Image-data processing device, image-data processing method, image-data distributing device and image-data transmitting system
First Claim
1. An image-data processing device, in which an original image is divided into a plurality of blocks that are made up of a plurality of picture elements, and in each block, from encoded image-data which is obtained by encoding a spatial-frequency component of the block as a plurality of spatial-frequency coefficients, reduced encoded image-data is produced which is encoded data on a reduced image that is obtained by reducing the original image to a given reduction rate, comprising:
- a block abstracting means for abstracting each block as a block to be processed, one after another, from the plurality of blocks;
a DC-coefficient abstracting means for abstracting a direct-current component coefficient from the plurality of spatial-frequency coefficients of the block to be processed;
an adjacent DC-coefficient abstracting means for abstracting the direct-current component coefficient of at least one adjacent block which is adjacent, in any of a horizontal direction, a vertical direction and an oblique direction, to the block to be processed, as at least one adjacent direct-current component coefficient;
a DC-coefficient comparing means for comparing the direct-current component coefficient of the block to be processed and the at least one adjacent direct-current component coefficient, and calculating a value of a predetermined function of the direct-current component coefficient of the block to be processed and the at least one adjacent direct-current component coefficient, the function representing an extent of unevenness between the direct-current component coefficient of the block to be processed and the at least one adjacent direct-current component coefficient;
a coefficient-set setting means for, if the value of the function is larger than a predetermined value, holding a smaller number of spatial-frequency coefficients than the plurality of spatial-frequency coefficients of the block to be processed according to the reduction rate, which have lower frequencies and include the direct-current component coefficient among the plurality of spatial-frequency coefficients of the block to be processed, and setting the other spatial-frequency coefficients to zero; and
a DC-coefficient setting means for, if the value of the function is smaller than the predetermined value, holding only the direct-current component coefficient of the plurality of spatial-frequency coefficients of the block to be processed, and setting the other spatial-frequency coefficients to zero.
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Accused Products
Abstract
An original image is divided into a plurality of blocks that are made up of a plurality of picture elements, and in each block, from encoded image-data which is obtained by encoding a spatial-frequency component of the block as a plurality of spatial-frequency coefficients, reduced encoded image-data is produced which is encoded data on a reduced image that is obtained by reducing the original image to a given reduction rate. If the block in the encoded image-data of the original image is in an area where the value of the function is small due to gentle change in brightness or color of the image, for example, only the direct-current component coefficient of is used for the block. On the other hand, if the block is in a area where the value of the function is large because the area is a boundary area, for example, such as an outline in the image, limited number of lower spatial frequency-coefficients are used for the block. The number is based on the reduction rate of the image.
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Citations
28 Claims
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1. An image-data processing device, in which an original image is divided into a plurality of blocks that are made up of a plurality of picture elements, and in each block, from encoded image-data which is obtained by encoding a spatial-frequency component of the block as a plurality of spatial-frequency coefficients, reduced encoded image-data is produced which is encoded data on a reduced image that is obtained by reducing the original image to a given reduction rate, comprising:
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a block abstracting means for abstracting each block as a block to be processed, one after another, from the plurality of blocks;
a DC-coefficient abstracting means for abstracting a direct-current component coefficient from the plurality of spatial-frequency coefficients of the block to be processed;
an adjacent DC-coefficient abstracting means for abstracting the direct-current component coefficient of at least one adjacent block which is adjacent, in any of a horizontal direction, a vertical direction and an oblique direction, to the block to be processed, as at least one adjacent direct-current component coefficient;
a DC-coefficient comparing means for comparing the direct-current component coefficient of the block to be processed and the at least one adjacent direct-current component coefficient, and calculating a value of a predetermined function of the direct-current component coefficient of the block to be processed and the at least one adjacent direct-current component coefficient, the function representing an extent of unevenness between the direct-current component coefficient of the block to be processed and the at least one adjacent direct-current component coefficient;
a coefficient-set setting means for, if the value of the function is larger than a predetermined value, holding a smaller number of spatial-frequency coefficients than the plurality of spatial-frequency coefficients of the block to be processed according to the reduction rate, which have lower frequencies and include the direct-current component coefficient among the plurality of spatial-frequency coefficients of the block to be processed, and setting the other spatial-frequency coefficients to zero; and
a DC-coefficient setting means for, if the value of the function is smaller than the predetermined value, holding only the direct-current component coefficient of the plurality of spatial-frequency coefficients of the block to be processed, and setting the other spatial-frequency coefficients to zero. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An image-data processing method, in which an original image is divided into a plurality of blocks that are made up of a plurality of picture elements, and in each block, from encoded image-data which is obtained by encoding a spatial-frequency component of the block as a plurality of spatial-frequency coefficients, reduced encoded image-data is produced which is encoded data on a reduced image that is obtained by reducing the original image to a given reduction rate, comprising:
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a first step of abstracting a direct-current component coefficient from the plurality of spatial-frequency coefficients;
a second step of abstracting the direct-current component coefficient of at least one adjacent block which is adjacent, in any of a horizontal direction, a vertical direction and an oblique direction, to a block including the abstracted direct-current component coefficient, as at least one adjacent direct-current component coefficient;
a third step of comparing the direct-current component coefficient of and the at least one adjacent direct-current component coefficient, and calculating a value of a predetermined function of the direct-current component coefficient and the at least one adjacent direct-current component coefficient, the function representing an extent of unevenness between the direct-current component coefficient and the at least one adjacent direct-current component coefficient;
a fourth step of, if the value of the function is larger than a predetermined value, holding a smaller number of spatial-frequency coefficients than the plurality of spatial-frequency coefficients according to the reduction rate, which have lower frequencies and include the direct-current component coefficient among the plurality of spatial-frequency coefficients, and setting the other spatial-frequency coefficients to zero; and
a fifth step of, if the value of the function is smaller than the predetermined value, holding only the direct-current component coefficient of the plurality of spatial-frequency coefficients, and setting the other spatial-frequency coefficients to zero, wherein each step is executed on each block, so that the reduced encoded image-data is produced which is encoded data on a reduced image that is obtained by reducing the original image to the reduction rate. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. An image-data distributing device, in which an original image is divided into a plurality of blocks that are made up of a plurality of picture elements, in each block, from encoded image-data which is obtained by encoding a spatial-frequency component of the block as a plurality of spatial-frequency coefficients, reduced encoded image-data is produced which is encoded data on a reduced image that is obtained by reducing the original image to a given reduction rate, and the reduced encoded image-data is transmitted over a network, comprising:
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an encoded image-data storing means for storing a plurality of pieces of the encoded image-data;
an encoded image-data reading means for reading encoded image-data which corresponds to one image, from among the plurality of pieces of encoded image-data which is stored in the encoded image-data storing means; and
an image-data processing device, including;
a block abstracting means for abstracting each block as a block to be processed, one after another, from the plurality of blocks;
a DC-coefficient abstracting means for abstracting a direct-current component coefficient from the plurality of spatial-frequency coefficients of the block to be processed;
an adjacent DC-coefficient abstracting means for abstracting the direct-current component coefficient of at least one adjacent block which is adjacent, in any of a horizontal direction, a vertical direction and an oblique direction, to the block to be processed, as at least one adjacent direct-current component coefficient;
a DC-coefficient comparing means for comparing the direct-current component coefficient of the block to be processed and the at least one adjacent direct-current component coefficient, and calculating a value of a predetermined function of the direct-current component coefficient of the block to be processed and the at least one adjacent direct-current component coefficient, the function representing an extent of unevenness between the direct-current component coefficient of the block to be processed and the at least one adjacent direct-current component coefficient;
a coefficient-set setting means for, if the value of the function is larger than a predetermined value, holding a smaller number of spatial-frequency coefficients than the plurality of spatial-frequency coefficients of the block to be processed according to the reduction rate, which have lower frequencies and include the direct-current component coefficient among the plurality of spatial-frequency coefficients of the block to be processed, and setting the other spatial-frequency coefficients to zero; and
a DC-coefficient setting means for, if the value of the function is smaller than the predetermined value, holding only the direct-current component coefficient of the plurality of spatial-frequency coefficients of the block to be processed, and setting the other spatial-frequency coefficients to zero, wherein the image-data processing device produces the reduced encoded image-data, from encoded image-data which is read by the encoded image-data reading means, and the image-data distributing device further comprises a transmitting means for transmitting, to the network, the reduced encoded image-data which is produced by the image-data processing device.
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26. An image-data transmitting system, comprising an image-data distributing device, in which an original image is divided into a plurality of blocks that are made up of a plurality of picture elements, in each block, from encoded image-data which is obtained by encoding a spatial-frequency component of the block as a plurality of spatial-frequency coefficients, reduced encoded image-data is produced which is encoded data on a reduced image that is obtained by reducing the original image to a given reduction rate, and the reduced encoded image-data is transmitted over a network, including:
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an encoded image-data storing means for storing a plurality of pieces of the encoded image-data;
an encoded image-data reading means for reading encoded image-data which corresponds to one image, from among the plurality of pieces of encoded image-data which is stored in the encoded image-data storing means; and
an image-data processing device, in which an original image is divided into a plurality of blocks that are made up of a plurality of picture elements, and in each block, from encoded image-data which is obtained by encoding a spatial-frequency component of the block as a plurality of spatial-frequency coefficients, reduced encoded image-data is produced which is encoded data on a reduced image that is obtained by reducing the original image to a given reduction rate, having;
a block abstracting means for abstracting each block as a block to be processed, one after another, from the plurality of blocks;
a DC-coefficient abstracting means for abstracting a direct-current component coefficient from the plurality of spatial-frequency coefficients of the block to be processed;
an adjacent DC-coefficient abstracting means for abstracting the direct-current component coefficient of at least one adjacent block which is adjacent, in any of a horizontal direction, a vertical direction and an oblique direction, to the block to be processed, as at least one adjacent direct-current component coefficient;
a DC-coefficient comparing means for comparing the direct-current component coefficient of the block to be processed and the at least one adjacent direct-current component coefficient, and calculating a value of a predetermined function of the direct-current component coefficient of the block to be processed and the at least one adjacent direct-current component coefficient, the function representing an extent of unevenness between the direct-current component coefficient of the block to be processed and the at least one adjacent direct-current component coefficient;
a coefficient-set setting means for, if the value of the function is larger than a predetermined value, holding a smaller number of spatial-frequency coefficients than the plurality of spatial-frequency coefficients of the block to be processed according to the reduction rate, which have lower frequencies and include the direct-current component coefficient among the plurality of spatial-frequency coefficients of the block to be processed, and setting the other spatial-frequency coefficients to zero; and
a DC-coefficient setting means for, if the value of the function is smaller than the predetermined value, holding only the direct-current component coefficient of the plurality of spatial-frequency coefficients of the block to be processed, and setting the other spatial-frequency coefficients to zero, wherein the image-data processing device produces the reduced encoded image-data, from encoded image-data which is read by the encoded image-data reading means, the image-data distributing device further comprises a transmitting means for transmitting, to the network, the reduced encoded image-data which is produced by the image-data processing device, and the image-data transmitting system further comprises a terminal device which is connected over the network to the image-data distributing device, wherein the terminal device includes;
a reduced encoded image-data receiving means for receiving the reduced encoded image-data which is transmitted by the transmitting means;
a decoding means for decoding the reduced encoded image-data which is received;
an image-size reducing means for reducing an image size of the reduced encoded image-data which is decoded; and
a screen displaying means for displaying on a screen the reduced encoded image-data which is reduced in an image size. - View Dependent Claims (27, 28)
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Specification