unit 18 may transmit to the display terminal 20, in response to a request from the user of the display terminal 20, an image read from the image storage unit 12 and the enlargement / reduction ratio of the image calculated based on the size information of the image read from the size information storage unit 14 and the size of the display area 23 indicated by the display area information.

[0122] In addition, in the embodiment illustrated in Figure 10, the display terminal 20 includes a display area information transmitting unit 26, an image enlargement / reduction ratio receiving unit 27, a display area 23, a selected camera information transmitting unit 24, and an input unit 25.

[0123] The display area information transmitting unit 26 transmits the display area information to the distribution device 10 as the size of the display area 23 is changed in response to a user operation.

[0124] The image / enlargement / reduction ratio receiving unit 27 receives the image and the enlargement / reduction ratio transmitted from the distribution device 10. Specifically, the image / enlargement / reduction ratio receiving unit 27 receives the enlargement / reduction ratio from the distribution device 10 along with the image transmitted in streaming format from the distribution device 10.

[0125] 11 is a flowchart showing an example of a distribution device process executed by the distribution device 10 in another embodiment in which the enlargement / reduction ratio is updated by the distribution device 10. As illustrated in step SH201 of FIG. 11, the distribution device 10 initializes the size information, the display area information, the enlargement / reduction ratio, and the selected camera information.

[0126] After the process of step SH201, the distribution device 10 performs the processes of steps SH102 to SH105 similar to those in Fig. 2. These processes are the same as those described above, and therefore the description thereof will be omitted.

[0127] When the processing of step SH105 is executed, the distribution device 10 (specifically, the display area information receiving unit 16) determines whether or not display area information has been received from the display terminal 20 (step SH202). If the determination in step SH202 is YES, the display area information receiving unit 16 updates the content of the display area information stored in the distribution device 10 to the content indicated by the received display area information (step SH203).

[0128] If the answer is NO in step SH202, or if the processing of step SH203 has been executed, the distribution device 10 executes a distribution device calculation and transmission process for calculating the enlargement / reduction ratio and transmitting the calculated ratio to the display terminal 20 (step SH204). The distribution device calculation and transmission process will be described with reference to FIG.

[0129] Fig. 12 is a detailed flowchart of the distribution device calculation and transmission process in step SH204 of Fig. 11. The distribution device 10 determines whether the image acquired in step SH105 is an I frame (step SH301).

[0130] If the answer is NO in step SH301, the distribution device 10 (specifically, the enlargement / reduction ratio calculation unit 17) calculates and updates the enlargement / reduction ratio of the image received in step SH105 based on the previously acquired size information and the size of the display area 23 indicated by the display area information (step SH307).

[0131] On the other hand, if the answer is YES in step SH301, the distribution device 10 (specifically, the size information acquisition unit 13) acquires size information based on the I frame and stores it in the size information storage unit 14 (step SH302).

[0132] When the processing of step SH302 is executed, the distribution device 10 (specifically, the enlargement / reduction ratio calculation unit 17) determines whether the size of the display area 23 indicated by the display area information is smaller than the size information calculated in step SH302 (step SH303).

[0133] If the answer is YES in step SH303, that is, if the size of the display area 23 is smaller than the size information, the distribution device 10 (specifically, the enlargement / reduction ratio calculation unit 17) calculates the reduction ratio of the image received in step SH105 based on the size information and the size of the display area 23 indicated by the display area information (i.e., updates the enlargement / reduction ratio: step SH304).

[0134] On the other hand, if the result of step SH303 is NO, the distribution device 10 (specifically, the enlargement / reduction ratio calculation unit 17) determines whether the size of the display area 23 indicated by the display area information is larger than the size information calculated in step SH302 (step SH305). If the result of step SH305 is YES, that is, if the display area 23 is larger than the size information, the enlargement / reduction ratio calculation unit 17 calculates the enlargement ratio of the image received in step SH105 based on the size information and the size of the display area 23 indicated by the display area information (i.e., updates the enlargement / reduction ratio: step SH306).

[0135] If the processing of step SH304 has been executed, if NO in step SH305, if the processing of step SH306 has been executed, or if the processing of step SH307 has been executed, the distribution device 10 (specifically, the image enlargement / reduction ratio transmission unit 18) associates the image received in step SH105 with the enlargement / reduction ratio (specifically, the enlargement / reduction ratio updated in the processing of step SH304, step SH306, or step SH307) and transmits them to the display terminal 20 (step SH308). With this, the distribution device 10 ends the distribution device calculation / transmission process and proceeds to step SH202.

[0136] In addition, in step SH308, the distribution device 10 (specifically, the image enlargement / reduction ratio transmission unit 18) may associate the image received in step SH105 with the enlargement / reduction ratio and size information used to calculate the enlargement / reduction ratio and transmit them to the display terminal 20.

[0137] In another embodiment in which the enlargement / reduction ratio is updated by the distribution device 10, the display terminal 20 does not perform the process of calculating and updating the enlargement / reduction ratio shown in FIG. 3 described above. Specifically, for example, when the size of the display area 23 is changed by a user, the display terminal 20 (specifically, the display area information transmitting unit 26) transmits display area information regarding the size of the display area 23 to the distribution device 10 (specifically, the display area information receiving unit 16). Furthermore, the display terminal 20 (specifically, the image / enlargement / reduction ratio receiving unit 27) displays the image in the display area 23 based on the image and the enlargement / reduction ratio transmitted by the distribution device 10 in step SH308 described above. This allows the user to view the image output from the camera 30 at an optimal size without necessarily having to set an initial value for the size information according to the settings of the camera 30 in advance. Specifically, if a value indicating Full HD is set in the settings of the camera 30, even if an image from an HD camera is distributed from the distribution device 10, the image will automatically be displayed at the optimal size on the display terminal 20 to fit the size of the display area 23, which is determined by changes made by the user, etc.

[0138] [Effects of this embodiment] An image distribution system 1 according to one aspect of the present invention is an image distribution system including a distribution device 10 that acquires an image output from an imaging device (e.g., a camera 30) and distributes it to a display terminal 20. The distribution device 10 acquires size information regarding the size of the image based on the image (e.g., an I frame) acquired from the imaging device, and transmits the image (e.g., an I frame, a P frame, and a B frame) and the size information to the display terminal 20. If the size information acquired by the distribution device 10 is larger than the current size of the display area 23 of the display terminal 20, the scaling display processing unit 22 of the display terminal 20 reduces the image corresponding to the size information to fit within the display area 23 without changing the size information, and displays it in the display area 23. If the size information acquired by the distribution device 10 is smaller than the current size of the display area 23, the scaling display processing unit 22 of the display terminal 20 enlarges the image corresponding to the size information to a range that fits within the display area 23 without changing the size information, and displays it in the display area 23.

[0139] As described above, the distribution device 10 transmits size information to the display terminal 20, and the display terminal 20 can use the size information to display an image at an optimal size for the display area.

[0140] An image distribution system 1 according to an aspect of the present invention is an image distribution system including a distribution device 10 that acquires an image output from an imaging device (e.g., a camera 30) and distributes it to a display terminal 20. The distribution device 10 acquires size information regarding the size of the image based on the image (e.g., an I frame) acquired from the imaging device, and transmits the image (e.g., an I frame, a P frame, and a B frame) and a magnification / reduction ratio to the display terminal 20. In addition, the distribution device 10 may also transmit the size information to the display terminal 20. If the size information acquired by the distribution device 10 is larger than the current size of the display area 23 of the display terminal 20, the reduction ratio is calculated in step SH204 of FIG. 11 and transmitted to the display terminal 20 together with the image from the camera. As a result, the image corresponding to the size information is reduced to fit within the display area 23 without changing the size information, and is displayed in the display area 23. If the size information acquired by the distribution device 10 is smaller than the current size of the display area 23, the magnification ratio is calculated in step SH204 of FIG. 11 and transmitted to the display terminal 20 together with the image from the camera. As a result, the image corresponding to the size information is enlarged within the range that fits within the display area 23 without changing the size information, and is displayed in the display area 23.

[0141] As described above, the distribution device 10 transmits the enlargement / reduction ratio calculated using the size information to the display terminal 20, thereby enabling the distribution device 10 and the display terminal 20 to display an image at an optimal size for the display area.

[0142] In addition, in an image distribution system 1 according to one embodiment of the present invention, when the camera 30 is a camera that captures video, the distribution device 10 updates the size information at the time interval (a fixed time interval or a random time interval) at which I frames are acquired, and the image distribution system 1 displays the video in the display area 23 based on the updated size information.

[0143] As a result of the above, the size information is updated, so that, for example, if the settings of the camera 30 are changed, the image distribution system 1 can display the video output from the camera 30 after the settings have been changed at an optimal size in the display area 23 in accordance with the update.

[0144] In addition, in an image distribution system 1 according to one embodiment of the present invention, when the camera 30 periodically acquires still images at a preset time interval (for example, every second), the distribution device 10 updates the size information at the time interval (for example, every second) at which the image is acquired, and the image distribution system 1 displays the image in the display area 23 based on the updated size information.

[0145] As a result of the above, the size information is updated, so that, for example, when the settings of the camera 30 are changed, the image distribution system 1 can display the image output from the camera 30 after the settings have been changed at the optimal size for the display area 23 in accordance with the above update.

[0146] The camera 30 related to the selected camera information may be automatically switched by the distribution device 10 every time a predetermined time (e.g., 10 seconds) has elapsed. For example, if the camera settings are different each time the camera is automatically switched, the distribution device 10 updates the size information at the predetermined time interval, and the image distribution system 1 displays the image in the display area 23 based on the updated size information.

[0147] As a result of the above, the size information is updated, so that, for example, when the settings of the camera 30 are changed, the image distribution system 1 can display the image output from the camera 30 after the settings have been changed at the optimal size for the display area 23 in accordance with the above update.

[0148] [Variations] The input unit 25 of the display terminal 20 may be usable for a user to specify a date and time. For example, in response to a specifying operation, the display terminal 20 transmits date and time information indicating the date and time to the distribution device 10. Upon receiving the date and time information, the distribution device 10 reads an image for the date and time indicated by the date and time information from the image storage unit 12 and acquires size information for the image based on the image. The distribution device 10 then transmits the image and the size information to the display terminal 20. When the size information transmitted by the distribution device 10 is larger than the current size of the display area 23 of the display terminal 20, the image distribution system 1 reduces the image corresponding to the size information to fit within the display area 23 without changing the size information, and displays the image in the display area 23. When the size information transmitted by the distribution device 10 is smaller than the current size of the display area 23, the image corresponding to the size information is enlarged within the display area 23 without changing the size information, and then displays the image in the display area 23.

[0149] The cameras 30 may include cameras equipped with motion detection sensors. The distribution device 10 may then set one of the cameras 30 that has detected motion using its motion detection sensor as the camera related to the selected camera information. In such a case, if multiple cameras 30 simultaneously detect motion, the camera with the highest priority may be set as the camera 30 related to the selected camera information.

[0150] In this embodiment, a configuration is adopted in which an image output from one selected camera 30 is displayed in the display area 23 of the display terminal 20. In other embodiments, a configuration may be adopted in which images output from at least two or more cameras 30 connected to the distribution device 10 can be simultaneously displayed in the display area 23 of the display terminal 20. For example, if camera 30a and camera 30b are connected to the distribution device 10, a first image output from camera 30a is displayed in a predetermined area (e.g., the left area) in the display area 23 of the display terminal 20, and a second image output from camera 30b is displayed in another area (e.g., the right area) in the display area 23 of the display terminal 20.

[0151] In addition, in the case of a configuration in which images output from multiple cameras 30 can be displayed simultaneously in the display area 23 of the display terminal 20 as described above, the image distribution system 1 does not need to have a configuration for selecting a camera 30 (i.e., a configuration related to selected camera information), or at least two or more cameras 30 may be set as cameras 30 related to the selected camera information.

[0152] In the present embodiment, the distribution device 10 transmits size information to the display terminal 20 when the display terminal 20 requests it to transmit size information if the image acquired from the camera 30 is an I-frame, which is a key frame for inter-frame prediction. However, the transmission of the size information is not limited to this, and the size information may be transmitted to the display terminal 20 at predetermined time intervals. For example, the method may be applied when the image acquired from the camera 30 is compressed as a still image (e.g., Motion JPEG) and a video is constructed based on a series of still images.

[0153] The configuration and operation of the image distribution system 1 described in the above embodiment are merely examples, and it goes without saying that the present invention can be realized with other configurations and operation modes. Furthermore, the processing order, setting values, etc. in the above flowcharts are merely examples, and it goes without saying that the present invention can be realized with other orders and values ​​without departing from the scope of the present invention. The explanatory diagrams, etc. illustrated in the above embodiment are also merely examples, and other modes are also possible.

[0154] The above-mentioned numerical values ​​are merely examples, and the present invention is not limited to the above-mentioned embodiment, but various modifications and applications are possible. Furthermore, the above-mentioned embodiment and modifications can be mutually applied, and the present invention can be realized in various combinations. [Explanation of symbols]

[0155] 1. Image distribution system 10. Distribution Device 11 Image acquisition unit 12 Image storage unit 13 Size information acquisition section 14 Size information storage section 15 Image and size information transmission section 16 Display area information receiving unit 17 Enlargement / reduction ratio calculation section 18 Image enlargement / reduction ratio transmission section 20 Display terminal 21 Image and size information receiver 22 Zooming display processing section 23 Display area 24 Selected camera information transmitter 25 Input section 26 Display area information transmission unit 27 Image enlargement / reduction ratio receiver 30 Camera

Claims

1. An image distribution system including a distribution device that acquires an image output from an imaging device and distributes it to a display terminal, The distribution device acquiring size information relating to the size of the image based on the image acquired from the imaging device; transmitting the image and the size information to the display terminal; The image distribution system includes: If the size information transmitted by the distribution device is larger than the size of a display area of ​​the display terminal, the image corresponding to the size information is reduced so as to fit within the display area without changing the size information, and is displayed in the display area; An image distribution system in which, if the size information transmitted by the distribution device is smaller than the size of the display area, the image corresponding to the size information is enlarged to the extent that it fits within the display area without changing the size information and displayed in the display area.

2. The distribution device updates the size information at predetermined time intervals, The image delivery system according to claim 1 , wherein the image delivery system displays the image in the display area based on the updated size information.

3. the distribution device acquires a video as the image, and updates the size information each time a predetermined frame of the video is acquired; The image delivery system according to claim 1 , wherein the image delivery system displays the moving image in the display area based on the updated size information.

4. the imaging device includes at least a first imaging device and a second imaging device; The distribution device acquiring first size information relating to a size of a first image acquired from the first imaging device; 4. The image distribution system according to claim 1, further comprising: acquiring second size information relating to a size of the second image based on the second image acquired from the second imaging device.

5. a selection unit for selecting one of the first and second imaging devices; The distribution device When the first imaging device is selected by the selection means, the first image and the first size information are transmitted to the display terminal; 5. The image distribution system according to claim 4, wherein when the second imaging device is selected by the selection means, the second image and the second size information are transmitted to the display terminal.

6. the selection means selects one of the first imaging device and the second imaging device in response to a selection operation by a user; When the selection operation for selecting the second imaging device is performed while the first image is being displayed in the display area of ​​a predetermined size, the image delivery system: If the second size information is larger than the display area of ​​the predetermined size, the second image is reduced so as to fit within the display area without changing the second size information, and is displayed in the display area of ​​the predetermined size; 6. The image distribution system of claim 5, wherein, when the second size information is smaller than the display area of ​​the specified size, the second image is enlarged to the extent that it fits within the display area without changing the second size information and displayed in the display area of ​​the specified size.

7. the display terminal includes a display area resizing means for changing the size of the display area in response to a resizing operation by a user; When the display area is enlarged by the display area resizing means, the image is enlarged in accordance with the enlargement of the display area and displayed in the display area; 7. The image delivery system according to claim 1, wherein when the display area is reduced by the display area resizing means, the image is reduced in size in accordance with the reduction of the display area and displayed in the display area.

8. A distribution device that acquires an image output from an imaging device and distributes it to a display terminal, a size information acquisition means for acquiring size information relating to the size of the image based on the image acquired from the imaging device; a transmitting means for transmitting the image and the size information to the display terminal; If the size information is larger than the size of the display area of ​​the display terminal, the size information is not changed, and the image corresponding to the size information is reduced so as to fit within the display area and displayed in the display area; A distribution device in which, if the size information is smaller than the size of the display area, the size information is not changed and the image corresponding to the size information is enlarged to the extent that it fits within the display area and displayed in the display area.

9. A distribution device that acquires an image output from an imaging device and distributes it to a display terminal, a size information acquisition means for acquiring size information relating to the size of the image based on the image acquired from the imaging device; a display area information receiving means for receiving display area information relating to the size of the display area of ​​the display terminal from the display terminal; a reduction ratio calculation means for calculating, when the size information is larger than the size of the display area, a reduction ratio for reducing the image so that it fits within the display area, based on the size information and the display area information; an enlargement ratio calculation means for calculating, when the size information is smaller than the size of the display area, an enlargement ratio for enlarging the image within a range that fits within the display area, based on the size information and the display area information; a transmitting means for transmitting the image and either the reduction ratio or the enlargement ratio to the display terminal.

10. An image distribution method for acquiring an image output from an imaging device and distributing it to a display terminal, comprising: an image acquisition unit acquiring an image output from the imaging device; a size information acquisition unit acquiring size information relating to the size of the image based on the image acquired by the image acquisition unit; a transmitting unit transmitting the image and the size information to the display terminal; a step of reducing the image corresponding to the size information so that it fits within the display area without changing the size information when the size information transmitted by the transmission unit is larger than the size of the display area of ​​the display terminal, and displaying the image in the display area; If the size information transmitted by the transmitting unit is smaller than the size of the display area, the image corresponding to the size information is enlarged to the extent that it fits within the display area without changing the size information, and then displayed in the display area.

11. A program executed on a computer of a distribution device that acquires an image output from an imaging device and distributes the image to a display terminal, The computer a size information acquisition means for acquiring size information relating to the size of the image based on the image acquired from the imaging device; a transmitting means for transmitting the image and the size information to the display terminal; If the size information is larger than the size of the display area of ​​the display terminal, the size information is not changed, and the image corresponding to the size information is reduced so as to fit within the display area and displayed in the display area; When the size information is smaller than the size of the display area, the size information is not changed and the image corresponding to the size information is enlarged to the extent that it fits within the display area and displayed in the display area.

Images