JP3956010B2 - Video transmission system and video transmission control method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention performs operations such as turning, zooming, and focusing on a camera that captures a monitored part, and compressing and encoding a video signal from the camera, and transmitting the video signal to an operation terminal that operates the camera for display. The present invention relates to a system and a video transmission control method.
[0002]
[Prior art]
As monitoring and observation systems, for example, systems such as river flooding monitoring, road traffic congestion and accident monitoring, crowd accident monitoring, and earthquake disaster monitoring are known. In these systems, a monitored portion is imaged by a single or a plurality of cameras, and the captured video signal is compressed and encoded, for example, and transmitted to a monitoring unit, etc., and is decoded and displayed on the monitoring unit. In general, an image of a monitored portion is displayed on the screen, and a camera is remotely operated from the monitoring unit or the like. In that case, the camera is remotely controlled to include means for performing turn control for sequentially monitoring over a wide range, zoom-up control for making a detailed reproduced image, and the like. When transmitting a video signal from a camera, compression encoding is generally performed, and standardized MPEG (Moving Picture Experts Group) -2 can be applied as a means for compression encoding.
[0003]
The MPEG-2 has three types of picture structures of an I picture (Intra-coded Picture), a P picture (Predictive-coded Picture), and a B picture (Bi-directive Predictive-coded Picture), and a fixed bit rate. (CBR: Constant Bit Rate) encoding, variable bit rate (VBR) encoding, and intra slice encoding in which intra blocks are distributed in a slice layer are defined.
[0004]
In CBR encoding and VBR encoding, it is necessary to prepare a reception buffer area corresponding to an I picture having the largest amount of encoded information. Also, it takes about 3 frames to generate a B picture by bidirectional prediction. Therefore, the delay time required until the state of the monitored portion imaged by the camera is displayed on the display unit of the operation terminal becomes a factor. In contrast, intra-slice coding in which an intra picture is inserted into a frame as a slice reduces the picture size and reduces fluctuations, so that the reception buffer area can be reduced and the delay time can be reduced. Can also be reduced.
[0005]
[Problems to be solved by the invention]
As the compression coding, the above-described intra slice coding does not perform bi-directional predictive coding for obtaining a B picture, so that the delay time can be reduced compared to CBR coding and VBR coding. When the same bit rate is used, there is a problem that the reproduction image quality is relatively inferior. On the operation terminal side, it is displayed as a moving image, but a still image may be extracted and stored. In this case, intra slice coding has a problem that it is difficult to extract as a still image because there is no isolated I picture.
[0006]
In addition, when the camera is operated from the operation terminal, as described above, when turning control or zooming control is performed, the difference between frames becomes large. Therefore, a large amount of information is generated in the above-described CBR coding and VBR coding. Thus, the delay time is further increased. That is, there is a problem that it takes a long time to display the image of the monitored portion after the camera control.
The present invention solves the above-mentioned conventional problems. By switching between a high quality mode and a low delay mode based on camera operation, the monitored portion can be quickly covered during high-quality playback display and camera operation. An object is to quickly display different imaging areas of a monitoring portion.
[0007]
[Means for Solving the Problems]
The video transmission system of the present invention will be described with reference to FIG. 1. A video transmission apparatus 2 that compresses and transmits a video signal from the camera 1 and a compressed and encoded video signal received from the video transmission apparatus 2 are transmitted. A video transmission system including an operation terminal 3 for decoding and displaying on the video display unit 11 and controlling the camera 1, wherein the video transmission device 2 receives a video signal from the camera 1. A high quality mode encoding unit 8 that inputs and compresses and encodes using an intra frame and a video signal of the camera 1 are input, and the movement direction of the screen is controlled by controlling the imaging direction and imaging range of the camera 1. A low delay mode encoding unit 7 that compresses and encodes a large number of intra blocks; A mode selection unit 6 that switches between the low delay mode encoding unit 7 and the high quality encoding unit 8, and the operation terminal 3 A control signal for controlling the imaging direction and imaging range of the camera 1 is received, and the mode selection unit 6 And a control signal processing unit 9 for selecting the low delay mode encoding unit 7.
[0008]
The control signal processing unit 9 of the video transmission apparatus 2 receives and identifies a control signal for controlling the camera 1 from the camera operation unit 13 of the operation terminal 3, controls the mode selection unit 6, and controls a high quality mode encoding unit. 8 is switched to the low-delay mode encoding unit 7, and after the series of control of the camera 1 is completed, the low-delay mode encoding unit 7 is switched to the high-quality mode encoding unit 8. The second low-delay mode encoding unit 7 can be configured to control the intra-block generation distribution according to the moving direction of the screen by controlling the imaging direction such as up / down / left / right of the camera and the imaging range such as zooming. .
[0009]
The video transmission control method of the present invention controls the camera 1 from the operation terminal 3, compresses and encodes the video signal from the camera 1 in the video transmission apparatus 2, and transmits the video signal to the operation terminal 3 for display. In the signal transmission control method, in the process of controlling the imaging direction and imaging range of the camera 1 from the operation terminal 3, the video signal from the camera 1 is compression-encoded in the low delay mode and sent to the operation terminal 3. Then, a process including compression encoding in the high quality mode and sending to the operation terminal 3 is included.
[0010]
In addition, in the process of controlling the imaging direction such as up and down, left and right of the camera 1 and the imaging range such as zooming, the process of performing compression coding in the low delay mode and controlling the distribution of intra blocks according to the direction of the screen motion. Can be included.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram of an embodiment of the present invention. 1 is a camera, 2 is a video transmission device, 3 is an operation terminal, 4 is a control mechanism unit, 5 is an image encoding unit, 6 is a mode selection unit, 7 Is a low delay mode encoding unit, 8 is a high quality mode encoding unit, 9 is a control signal processing unit, 10 is an image decoding unit, 11 is a video display unit, 12 is a still image storage unit, and 13 is a camera operation unit. Show.
[0012]
In the camera 1, the control mechanism unit 4 performs control of the imaging direction in the vertical and horizontal directions for monitoring a wide range of monitored parts, the control of the imaging range by zooming in and zooming out, and the control of focusing on a distant view or a close view. The control mechanism unit 4 includes a motor for rotating the swivel base, a motor for zooming the lens of the camera 1, or a motor for focusing on a distant view or a close view. Various configurations can be applied.
[0013]
The video transmission device 2 also inputs the video signal (analog video signal) from the camera 1 to the low delay mode encoding unit 7 or the high quality mode encoding unit 8 via the mode selection unit 6 and performs compression encoding. The received video signal (digital video signal) is sent to the operation terminal 3. The video transmission apparatus 2 includes a control signal processing unit 9, controls the mode selection unit 6 according to the control signal from the operation terminal 3, and sends a camera control signal to the control mechanism unit 4 of the camera 1.
[0014]
The low delay mode encoding unit 7 of the image encoding unit 5 compresses and encodes the video signal from the camera 1 by reducing the delay time by applying the above-described intra-slice encoding in MPEG2. In addition, the high quality mode encoding unit 8 applies CBR encoding or VBR encoding, and performs encoding that can improve the reproduction image quality even if the delay time is slightly increased.
[0015]
In various monitoring systems, observation systems, and the like, the camera 1 and the operation terminal 3 are generally arranged at a distance from each other, and the video transmission device 2 is generally arranged on the camera 1 side. The video transmission apparatus 2 and the operation terminal 3 are connected by a digital transmission path, and a digital video signal compressed and encoded in the video transmission apparatus 2 is sent to the operation terminal 3. Further, the operation terminal 3 shows a case where an image decoding unit 10, a video display unit 11, a still image storage unit 12, and a camera operation unit 13 are provided, and control means such as a processor for controlling each unit (not shown) is provided. I have. Then, the image decoding unit 10 decodes the received digital video signal, displays the captured image of the camera 1 on the video display unit 11, and extracts the still image extracted from the decoded video signal at a fixed time interval or the like. Accumulate in the accumulation unit 12. This still image is reproduced and displayed when analyzing the detailed state of the monitored portion.
[0016]
The camera operation unit 13 of the operation terminal 3 is configured by a switch, a button, or the like, or an operation unit using a part of the area on the display screen of the video display unit 11, and a turning control signal for the camera 1 according to the operation. Send zooming control signals and so on. Such a control signal is generally transmitted via a signal line between the operation terminal 3 and the video transmission apparatus 2, but is configured to transmit using a transmission path for transmitting a digital video signal. It is also possible.
[0017]
Further, the control signal processing unit 9 of the video transmission device 2 performs high quality mode encoding on the mode selection unit 6 when the control signal for turning control and zooming control of the camera 1 from the operation terminal 3 is not received. A mode switching control signal for selecting the unit 8 is added. That is, when the camera 1 is not operated, compression encoding is performed in the high quality mode in which the reproduction image quality is good in the high quality mode. When a control signal is received from the operation terminal 13, a mode switching control signal for selecting the low delay mode encoding unit 7 is added to the mode selection unit 6.
[0018]
Therefore, when the camera 1 is not operated, the video signal from the camera 1 is compression-encoded by the above-mentioned CBR encoding or VBR encoding which becomes a high quality mode, and the camera 1 is controlled to turn or zoom. When performing, compression encoding is performed by intra-slice encoding in a low delay mode. As a result, when the camera 1 is not controlled to turn or zoom, a high-quality playback screen that captures a certain monitored portion can be obtained, and when the camera 1 is controlled to turn or zoom. Can reproduce and display an imaging screen in which the imaging range of the monitored portion has changed with a low delay time, and can quickly monitor the state of the monitored portion during camera operation.
[0019]
FIG. 2 is an explanatory diagram when switching from the high quality mode to the low delay mode. In this state, frames V1, V2, V3,... Are sequentially input as video input frames input to the image encoding unit. On the other hand, mode switching timing, high quality mode delay time, high quality mode encoded data, low delay mode delay time, low delay mode encoded data, reception side switching time, and display video data are shown. .
[0020]
Further, the time Ts required for switching at the transmission side, that is, the video transmission apparatus 2, the delay time Th in the high quality mode encoding, the delay time Tl in the low delay mode encoding, the high quality mode encoding and the low When the delay time difference Td = Th−Tl in the delay mode encoding and the time Tr required for switching at the receiving side, that is, the operation terminal 3, the delay time Th in the high quality mode is By including the process of encoding with reference to the frame, the delay time is at least 3 frames. For example, the high quality mode encoded data corresponding to V1 of the video input frame is indicated by V1 after the delay time Th.
[0021]
On the other hand, in the low delay mode encoding, the delay time of Tl <Th is obtained by including a process of encoding without referring to the preceding and succeeding frames. For example, the low delay mode encoded data corresponding to V4 of the video input frame is indicated by V4 after the delay time Tl. On the reception side, switching from decoding of high quality mode encoded data to decoding of low delay mode encoded data is performed, and the time Tr required for this switching can be expressed as Tr = Ts−Td. Accordingly, when the time Ts required for switching is equal to or smaller than the delay time difference Td, the time Tr required for switching on the receiving side is substantially zero. That is, when switching from high quality mode coding to low delay mode coding, the process of switching the decoding reproduction display screen on the receiving side is performed smoothly.
[0022]
On the other hand, the switching from the low delay mode to the high quality mode will be described with reference to FIG. 3 corresponding to FIG. 2. In the low delay mode encoding, the low delay corresponding to V 1 of the video input frame is used. The mode encoded data is output as shown as V1 after the delay time Tl. When switching from low delay mode encoding to high quality mode encoding, a frame corresponding to, for example, V4 of the video input frame is output as high quality mode encoded data after a delay time Th.
[0023]
Accordingly, the display video data decoded and reproduced in the image decoding unit is decoded and reproduced from the low-delay mode encoded data, and then decoded and reproduced from the high-quality mode encoded data. In order to decode and reproduce and display the high quality mode encoded data after the V2 frame in which the encoded data is decoded, Tr switching time is required. During this period, for example, the V2 frame is displayed as a still image. Measures such as continuing are necessary. Therefore, the time interval of occurrence of the factor for switching from the low delay mode coding to the high quality mode coding needs to be at least larger than Tr in order to perform moving image display.
[0024]
FIG. 4 is an explanatory diagram of the control signal. A control signal from the camera operation unit 13 of the operation terminal 3 is transmitted to the mode selection unit 6 and the control mechanism unit 4 via the control signal processing unit 9 of the video transmission apparatus 2. Indicates the sequence to send. By performing control input of turning and zooming of the camera 1 by the camera operation unit 13, first, a switching instruction signal for switching to low delay mode encoding is transferred to the control signal processing unit 9 of the video transmission device 2. The control signal processing unit 9 adds a mode switching control signal for switching from the high quality mode coding to the low delay mode coding to the mode selection unit 6 by the switching instruction signal. Then, a camera control signal according to the control input of the camera 1 is sent from the camera operation unit 13.
[0025]
The control signal processing unit 9 sends a camera control signal to the control mechanism unit 4. Thereby, the control mechanism unit 4 performs turning and zooming of the camera 1. When the control operation of the camera 1 is completed, a switching instruction signal for high-quality mode encoding is transmitted from the camera operation unit 13. The control signal processing unit 9 of the video transmission apparatus 2 adds a mode switching control signal for switching from the low delay mode coding to the high quality mode coding to the mode selection unit 6.
[0026]
FIG. 5 is an explanatory diagram of the camera operation unit, and shows the function of the camera operation unit using the screen of the video display unit 11 (see FIG. 1). FIG. 5A shows the display area of the monitored portion shown as the moving image display unit. If the cursor is pointed to the top, bottom, left, right, or center and clicked, for example, if it is a right region, it is an input for turning the camera 1 to the right, and if it is a central region, it is an input for zooming. be able to. FIG. 4B shows a case in which the up / down / left / right buttons and the zoom button are displayed beside the moving image display portion, and a turn or zooming is input by clicking with a cursor instruction. Thus, the control means for forming various input operation areas in the monitor screen and performing the input operation by a cursor instruction or the like can be easily realized by a known computer technique.
[0027]
FIG. 6 is a schematic flowchart of processing of the camera operation unit. When the mouse is moved to the area of the moving image display unit in FIG. 5A or the operation button area in FIG. (A5), the transition to the low delay mode is started (A4). That is, as shown in FIG. 4, a switching instruction signal for switching to low delay mode encoding is sent from the camera operation unit to the control signal processing unit. And the camera control signal according to the click content is sent out. For example, when the left button of the operation button is clicked, a left turn control signal is transmitted.
[0028]
If the cursor is moved to the moving image display area in FIG. 5A or the operation button area in FIG. 5B but not clicked (A1), a timer for n seconds is started (A2). After n seconds, the cursor position is determined (A3). If the cursor moves out of the area, the process proceeds to the original step. If the cursor is in the area, the camera control input is expected and the low delay mode is entered. Transition start (A4), that is, a switching instruction signal for switching to low delay mode encoding is sent from the camera operation unit to the control signal processing unit.
[0029]
In the operation terminal 3, the state of the transition to the high quality mode and the low delay mode and the state of the low delay mode can be displayed by changing the shape of the mouse pointer. For example, various shapes such as an arrow, a cross, and an hourglass indicating that processing is in progress are known as the shape of the mouse pointer, but the shape that displays the high quality mode and the transition to the low delay mode are displayed. A shape and a shape for displaying the low delay mode are prepared, and the mouse pointer shape can be switched by mode identification.
[0030]
For example, as shown in the explanatory diagram of the mouse pointer shape control in FIG. 7, when the high quality mode video data is received from the video transmission device 2 (see FIG. 1), the mouse pointer shape is set to the high quality mode display shape. When the above switching instruction signal is sent in accordance with the operation input of the camera control, the display shape is set during the transition to the low delay mode, and when the low delay mode video data is received from the video transmission device 2 by the mode switching, The display shape can be changed.
[0031]
As a result, as shown in FIGS. 5A and 5B, depending on the cursor position on the monitor screen and the shape of the mouse pointer in the camera operation input by clicking, a transition is currently made between the high quality mode and the low delay mode. It is possible to distinguish between medium and low delay modes. Therefore, camera operation input can be performed only in the high quality mode. In addition, when the low-delay mode transition is in progress, it is possible to disable the camera operation button click acceptance. Such a mouse pointer shape, click acceptance invalidation processing, and the like can be easily realized.
[0032]
When the video transmission apparatus 2 and the operation terminal 3 are connected by a local area network (LAN), the transmission format is a packet with a header added to a predetermined length of data. For example, as shown in FIG. A mode identification header is added as a header of a predetermined length of MPEG data (the above-mentioned high quality mode encoded data or low delay mode encoded data), and either the high quality mode or the low delay mode is added to the mode identification header. By adding the information for identifying the mode identification header, the mode identification header is extracted in the operation terminal 3, for example, in the image decoding unit 10 or in the reception processing unit in the preceding stage (not shown). Then, it is determined whether the high quality mode video data is being received or the low delay mode video data is being received, and the mouse pointer shape described in FIG. 7 is changed. It is possible.
[0033]
FIG. 9 is an explanatory diagram of an MPEG-2 video stream, and mode information can be added to the extension & user area together with a sequence header and sequence extension. As a result, when transmitting as a video stream, the image decoding unit 10 or the preceding stage omits illustration of which data is encoded by the above-described high quality mode encoding or low delay mode encoding. The reception processing unit can identify and change the shape of the mouse pointer.
[0034]
FIG. 10 is a schematic explanatory diagram of the video stream in the high quality mode and the low delay mode, showing only the main points of the MPEG-2 video stream shown in FIG. 9, (A) is the high quality mode, and (B) is the low delay. Indicates the mode. The group of picture header (GOP header) in the high quality mode in FIG. 10A is omitted in the low delay mode in FIG. Therefore, even when the MPEG-2 video stream is transmitted between the video transmission apparatus 2 and the operation terminal 3, the operation stream in the video stream is controlled by the control processing means not shown in the operation terminal 3. Mode determination can be performed based on the presence or absence of a group of picture header. As a result, the shape of the mouse pointer can be switched between the high quality mode and the low delay mode.
[0035]
FIG. 11 shows a flow chart of a transition start for switching from the low delay mode to the high quality mode. When the operation button on the monitor screen is pointed and clicked with the mouse pointer (or cursor) (B1), the measurement is started and the operation is started. The measurement is ended by clicking the button (B2), and the operation amount from the measurement start to the measurement end is measured (B3). That is, by clicking the operation button, operations such as turning, zooming, and focusing of the camera 1 are performed. In the camera operation unit 13, the turning amount, zooming amount, and focusing distance by one operation are performed. Find the amount of movement.
[0036]
Then, the timer value corresponding to the obtained operation amount is calculated (B4), that is, the time until the mechanical operation is completed is calculated according to the turning control amount and zooming control amount of the camera. Then, the timer is started (B5), whether or not another operation has been performed is determined (B6), and if another operation has been performed before the timer has timed out, the process proceeds to step (B1). If there is no other operation, the transition to the high quality mode is started (B7). For example, transmission control of the switching instruction signal to the high quality mode shown in FIG. 4 is started.
[0037]
FIG. 12 is an explanatory diagram of mouse pointer shape control, including a low-delay mode display shape, a display shape indicating that switching to the high quality mode will soon be performed, a display shape during transition to the high quality mode, and a high quality mode display shape. The case of switching to the four stages is shown. While receiving low-delay mode video data from the video transmission device 2, the mouse pointer shape is set to the low-delay mode display format, but a display indicating that the high-quality mode will be switched soon after a lapse of a certain time from the final operation. Shape.
[0038]
During reception of low-delay mode video data from the video transmission device 2, the low-delay mode display shape is used as described above, and high quality is obtained after a certain time from the end of input operations such as camera turning and zooming by the camera operation unit 13. Change the mouse pointer display shape to indicate that the mode will be switched soon. Then, the display shape is changed to the high quality mode display shape by switching signal transmission, and the high quality mode display shape is changed by receiving the high quality mode video data from the video transmission device 2.
[0039]
FIG. 13 shows a flowchart of still image acquisition processing. In the operation terminal 3, still images are stored in the still image storage unit 12 at regular time intervals, and the remaining time until the still image storage timing is m. If it is seconds (C1), the current mode is determined (C2). In the case of the high quality mode, the transition to the low delay mode is suppressed until the still image acquisition (C3), and it is determined whether m seconds have elapsed. (C4) When the time has elapsed, a still image is acquired (C5). That is, the high-quality mode encoded data in the image decoding unit 10 is decoded, and a still image for one screen to be displayed on the video display unit 11 is stored in the still image storage unit 12.
[0040]
In step (C2), when the current mode is the low quality mode, the transition to the high quality mode by the switching instruction or the like is promoted (C6), and the current mode is determined thereby (C7), and the low delay is achieved. In the case of the mode, the process proceeds to step (C6), and when the mode is changed to the high quality mode, the process proceeds to step (C3), and the transition to the low delay mode is suppressed until the still image acquisition.
[0041]
FIG. 14 shows a processing flowchart of the control signal processing unit, and shows a main part of processing in the control signal processing unit 9 of the video transmission apparatus 2 of FIG. When receiving the camera operation signal from the camera operation unit 13 of the operation terminal 3 (D1), the control signal processing unit 9 determines the current mode (D2), and switches to the low delay mode in the high quality mode. A signal is sent to the mode selection unit 6 (D3), and a timer for a predetermined time is started (D4). If it is determined in step (D2) that the current mode is the low delay mode, the process proceeds to step (D4).
[0042]
Based on the time-out of the activated timer, the current mode is determined (D5). In the case of the low delay mode, a switch signal to the high quality mode is sent to the mode selection unit 6 (D6), and the camera control signal is sent to the camera. 1 to the control mechanism unit 4. If the current mode is the high quality mode in step (D5), the mode selection unit 6 is left as it is, and a camera control signal is sent to the control mechanism unit 4 of the camera 1.
[0043]
FIG. 15 is an explanatory diagram when the camera is turned. The monitored portion shown in FIG. 15A is captured by the camera 1 and displayed on the video display unit 11 of the operation terminal 3, and the display when the camera 1 is panned to the left. The state is shown according to the passage of time, and in that case, it is common to perform left panning with the left side as the gaze part. Therefore, the quantization scale on the left side in the screen shown in FIG. Improve display quality. In this case, the low-delay mode encoding unit 7 is selected by the mode selection unit 6 and encodes the video signal from the camera 1, but the left half of the screen is an intra block with a smaller quantization step. In the right half, control is performed to distribute non-intra blocks with a large quantization step. Such a control can also be controlled by determining the contents of the camera control signal because the quantization scale control for a predetermined block in one screen is possible. Thereby, it is possible to improve the image quality of the portion that is watched by the operator.
[0044]
FIG. 16 is an explanatory diagram of intra slice update, and FIG. 16A shows the update direction of the intra slice IS as time passes from top to bottom. When the intra slice IS is updated for one screen, a screen corresponding to the I picture is formed. Further, (B) shows a case where the update direction of the intra slice IS is changed with time from left to right.
[0045]
(C) indicates that most of the motion vectors in the motion compensation of the non-intra block created from the forward reference of the intra slice are in the right direction that matches the update direction of the intra slice. In this way, if the motion vector and the intra slice update direction are matched, the number of mismatches in IDCT (Inverse Discrete Cosine Transform) can be reduced, so the intra slice update is dynamically performed according to the turning direction of the camera. Control to change the direction is performed. Furthermore, it is possible to control so as to increase the number of intra-slice updates for the area corresponding to the gaze portion of the operator.
[0046]
FIG. 17 is an explanatory diagram of the zooming operation, and FIG. 17A shows that the gaze site of the operator when zooming in is the center portion of the screen even when time elapses. Therefore, as shown in (B), many intra blocks with fine quantization scales are distributed in the central area of the screen, and many non-intra blocks with coarse quantization scale are distributed in the peripheral area. Distribute. Thereby, the image quality of the central portion of the screen is improved. (C) shows the case of zooming out. Contrary to the case of zooming in (B), a large amount of non-intra blocks with a coarse quantization scale are distributed in the central area of the screen. A large number of intra-blocks with a small quantization scale are distributed in the peripheral area.
[0047]
FIG. 18 is an explanatory diagram of intra-slice update, P indicates a prediction coded picture, (A) is similar to the intra-slice update in the case of (A) in FIG. The case where the number of updates is increased upward is shown. In this case, when the camera is moved from the bottom to the top, the upper side of the screen becomes the gaze region, so that the image quality of the upper region of the screen can be improved. FIG. 18B shows an example of updating an intra slice corresponding to the case where the camera is moved from top to bottom in the opposite direction to FIG. In this case, the number of updates on the lower side of the screen is increased to improve the image quality of the gaze portion on the lower side of the screen.
[0048]
18C shows a case where the camera is turned to the left in the case of FIG. 16B, similar to the update of the intra slice, and the number of updates on the left side of the screen corresponding to the target region is increased. And improve the image quality on the left side of the screen. 18D shows a case where the camera is turned to the right as opposed to FIG. 18C. The number of updates on the right side of the screen corresponding to the target region is increased, and the image quality on the right side of the screen is improved. improves.
[0049]
FIG. 19 is an explanatory diagram of intra slice update during zooming. FIG. 19A shows a case of zooming in. Intra-slices indicated by hatched areas are controlled so as to increase in the central portion, and Improve image quality. Further, (B) shows the case of zooming out, and since the peripheral portion is the gaze portion, intra-slice update of the peripheral portion is increased to improve the image quality of the peripheral portion.
[0050]
The present invention is not limited to the above-described embodiments, and various additions and modifications can be made. Even in a system provided with a plurality of cameras, imaging is performed by designating a camera from an operation terminal. The present invention can also be applied to the case where the direction and the imaging range are controlled, and the video display unit 11 can also display a divided screen corresponding to the camera.
[0051]
(Supplementary note 1) Video transmission apparatus that compresses and transmits a video signal from a camera, and operation for decoding and displaying the compressed and encoded video signal received from the video transmission apparatus on the video display unit and controlling the camera In a video transmission system including a terminal, the video transmission device includes a low delay mode encoding unit that compresses and encodes a video signal from the camera, a high quality mode encoding unit, and the low delay mode encoding. Selection unit that switches between a high-quality mode encoding unit and a control signal processing unit that controls the mode selection unit to select a low-delay mode encoding unit when a camera control signal is received from the operation terminal And a video transmission system.
(Supplementary Note 2) The control signal processing unit of the video transmission apparatus receives and identifies a control signal for controlling the camera from the camera operation unit of the operation terminal, controls the mode selection unit, and controls a high quality mode. Supplementary note 1 characterized in that it is configured to switch from the encoding unit to the low-delay mode encoding unit and to switch from the low-delay mode encoding unit to the high-quality mode encoding unit after a series of control of the camera is completed. The video transmission system described.
[0052]
(Additional remark 3) The said camera operation part of the said operation terminal was equipped with the structure which sends out the instruction | indication signal of switching from a high quality mode to a low delay mode according to the prediction result by analyzing and predicting a camera operation input operation The video transmission system according to appendix 1 or 2, characterized by:
(Supplementary Note 4) The camera operation unit of the operation terminal has a configuration for displaying a mode indicating whether the mode is a high quality mode, a low delay mode, or a transition state according to a mouse pointer shape in the input operation unit formed on the monitor screen. The video transmission system according to appendix 1, 2 or 3, wherein
(Supplementary Note 5) The low-delay mode encoding unit of the video transmission apparatus has a configuration for controlling an intra block generation distribution according to a screen movement direction by controlling an imaging direction and an imaging range of the camera. The video transmission system according to any one of appendices 1 to 4, which is characterized by the following.
(Supplementary Note 6) The low-delay mode encoding unit of the video transmission apparatus has a configuration for controlling the frequency of intra-slice update according to the screen movement direction by controlling the imaging direction and imaging range of the camera. The video transmission system according to any one of appendices 1 to 5, which is characterized by the following.
[0053]
(Supplementary note 7) In a video signal transmission control method for controlling a camera from an operation terminal, compressing and encoding a video signal from the camera in a video transmission device, and transmitting the video signal to the operation terminal for display. In the process of controlling the imaging direction and imaging range of the camera, the video signal from the camera is compressed and encoded in the low delay mode and sent to the operation terminal, and then compressed and encoded in the high quality mode. A video transmission control method comprising a step of sending to the operation terminal.
(Additional remark 8) The process which switches the different mouse pointer shape to whether it is the said high quality mode, the said low delay mode, or mode transition is displayed on the input operation screen on the monitor screen which controls the said camera is included. The video transmission control method according to appendix 7, characterized by:
(Additional remark 9) In the process which controls the imaging direction and imaging range of the said camera, it includes the process which performs the compression encoding by the said low delay mode, and controls the generation | occurrence | production distribution of an intra block according to the direction of the motion of a screen. 9. The video transmission control method according to appendix 7 or 8, characterized in that it is characteristic.
(Additional remark 10) The process which performs the control which makes the frequency of the intra slice update according to the direction of the motion of the screen by control of the imaging direction and the imaging range of the camera high about the area | region on the opposite side to the direction of the motion of the screen is included. The video transmission control method according to appendix 9, wherein
[0054]
【The invention's effect】
As described above, the present invention is a process of changing the imaging direction or imaging range of the camera 1 by automatically switching from high quality mode encoding to low delay mode encoding when operating the camera 1. Can be displayed on the video display unit 11 of the operation terminal 3 with a small delay time. Thereby, it becomes possible to control the camera 1 appropriately. Further, when a series of operations of the camera 1 is completed, it is possible to automatically switch to high quality mode encoding, so that there is an advantage that the monitored portion can be displayed and monitored with high image quality.
[0055]
Also, as the encoding in the camera operation process, the intra slice update direction is controlled according to the control contents of the camera imaging direction or imaging range. For example, in the case of left turn, the intra slice update is performed from the left side. There is an advantage that the image quality of the screen on the left side of the gaze portion can be improved. Also, there is an advantage that the image quality of the gaze portion can be further improved by controlling the update frequency.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of an embodiment of the present invention.
FIG. 2 is an explanatory diagram when switching from a high quality mode to a low delay mode.
FIG. 3 is an explanatory diagram when switching from a low delay mode to a high quality mode;
FIG. 4 is an explanatory diagram of a control signal.
FIG. 5 is an explanatory diagram of a camera operation unit.
FIG. 6 is a schematic flowchart of processing of a camera operation unit.
FIG. 7 is an explanatory diagram of mouse pointer shape control.
FIG. 8 is an explanatory diagram of a LAN transmission format.
FIG. 9 is an explanatory diagram of an MPEG-2 video stream.
FIG. 10 is a schematic explanatory diagram of a video stream in a high quality mode and a low delay mode.
FIG. 11 is a flowchart of a transition to a high quality mode.
FIG. 12 is an explanatory diagram of mouse pointer shape control.
FIG. 13 is a flowchart of still image acquisition processing.
FIG. 14 is a processing flowchart of a control signal processing unit.
FIG. 15 is an explanatory diagram when the camera turns.
FIG. 16 is an explanatory diagram of intra slice update;
FIG. 17 is an explanatory diagram of a zooming operation.
FIG. 18 is an explanatory diagram of intra slice update.
FIG. 19 is an explanatory diagram of intra slice update during zooming.
[Explanation of symbols]
1 Camera
2 Video transmission equipment
3 Operation terminal
4 Control mechanism
5 Image encoding unit
6 Mode selection section
7 Low delay mode encoder
8 High quality mode encoder
9 Control signal processor
10 Image decoding unit
11 Video display
12 Still image storage
13 Camera control unit

Claims (4)

A video transmission apparatus that compresses and transmits a video signal from a camera, and an operation terminal that decodes and displays the compressed and encoded video signal received from the video transmission apparatus on a video display unit and controls the camera In video transmission systems,
The video transmission device receives a video signal from the camera and compresses and encodes using an intra frame, and inputs the video signal of the camera, and the imaging direction and imaging of the camera. mode selection unit for switching range and low latency mode encoding unit for compression coding by distributed more intra blocks to the movement direction of the screen under the control of, and the high-quality encoding unit and the low-delay mode encoding unit And a control signal processing unit that receives a control signal for controlling the imaging direction and imaging range of the camera from the operation terminal and causes the mode selection unit to select the low-delay mode encoding unit. Video transmission system. The video transmission system according to claim 1, wherein the low-delay mode encoding unit has a configuration for controlling the distribution of intra blocks in units of intra slices . In a video signal transmission control method of controlling a camera from an operation terminal, compressing and encoding a video signal from the camera by a video transmission device, transmitting the video signal to the operation terminal, and decoding and displaying on the operation terminal.
In the process of controlling the imaging direction and imaging range of the camera from the operation terminal, a large number of intra blocks are distributed with respect to the moving direction of the screen by controlling the imaging direction and imaging range of the camera. The low-delay mode encoding unit that performs compression encoding is compressed and encoded and sent to the operation terminal. After that, the high-quality mode encoding unit that performs compression encoding using an intra frame performs compression encoding to the operation terminal. Including the process of sending
And a video transmission control method. 4. The video transmission control method according to claim 3, wherein the compression encoding by the low delay mode encoding unit includes a control process for increasing the distribution of the intra block in units of intra slices.

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