JPH047977A - Compressed picture data transmitting system - Google Patents

Abstract

PURPOSE:To enable high-speed retrieval without adding any hardware to a terminal by providing first and second transmission modes and transmitting the respective still picture data of N frames in the second transmission mode while compressing the information at much higher compressibility than that of the first transmission mode. CONSTITUTION:The first transmission mode is a normal transmission mode to display the still picture of one frame as one picture at the terminal. In the second transmission mode, the still picture data of N frames are respectively transmitted after synthesizing the picture compressed to 1/N much higher than that of the first transmission mode to a picture data equivalent to one picture. Thus, at the terminal, the still pictures of N frames are simultaneously displayed within one picture as reduced pictures. A user can grasp the picture contents of a lot of source still pictures at a glance by observing this multiple picture. The transmission mode information obtains 0000bit contents in the normal mode, 1111 in the multiple picture mode, further, the significant number of reduced pictures in the multiple picture mode, 0000 when four frames are defined as one picture, 0001 with light frames as one picture and 0010 with 16 frames as one picture.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to still image transmission/
In particular, the present invention relates to a compressed image data transmission method that improves search efficiency.

[Prior art] In an information retrieval type videotex competition system, information on both still images stored in an information center is selectively read out in response to a request from a user, and transmitted via a telephone line. The information is transmitted to the user terminal device. As still images provided by such Videotex systems,
Recently, natural images with high resolution comparable to photographs have become indispensable. However, since the amount of information in natural images is enormous, highly efficient information compression is required, and the transform encoding method for this purpose is a combination of discrete cosine transform (DCT) and scalar quantization (SQ). Things are often used.

[Problem to be solved by the invention] By the way, when a user searches for still image information in a Videotex system, conventionally a table of contents (text information) listing searchable still images is transmitted from a center to a terminal device. However, when the user selects a desired still image by number or the like from the table of contents, the center transmits the image data of the selected still image to the terminal device. However, with this search method, each still image is searched from the text information in the table of contents.

In particular, it was difficult to grasp the image (image content) of a natural image, so the still image displayed on the screen after selecting a number was sometimes different from what the user intended, and it took a lot of time to search.

The present invention has been made in view of these problems, and it is an object of the present invention to provide a compressed image data transmission method that enables high-speed searching without requiring the addition or expansion of special hardware on the terminal side.

[Means for Solving the Problems] In order to achieve the above object, the compressed image data transmission method of the present invention compresses still image data stored in a center and then transmits the compressed image data to a terminal via a communication line. In the system, the first transmission mode transmits one frame of still image data as one screen's worth of image data, and the first transmission mode transmits one frame of still image data as one screen's worth of image data, and one screen's worth of image data by combining N frames (N is an integer of 2 or more) of still image data. In the second transmission mode, each of the N frames of still image data is compressed at a higher compression rate than in the first transmission mode.

Additionally, in order to allow the terminal user to immediately pull out the normal still images corresponding to the reduced screens, information for identifying the original still images corresponding to each reduced screen is added and transmitted.

[Action frame] The first transmission mode in which one frame of still image data is transmitted as one screen's worth of image data is a normal transmission mode in which the terminal device displays one frame of still image as one screen.

The second transmission mode replaces the conventional table of contents based on text information, and compresses each N frame of still image data at a higher compression rate than the first transmission mode (normal mode). /N, and these reduced screens are combined into one screen's worth of image data and then transmitted. As a result, N frames of still images are simultaneously displayed on one screen as a reduced screen on the terminal device. By viewing this multi-screen, the user can grasp the image contents of a large number of original still images at a glance.

In addition, when transmitting information that identifies the original still image corresponding to each reduced screen, such as a still image number,
When you select the number information from the terminal device and return it to the center,
Based on the number information, the center immediately transmits the original still image corresponding to the selected reduced screen to the terminal device in a normal mode, and the original still image is thereby displayed on the terminal screen.

[Embodiment] FIG. 1 shows a transmission format of a Videotex system to which an embodiment of the present invention is applied.

In this embodiment, there are two modes: a normal mode (A) in which one frame of still image information is transmitted, and a multi-screen mode (B) in which N frames of still image information are combined into one frame and transmitted for high-speed search. There is a transmission mode. Which transmission mode is used?
Upper 4 bits of byte [Transmission mode controller 14A, 14B
It is expressed as

That is, as shown in FIG. 2, this [transmission mode information is [0000] in the normal mode and [1111] in the multi-screen mode. In multi-screen mode,
Furthermore, the lower 4 bits [the number of reduced images becomes significant; for example, when 4 reduced images are combined into one screen as shown in Figure 3 (A), [0000], as shown in Figure 3 (B). To combine 8 reduced frames into one screen, select [0
001], and when 16 reduced frames are combined into one screen as shown in FIG. 3(C), the bit content is [0010. In addition, in FIG. 3, numbers 1, 2, .・・・・・・
represents the position (quadrant) of the reduced screen.

Again in FIG. 1, the multi-screen mode (B) is quadrant 1,
2. NOl of the original still image corresponding to each reduced screen of ...
Information representing is added (30B to 36B). moreover,
Quadrant 1, 2. The image data of each reduced screen of ... is DC
Given as T-8Q data, (44B, 48B, ・
), information representing the data length of those image data is also added (40B, 46B, etc.). When the number of reduced screens is N, the image data of each reduced screen is compressed to an image of 1/N size compared to the normal mode image data (50A) by thinning reduction and increasing the compression rate of DCT-8Q. .

In the transmission information common to both modes (A) and (B),
The first [DCT-8Q identification code 10A, IOB is
This indicates that the subsequent image data is image data compressed using the DCT-8Q method. [Data length of entire image] 12A and 12B represent the data length of one entire screen of this DCT-8Q compressed image data. [Transmission type] 18A
, 18B indicates whether to transmit each block data in ascending order of stage number or in order of block arrangement regardless of stage number. , which gives the number of the first stage to be sent. [
The original signal type 12OA, 20B is the original signal type Y,
Indicates whether they are U and V components or R, G, and B components. [Screen start point columns 22A and 22B and [screen size column 24A and 24B] are used when displaying the still image embedded in a character screen. [SQ station Tsubu mode 1
2E3A and 26B represent step sizes of SQ (scalar quantization). [Signal component effective bi-sotoco 28A, 2
8B is Y component only, Y component and U component only, Y component and V
This is to enable transmission of only the components, Y, U, V
Indicates whether each component is valid or invalid.

In normal transmission mode (A), [Signal component valid pitco 2
After 8A, one frame of still image data for one screen is DCT-
It is given as 8Q data.

In this way, in the multi-screen mode, each N-frame still image data is transmitted as image data of a reduced screen reduced to 1/N by information compression with a higher compression rate than in the normal mode. In a terminal device, a large number of reduced screens are displayed simultaneously within one screen, as shown in FIG. Therefore, the terminal user can visually grasp the images (image contents) of a large number of original still images through these reduced screens. Then, when the user selects the desired reduced screen by quadrant number, screen No. 8 corresponding to the reduced screen is sent to the center station, and the center station selects the screen No. 8 corresponding to the reduced screen.
Still image information of 0 is sent in normal mode (A). As a result, one frame of the original still image is displayed as one screen on the terminal device.

In this way, according to this embodiment, a multi-screen table of contents is provided to the terminal user instead of a conventional table of contents based on text information, making it easy to view the contents of still image information stored at the center. information and can be searched quickly. In addition, the NO0 of the original still image corresponding to each reduced screen
By sending the information to the terminal device, the user can retrieve still image information for one screen corresponding to the desired reduced screen from the center station, allowing the user to accurately capture still images such as natural images in a short time. Can be searched.

Note that this embodiment uses the Videotex 0 system's DCT-
Although the present invention is applied to the 8Q method, the present invention is not limited to this, and can be applied to other still image transmission systems, and other information compression methods can also be used. For example, the present invention can be applied to a display system with a large screen. Even greater search effects can be obtained when applying this method to large-scale multi-screen natural image searches.

[Effects of the Invention] The present invention provides the following effects by having the stem and knob as described above.

According to the compressed image data transmission method of claim 1, in addition to the normal first transmission mode, in the second transmission mode, N-frame still image data is transmitted from a huge amount of still image data stored at the center. By compressing information at a higher compression rate than in the first transmission mode and transmitting it as reduced screen image data, the terminal device can simultaneously display N frames of still images on one screen as reduced screens. Therefore, by viewing this multiple screen, the terminal user can grasp the image contents of a large number of original still images at a glance, and can search the still image database of the center station quickly and accurately.

According to the compressed image data transmission method of claim 2, information for identifying the original still image corresponding to each reduced screen is added together with the image data of the N-frame reduced screen highly compressed as described above. By transmitting the information, the terminal device can return the identification information related to the desired reduced screen to the center, and the center can immediately send the original still image corresponding to the reduced screen in the first transmission mode, making it easier to use the terminal. Users can immediately retrieve desired still image information at any time.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the transmission format of a Videotex system to which an embodiment of the present invention is applied, and FIG. A diagram showing a content example and FIG. 3 are diagrams showing the number and display format of reduced images displayed on the terminal device in the multi-screen mode of the embodiment. 14A, 14B... [Transmission mode 1 reduced screen number information 30B to 36B...Screen numbers for quadrants 1 to n, information 42B, 48B... Image data of compressed screen, 50A
...Image data in normal mode.

Claims (2)

[Claims] (1) In a system that compresses still image data stored at a center and then transmits it to a terminal via a communication line, the first transmission mode transmits one frame of still image data as one screen worth of image data. and a second transmission mode in which still image data of N frames (N is an integer of 2 or more) are combined and transmitted as image data for one screen. A compressed image data transmission method characterized in that each still image data is compressed at a higher compression rate than in the first transmission mode. (2) The compressed image data transmission method according to claim 1, wherein information for identifying the original still image corresponding to each reduced screen is added and transmitted in the second transmission mode.