JPH0484585A - Still picture transmission display device - Google Patents

Abstract

PURPOSE:To reduce the transmission time by using a filter section and a coding section so as to reduce a still picture of a television camera and apply compression coding processing to the reduced still picture. CONSTITUTION:A reduced still picture from a filter section 4 is given to a changeover switch 5 switched alternately at a prescribed period, a 1st reduced still picture is stored in a 1st reduced still picture memory section 6 and a succeeding still picture is stored in a 2nd reduced still picture memory 7, and a succeeding reduced still picture is stored any of the 1st or 2nd reduced still picture memory 6 or 7 based on the changeover switch 5 and transferred alternately to a coding section 8. The reduced still picture of the 1st reduced still picture memory section 6 is subject to compression processing based on the set compression data based on a difference between the picture element of the succeedingly inputted reduced still picture and the picture element of the still picture subject to compression processing just before. The still picture is subject to decoding processing by the decoding section 13 and expanded to be a same size as that of the reduced still picture and displayed on a TV monitor. Thus, the transmission time is reduced.

Description

[Detailed description of the invention] [Industrial application fields] The present invention relates to an improvement of a still image transmission device.

[Prior Art] Conventionally, this type of device has been disclosed in, for example, Japanese Patent Application Laid-Open No. 58-80989.
No. Publication, JP-A-61. -1.79693, etc. In Japanese Unexamined Patent Publication No. 58-80989, an electric rotating pan head is controlled so that the direction of the television camera is at a preset position, and by this control, the direction of the camera can be adjusted without fine adjustment. A scene at a predetermined position is displayed on a television monitor.

Furthermore, in Japanese Patent Application Laid-open No. 179693/1984, a video switch for selecting image signals sent from a plurality of television cameras and a sequence control circuit for controlling the switch are provided, and these are configured to provide desired output. By switching and outputting images and storing them in a predetermined memory area of the image memory, a desired image can be updated at any timing.

[Problems to be Solved by the Invention] In the conventional still image transmission device as described above, since a camera control function and a video switch function are required on the transmission side, the mounting area of the video input section in the device increases. There was a problem. Furthermore, even when monitoring one location for a long time, the entire screen is compressed for each scene, which takes time to transmit, and it also makes it easier to compare past scenes and current scenes at one monitoring point. There was a problem that I could not go to.

The present invention was made in order to solve such problems, and it is possible to smoothly compare a past scene and a current scene without increasing the mounting area of the device or requiring transmission time. The purpose is to obtain a transmission display device.

[Means for Solving the Problems] A still image transmission and display device according to the present invention includes a first frame memory section that stores an image signal of a television camera converted into a digital signal as a still image, and a preset reduction a filter section that reduces the still image in the first frame memory section based on the ratio; a changeover switch that transfers the still images separately; and a first reduced still image memory section that receives the odd-numbered reduced still images from the filter section via the changeover switch and stores the reduced still images one by one. a second reduced still image memory section into which even-numbered reduced still images from the filter section are input via the changeover switch and stores the reduced still images one by one; and the first and second reduced still images. Reduced still images in the still image memory section are input alternately, and when the first reduced still image is input, the reduced still image is compressed based on preset compression data, and then the reduced still images that are subsequently input are an encoding unit that performs compression processing on the image based on the difference between the pixel of the image and a pixel of a still image that has been compressed immediately before, and sequentially encodes the compressed still image and transmits the compressed still image; a decoding unit that decodes and expands the still image compressed and encoded by the encoding unit to make it the same size as the reduced still image; and a decoding unit that has a capacity in advance for storing the reduced still image of the decoding unit. A second frame that shifts the stored reduced still image and cancels the first reduced still image when the latest reduced still image is input when the reduced still image is stored and the capacity is filled. The apparatus includes a memory section and a television monitor that displays a plurality of reduced still images stored in the second frame memory section in chronological order.

[Operation] In the present invention, when an image signal from a television camera converted into a digital signal is stored in the first frame memory section as a still image, the filter section converts the still image into a digital signal based on a preset reduction ratio. is reduced and transferred to the first and second reduced still image memory sections via a changeover switch.

The reduced still images that are successively transferred from the filter section are transferred to the first reduced still image memory section, and the next still image is transferred to the first reduced still image memory section by means of a changeover switch that is switched alternately at a predetermined cycle. The image is stored in the reduced still image memory section No. 2. At this time, the first reduced still image is transferred to the encoder, so
The third reduced still image is stored in the first reduced still image memory section. In this manner, subsequent reduced still images are stored in either the first or second reduced still image memory section and alternately transferred to the encoding section based on the operation of the changeover switch.

The encoding section first performs compression processing on the reduced still image in the first reduced still image memory section based on preset compression data. Thereafter, the compressed still image that is subsequently input is subjected to compression processing based on the difference between that pixel and the pixel of the still image that was compressed immediately before. Then, the compressed still images are sequentially encoded and transmitted.

The still image that has been compressed and encoded by the encoding unit is decoded and expanded by the decoding unit to have the same size as the reduced still image, and is transferred to and stored in the second frame memory unit. be done. The plurality of reduced still images sequentially stored in the second frame memory section are displayed on a television monitor in order from the newest still image. At this time, when a new reduced still image is stored in the second frame memory section, the oldest reduced still image displayed on the TV monitor disappears from that monitor, and at the same time, other reduced still images are shifted to the new reduced still image. A reduced still image is projected.

[Embodiment] FIG. 1 is a block diagram of a still image transmission and display device showing an embodiment of the present invention, and FIG. 2 is a diagram showing an example of a reduced still image displayed on a television monitor.

In the figure, (1) is a television camera, (2) is an A/D converter that converts the image signal of the television camera (1) into a digital quantity, and (3) is an image signal that is controlled by the CPU (10). The first frame memory section (4) stores a still image (one frame of a still image), and the first frame memory section (4) reduces the still image in the first frame memory section (3) based on the reduction ratio set in the CPU (10). The filter section (5) is a changeover switch that is alternately switched under the control of the CPU (10).

(8) and (7) are first and second reduced still image memory sections that store the reduced still images of the filter section (4) one frame at a time;
Among these, an odd number of reduced still images are input to the first reduced still image memory section (6) by the changeover switch (5), and the second
Even-numbered reduced still images are input to the reduced still image memory section (7).

(8) is an encoding unit in which the reduced still images of the first and second reduced still image memory units (8) and (7) are input alternately, and when the first reduced still image is input, the reduced still image is The image is compressed (DCT: Discrete Cosine Transform) based on preset compression data, and then, for the subsequently input reduced still image, the pixel of that pixel is compared with the pixel of the still image that was compressed immediately before. Perform compression processing based on the difference. and,
Entropy encoding such as Huffman encoding is performed on the compressed still images and the images are sequentially transmitted. The DCT is a process performed on a block of n pixels x own pixel, and the more average the pixel values within the block, the greater the compression effect!
I can do it.

(9) is the transmission line (II) for compressed and encoded still images.
Still image transmission control unit (12) transmits to the transmission line (1
1) a still image reception control unit that receives the still image transmitted to
(13) is a decoding unit that decodes and expands the still image sent through the still image reception control unit (12) to create a reduced still image of the size before transmission.

(14) is a second frame memory section, and a decoding section (13
) The capacity for storing reduced still images is set in advance.

When the reduced still images are stored to fill the capacity, and the latest reduced still image is input, the stored reduced still images are shifted and the first reduced still image is canceled. (15) is D
/A converter, (16) is cpu, still image reception control unit (
12) Performs control to start, stop, or interrupt the operation of the decoding unit (13) and the second frame memory unit (14). It also has a function of sequentially transferring a plurality of reduced still images stored in the second frame memory section (14) to the television monitor (17).

Note that CPU (], 0) and CPU (1, 6) operate based on the operation of an operating device (not shown). CPU
The reduction ratio in (10) is set by the controller, and the number of frames of the reduced still image stored in the second frame memory section (14) is set by the CPU (1B). Changes are made using the manipulator.

The operation of the still image transmission and display device configured as described above will be explained. Still images from the television camera (1) sent via the A/D converter (2) are sent to the CPU (In)
Under the control of , the frames are sequentially stored in the first frame memory section (3) and transferred to the filter section (4).

The filter section (4) performs filtering to reduce the still image based on the reduction ratio set in the CPU (10). The first reduced still image is sent out in synchronization with the operation of the changeover switch (5) and stored in the first reduced still image memory section (B). Since the first and second reduced still image memory units (6) and (7) can only store one reduced still image, the next reduced still image can be stored in the second reduced still image by switching the switch (5). It is stored in the memory section (7). At this time, the reduced still image in the first reduced still image memory section (8) is transferred to the encoding section (8), so the subsequently transmitted reduced still image is stored in the first reduced still image memory section. 6). In this way, the reduced still image to be sent out is stored in the first and second reduced still image memory sections (6), (
7) are alternately stored and transferred. Encoding section (
In step 8), when the first reduced still image is input, the reduced still image is compressed based on preset compression data. In addition, compression processing is performed on the subsequently input reduced still image based on the difference between the pixel of the reduced still image and the pixel of the still image that was compressed immediately before.

Then, the compressed still images are sequentially encoded and transferred. Still images that have been compressed and encoded are processed by the CPU
Under the control of (10), the still image is transmitted to the transmission line (11) via the still image transmission control section (9).

When the still image reception control unit (I2) receives the transmitted still image, the decoding unit 13 decodes the compressed still image, expands it, and transmits it under the control of the CPU (10). The still image is reduced to the previous size and transferred to the second frame memory section (14). Second frame memory section (
14) sequentially stores the decoded reduced still images. At this time, the last stored reduced still image is the latest in terms of time, so the reduced still image displayed on the TV monitor (I7) is controlled by the CPU (10) as shown in Figure 2. The latest reduced still image is displayed at position 1, and the oldest reduced still image is displayed at position 16.

[Effects of the Invention (1)] 2 As described above, according to the present invention, the filter section and the encoding section reduce the still image of the television camera, and also perform compression and encoding processing on the reduced still image. I decided to do this, so
The effect is that the transmission time for one reduced still image is shortened. Furthermore, since the transmitted reduced still images are displayed in chronological order on a television monitor, it is also possible to see the movement of the subject and the history of the scene at a glance.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a still image transmission and display device showing an embodiment of the present invention, and FIG. 2 is a diagram showing an example of a reduced still image displayed on a television monitor. In the figure, (1) is a television camera, (2) is an A/D converter, (3) is a first frame memory section, (4) is a filter section, (5) is a changeover switch, and (6) is a first frame memory section. 1 is a reduced still image memory section, (7) is a second reduced still image memory section, (
8) is an encoding unit, (9) is a still image transmission control unit, (12)
(13) is a still image reception control section, (13) is a decoding section (14) is a second frame memory section, (I5) is a D/A converter, (1
, 7) is a television monitor.

Claims (1)

[Claims] A first frame memory section that stores an image signal of a television camera converted into a digital signal as a still image; and a still image stored in the first frame memory section based on a preset reduction ratio. a filter unit that reduces the size; a switch that is alternately switched at a predetermined period and separately transfers odd-numbered reduced still images and even-numbered reduced still images among the reduced still images of the filter unit; and the filter Odd-numbered reduced still images from the filter section are inputted via the changeover switch, and a first reduced still image memory section stores the reduced still images one by one, and even-numbered reduced still images from the filter section are input. A second reduced still image memory section that is input via the changeover switch and stores the reduced still images one by one, and reduced still images of the first and second reduced still image memory sections are inputted alternately; When the first reduced still image is input, the reduced still image is compressed based on the preset compression data, and then for the subsequently input reduced still images, that pixel and the previous compression processing are performed. an encoding unit that performs compression processing based on the difference between the pixels of the still image and sequentially encodes the compressed still image and transmits the encoded still image; a decoding unit that decodes and expands the image to have the same size as the reduced still image; and a capacity for storing the reduced still image of the decoding unit is set in advance, and the capacity is filled by storing the reduced still image. When the latest reduced still image is input at the same time, a second frame memory section shifts the stored reduced still image and cancels the first reduced still image; 1. A still image transmission and display device comprising: a television monitor that displays a plurality of reduced still images in chronological order.