JPH09214961A - Image data communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image data communication system for which a new compression system is used for sufficiently transmitting required information as a whole image while providing high-speed image data communication. SOLUTION: At a transmitter 10, a border line L in an image G is detected from image data by a boundary detecting means 12 and while sizing minimum a block containing the border line L, the image data are divided into plural blocks by a dividing means 13. The positions of respective blocks in the image are detected by a position detecting means 17, the average luminance values of respective blocks are detected by a luminance value detecting means 18, and the luminance patterns of respective blocks are detected by a luminance pattern detecting means 19. While using a previously set reference luminance pattern, a rotary angle detecting means 20 detects a rotary angle θ where the reference luminance pattern corresponds to the luminance patterns of respective blocks. Data containing these position, average luminance value and rotary angle for each block are transmitted to a receiver 30 as the data of respective blocks by a transmitting means 15 and at the receiver 30, a source image is reproduced by performing inverse processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for compressing image data divided into a plurality of blocks and transmitting the compressed image data from a transmitting device to a receiving device, and more particularly, to show correspondence between image data of each block and a reference luminance pattern. The present invention relates to an image data communication system that performs compression processing by converting the data into the data shown.

[0002]

2. Description of the Related Art An image data communication system for transmitting a still image or a moving image from a transmitting device to a receiving device is used for various information communications, and various wired or wireless methods are also used for image data communications. ing. In such image data communication, the image data is divided into a plurality of blocks, compressed by discrete cosine transform or the like, and transmitted, which reduces the amount of data to be communicated.

[0003]

Various methods such as the JPEG method and the MPEG method have been proposed and put to practical use for the compression of image data, but they are required in view of the characteristics of the image data. It is expected that an effective compression method that can further reduce the amount of communication data while maintaining high image quality will be developed.

According to the present invention, if the boundary line such as the contour line in the image is clear, even if the other part such as the background part in the image is somewhat unclear, the information necessary for the entire image is sufficient. The present invention has been made paying attention to the fact that it can be transmitted to an image data communication system using a novel compression method.

[0005]

In order to achieve the above-mentioned object, an image data communication system according to the present invention compresses image data divided into blocks composed of a plurality of pixels by a transmitter using a reference luminance pattern. Then, the compressed data is transmitted to the receiving device. That is, in the transmitting device, the boundary detecting means detects the boundary line in the image from the input image data, and the block including the boundary line is set to the minimum size, and the dividing means divides the input image data into a plurality of blocks. . Then, the position detecting means detects the position in the image of each block, the brightness value detecting means detects the average brightness value of each block, and the brightness pattern detecting means detects the brightness pattern of each block, Also,
The rotation angle detecting means detects the rotation angle corresponding to the reference luminance pattern and the luminance pattern of each block using the preset reference luminance pattern. The data including the position of each block, the average brightness value, and the rotation angle is data representing the image content of each block based on the reference brightness pattern, and these data are transmitted to the receiving device by the transmitting means as the data of each block. To do.

In the receiving device, the data of each block transmitted from the transmitting means is received by the receiving means, and the luminance value of the reference luminance pattern is corrected by the luminance value correcting means according to the average luminance value of each received block data. To do. Furthermore, the rotation processing means reversely processes each of the brightness-corrected reference brightness patterns in accordance with the rotation angle of the corresponding block data, and changes the reference brightness pattern to an angle representing the content of the block data. Reconstructing means arranges the reference luminance patterns that have been value-corrected and subjected to the reverse rotation processing in accordance with the positions of the corresponding block data to reconstruct the original image.

Here, the reference luminance pattern used in the transmitter and the reference luminance pattern used in the receiver are the same pattern, and the transmitter and the receiver perform compression processing and decompression processing using the same reference luminance pattern. To do. This reference luminance pattern may be stored in the memory in advance in the transmitting device and the receiving device and set, or the transmitting device may transmit the reference luminance pattern to the receiving device when transmitting data. Further, the reference luminance pattern may have different sizes and patterns for each block size, but it is also possible to use reference luminance patterns having the same size and pattern regardless of the block size.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An image data communication system according to an example of the present invention will be described with reference to the drawings. As shown in FIG. 1, the image data communication system includes a transmission device 10 and a reception device 30, and wirelessly transmits the image data compressed by the transmission device 10 to the reception device 30. The image data may be transmitted from the transmitting device 10 to the receiving device 30 using a wired line such as a telephone line, and whether to transmit the image data wirelessly or by wire is arbitrarily set as necessary.

Input means 11 for inputting image data to be transmitted, boundary detection means 12 for detecting a boundary line in an image from the image data input by the input means 11 are input to the transmission device 10. A block dividing unit 13 that divides the image data into a plurality of blocks, a compressing unit 14 that compresses the divided data of each block using a reference luminance pattern, a position of each block, an average luminance value, and a rotation. The transmission means 15 for transmitting the compressed data for each block including the angle is provided.

The input means 11 is composed of an image pickup device and a memory for accumulating image data, and inputs the image data to the boundary detection means 12. The boundary detecting means 12 scans the image data for each image and detects the contour line in the image as a boundary line. In this boundary line detection processing, the image is scanned in the x-axis direction and the y-axis direction, the brightness values thereof are accumulated, and a position where the change in the brightness value is steeper than a predetermined value is detected as the position of the boundary line.

That is, as shown in FIG. 2 (a), the luminance value of the image G is accumulated while scanning along the line AA in the x-axis direction, and the accumulation processing of the luminance value is performed by AA. The line is repeated while sequentially moving in the y-axis direction to obtain the change in the brightness value of the image G in the x-axis direction. Also, y in image G
Similarly, the change of the brightness value in the axial direction is B-
The brightness values along line B are accumulated while scanning in the y-axis direction,
This brightness value accumulation processing is repeatedly performed while sequentially moving the BB line in the x-axis direction. In the example of the image G including the circular boundary line L as shown in FIG. 2A, the change in the luminance value I along the line AA and the line BB passing through the center of the image G is the same. As shown in (b) and (c), the position coordinates of a1 and a2 and b1 and b2 at which the brightness value I sharply rises are detected as the position of the boundary line L. Therefore, the position coordinates Ab between the line AA and the line BB
And Ba, the position coordinates of the boundary line L are (a1, Ab) and (a2, Ab) and (Ba, b1) and (Ba, b2).
Detected as.

The block dividing means 13 comprises a size determining means 16 for determining the size of a block when dividing the image data, and a position detecting means 17 for detecting the position coordinates of each block in the image. The image data is divided into a plurality of blocks so that the part including the boundary line L, which is detected by the boundary detection means 12, is a block of the smallest size.
In this embodiment, the block size is 4 pixels × 4 pixels, 8 blocks.
Three types of pixels × 8 pixels and 16 pixels × 16 pixels are determined, and the size determining unit 16 determines the block including the boundary line L based on the detected position of the boundary line L, as shown in FIG. The minimum size of 4 pixels × 4 pixels, the block adjacent to the minimum size block is determined to have a size of 8 pixels × 8 pixels, and the block outside thereof is determined to have a size of 16 pixels × 16 pixels, and the boundary line L is small. The image is divided into blocks and larger blocks toward the background. The blocks may overlap each other in the image, or may be set so as to be adjacent to each other without overlapping each other. Which one is set is arbitrarily determined from design considerations.

Further, the position detecting means 17 detects the position coordinates of each divided block, and detects the position coordinates such as the upper left corner and the center of each block as the coordinates for specifying the position of each block in the image. To do. Compression means 14
Is based on the brightness value detecting means 18 for calculating the average brightness value of each divided block, the brightness pattern detecting means 19 for detecting the distribution pattern of the brightness in each block, and the brightness pattern of each detected block. A rotation angle detecting means 20 for detecting a rotation angle for matching the luminance distribution pattern is provided, and the data of each block is converted into data based on the reference luminance pattern and compressed.

As shown in FIG. 4A, for example, 4 pixels × 4
Taking a block of pixels as an example, the luminance pattern detecting means 1
Reference numeral 9 indicates that the block of 16 pixels is divided into regions of 4 pixels each as shown in FIG.
1, I2, I3 and I4 are detected and detected as a luminance value distribution pattern as shown in FIG. That is, the data of each block is collected for each block size as shown in FIG. 5 in the process of the compression process, and is converted into data including position coordinates (x, y) and a luminance distribution pattern. In the present embodiment, the brightness value detecting means 18 calculates the average brightness value of the block using these brightness values I1, I2, I3 and I4, and calculates (I1 + I2 + I3 + I4) / 4 as the average brightness value of the block.

The rotation angle detecting means 20 identifies several kinds of reference luminance patterns by an identifier (ID) and holds them in a memory. The reference luminance pattern and the luminance pattern of the block are compared with each other to compare the luminance of the blocks. When the pattern is rotated about its center C, it is detected which reference luminance pattern the rotation angle θ corresponds to. The reference luminance pattern is, for example, as shown in FIG. 6A, a pattern in which four regions having mutually different luminance values are combined. As a result of the above processing by the compression means 14, as shown in FIG. 6B, the data of each block are collected for each block size, and the position coordinates (x,
y), the reference ID indicating the corresponding reference luminance pattern, the rotation angle θ, and the average luminance value are converted into data. That is, the pixel data of each block is used as the reference luminance pattern I.
The data amount is converted to D, the rotation angle θ, and the average luminance value to significantly reduce the data amount. The transmission unit 15 modulates the data of each block compressed and converted by the compression unit 14 as described above, and sequentially transmits the data as a signal adapted to the line.

On the other hand, the receiving device 30 receives the compressed data of each block from the transmitting device 15 and demodulates it, and the compressed data of each block is expanded using the same reference luminance pattern as the transmitting device 10. Extension means 32
Reconstructing means 33 for rearranging the decompressed data of each block to reconstruct the original image, and output means 34 for outputting the reconstructed image data.

The decompressing means 32 holds several kinds of reference luminance patterns which are the same as those of the compressing means 14 in the memory in correspondence with IDs, and generates the corresponding reference luminance patterns based on the reference IDs in the received block data. The reference data is specified and the block data is expanded using this reference luminance pattern.
The decompression unit 32 corrects the brightness value of the reference brightness pattern based on the average brightness value in the block data.
5 and rotation processing means 36 for performing reverse rotation processing on the reference luminance pattern based on the rotation angle θ in the block data. That is, the correction means 35 corrects the reference brightness pattern having the matched pattern to the brightness of the original block using the average brightness value, and the rotation processing means 36 uses the rotation angle θ to reversely rotate the reference brightness pattern. To the same state as the original block.

The reconstructing means 33 rearranges the luminance-corrected and inverse-rotated reference luminance pattern at the position indicated by the coordinates (x, y) in the received block data, and the original image is formed by these reference luminance patterns. Reconstruct. The output means 34 is composed of a display device, a memory for accumulating image data, and the like, and displays, accumulates and holds the reproduced image after being reconstructed.

According to the image data communication system having the above structure, the boundary line L in the image of the image data input from the input means 11 of the transmission device 10 is detected by the boundary detection means 12, and the block division means 13 detects the boundary line L. The portion including L is divided into a plurality of blocks as the minimum size, and the position coordinates (x,
y) is detected. Then, the compression unit 14 detects the average brightness value and the brightness pattern of each block, and also detects the rotation angle θ with respect to the corresponding reference brightness pattern. That is, the data of each block is the position coordinate,
The data is converted into data including the reference brightness pattern ID, the average brightness value, and the rotation angle θ, and these data are sequentially transmitted to the receiving device 30 by the transmitting unit 15.

With respect to the data of each block received by the receiving means 31 of the receiving device 30, a reference luminance pattern is specified by the decompressing means 32, and the reference luminance pattern is subjected to luminance value correction and reverse rotation processing to obtain each block. Each image data is expanded. The image data of each block is rearranged by the reconstructing unit 33 to reproduce the image data of the original image and output by the output unit 34. It is expected that the reproduced image will not be a complete reproduction of the original image because the conversion is performed based on the reference luminance pattern. However, since the boundary line L portion such as the contour line is converted into fine blocks for conversion, faithful reproduction can be performed by conversion based on the reference luminance pattern, so that the information of the original image is faithfully reproduced as the entire reproduced image. Can be transmitted to.

In the present invention, the boundary line L can be detected by using various known methods.
It is also possible to compare the brightness between pixels and detect a portion having a brightness higher than a predetermined threshold value as a boundary line. Further, in the present invention, the block size and the number of types thereof can be arbitrarily set in consideration of the design, and the block including the boundary line may be set so as not to be larger than the blocks in other image areas. That is, the block size is 1
The size determining means 16 can be omitted in this case. Further, in the present invention, the type and the number of reference luminance patterns can be arbitrarily set from the viewpoint of design, for example, several types of reference luminance patterns can be set for each block size, or It is also possible to use one type of reference luminance pattern regardless of the size and detect the luminance pattern of the block in a format that matches the reference luminance pattern regardless of the block size.

Further, in the present invention, the reference luminance pattern is transmitted prior to the transmission of data from the transmitting device without holding the reference luminance pattern on the receiving device side, or
The corresponding reference luminance pattern may be transmitted together with the transmission data. Further, in the present invention, either the block brightness pattern detection or the average brightness value detection may be processed first, or these may be processed simultaneously.
Further, in the present invention, in detecting the rotation angle between the luminance pattern of the block and the reference luminance pattern, either the block side or the reference luminance pattern may be rotated, and the point is that the relative rotation between the two is performed. It is only necessary to be able to detect the angle. Further, in the present invention, either the brightness value correction or the rotation processing on the receiving device side may be processed first, or these may be processed simultaneously. Further, the present invention may be configured as a transmitter / receiver of image data, and each transmitter / receiver may be provided with both functions of the transmitter and the receiver shown in the above embodiments.

[0023]

As described above, according to the image data communication system of the present invention, the image data of the block to be transmitted is compressed by using the preset reference luminance pattern. It is possible to realize highly novel new image communication. In addition, since the size of the block that divides the image data is as small as possible in the part including the boundary line, it is possible to faithfully reproduce the original image at least in the boundary line part of the reproduced image, and high-speed communication with high compression degree is possible. It is possible to faithfully transmit image information while realizing the above.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an image data communication system according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a boundary detection process according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating block size determination processing according to an embodiment of the present invention.

FIG. 4 is a diagram illustrating a brightness distribution pattern detection process according to an embodiment of the present invention.

FIG. 5 is a conceptual diagram showing data in a compression process according to an embodiment of the present invention.

FIG. 6 is a conceptual diagram showing compressed data according to an embodiment of the present invention.

[Explanation of symbols]

10 ... Transmitting device, 12 ... Boundary detecting means, 13
... Block dividing means, 14 ... Compressing means, 1
5 ... Transmission means, 16 ... Size determination means, 17
... Position detecting means, 18 ... Luminance value detecting means, 1
9 ... Luminance pattern detecting means, 20 ... Rotation angle detecting means, 30 ... Receiving device, 31 ... Receiving means, 32 ... Expanding means, 33 ... Reconstructing means,
35 ... Correction means, 36 ... Rotation processing means,

Claims (1)

[Claims] 1. In an image data communication system for compressing image data divided into blocks composed of a plurality of pixels and transmitting the compressed image data from a transmission device to a reception device, the transmission device includes a boundary between images inputted from the input image data. A boundary detecting means for detecting a line, a block including the boundary line is a minimum size, a dividing means for dividing the input image data into a plurality of blocks, a position detecting means for detecting a position of each block in an image, Luminance value detecting means for detecting the average luminance value of each block, luminance pattern detecting means for detecting the luminance pattern of each block, and the reference luminance pattern and the luminance pattern of each block using a preset reference luminance pattern. And a rotation angle detecting means for detecting a rotation angle corresponding to, and a position of each block, an average brightness value and a rotation angle. A receiving unit that receives data of each block from the transmitting unit; and a receiving unit that receives the brightness value of the reference brightness pattern according to an average brightness value of each block data. Luminance value correcting means for correcting, rotation processing means for performing reverse rotation processing of each luminance value corrected reference luminance pattern according to the rotation angle of the corresponding block data, and each reference luminance subjected to luminance value correction and inverse rotation processing An image data communication system, comprising: a reconstructing unit that reconstructs a pattern according to the position of corresponding block data.