Method and apparatus for encoding and decoding color images

Claim 2

An image encoding apparatus comprising: a) input means for inputting color image data representing a color image; b) first detection means for detecting an edge portion in the color image; c) second detection means for detecting a portion having a specific color; d) discrimination means for discriminating the edge portion having the specific color based on the detection result of said first and second detection means; e) first encoding means for encoding the edge portion of the specific color discriminated by said discrimination means by using a first encoding method; and f) second encoding means for encoding the color image data of at least a portion of the color image other than the edge portion of the specific color by using a second encoding method different from the first encoding method.

Claim 3

An apparatus according to claim 1, wherein said input means is an image reading device for scanning an original and converting original data into image data in units of pixels.

Claim 4

An apparatus according to claim 1, wherein said input means is a host computer.

Claim 5

An apparatus according to claim 1, wherein said first detection means detects whether a block contains an edge in each block constituted by a plurality of pixels.

Claim 6

An apparatus according to claim 1, wherein said first encoding means encodes a portion of the input image data which is discriminated as the edge portion of the specific color so as to increase a resolution in accordance with the first encoding method and said second encoding means encodes a remaining portion so as to increase gradation in accordance with the second encoding method different from the first encoding method.

Claim 7

An apparatus according to claim 5, wherein the first encoding method is an invertible encoding method.

Claim 8

An apparatus according to claim 5, wherein the second encoding method is an encoding method using orthogonal conversion.

Claim 9

An apparatus according to claim 7, wherein the orthogonal conversion is discrete cosine transform.

Claim 10

An apparatus according to claim 1, further comprising means for storing encoded data.

Claim 11

An apparatus according to claim 1, further comprising means for transmitting encoded data.

Claim 12

An image processing apparatus comprising: a) emphasizing means for emphasizing an edge of input image data; b) detection means for detecting a line image portion of a specific color of the input image data; c) encoding means for encoding the line image portion of the specific color detected by said detection means and a remaining image portion except for the line image portion of the specific color in accordance with different encoding methods; d) extraction means for extracting an achromatic portion around the line image portion of the specific color; and e) substitution means for substituting an image of an original portion corresponding to a pattern obtained by said extracting means with an average value of color components around the line image portion of the specific color.

Claim 13

An image processing apparatus comprising: a) emphasizing means for emphasizing an edge of input image data; b) detection means for detecting a line image portion of a specific color of the input image data; c) encoding means for encoding the line image portion of the specific color detected by said detection means and a remaining image portion except for the line image portion of the specific color in accordance with different encoding methods; d) extraction means for extracting an achromatic portion around the line image portion of the specific color; and e) substitution means for substituting an image of an original portion corresponding to a pattern obtained by said extracting means with an average value of color components around the line image portion of the specific color.

Claim 14

An image processing apparatus comprising: a) emphasizing means for emphasizing an edge of input color image data representing a color image; b) first detection means for detecting an edge portion in the color image based on the input image data of the edge emphasized by said emphasizing means; c) second detection means for detecting a portion having a specific color; d) discrimination means for discriminating the edge portion having the specific color based on the detection result of said first and second detection means; e) first encoding means for encoding the edge portion of the specific color discriminated by said discrimination means by using a first encoding method; and f) second encoding means for encoding the color image data of at least a portion of the color image other than the edge portion of the specific color by using a second encoding method different from the first encoding method.

Claim 15

An image processing apparatus comprising: a) emphasizing means for emphasizing an edge of input color image data representing a color image; b) first detection means for detecting an edge portion in the color image based on the input image data of the edge emphasized by said emphasizing means; c) second detection means for detecting a portion having a specific color; d) discrimination means for discriminating the edge portion having the specific color based on the detection result of said first and second detection means; e) first encoding means for encoding the edge portion of the specific color discriminated by said discrimination means by using a first encoding method; and f) second encoding means for encoding the color image data of at least a portion of the color image other than the edge portion of the specific color by using a second encoding method different from the first encoding method.

Claim 16

An apparatus according to claim 12, wherein said emphasizing means emphasizes an edge of an achromatic portion of the input image data.

Claim 17

An apparatus according to claim 12, wherein said first detection means detects whether a block contains an edge in each block constituted by a plurality of pixels.

Claim 18

An apparatus according to claim 12, further comprising means for extracting an achromatic portion around the line image portion of the specific color.

Claim 19

An apparatus according to claim 12, wherein said second encoding means performs encoding of a portion except for the edge portion of the specific color by using orthogonal conversion, and said first encoding means performs encoding of the edge portion of the specific color in accordance with another encoding method.

Claim 20

An apparatus according to claim 12, wherein said first encoding means encodes the edge portion of the specific color as binary pattern data and said second encoding means encodes a remaining portion as multivalue data.

Claim 21

An apparatus according to claim 12, wherein the specific color is black.

Claim 22

An image processing apparatus comprising: a) input means for inputting color image data representing a color image; b) first detecting means for detecting an edge portion in the color image; c) second detection means for detecting a portion having a specific color; d) discrimination means for discriminating the edge portion having the specific color based on the detection result of said first and second detection means; e) enlarging means for enlarging the edge portion of the specific color discriminated by said discrimination means; f) first encoding means for encoding the edge portion of the specific color enlarged by said enlarging means by using a first encoding method; and g) second encoding means for encoding the color image data of at least a portion of the color image other than the edge portion of the specific color enlarged by said enlarging means by using a second encoding method different from the first encoding method.

Claim 23

An image processing apparatus comprising: a) input means for inputting color image data representing a color image; b) first detecting means for detecting an edge portion in the color image; c) second detection means for detecting a portion having a specific color; d) discrimination means for discriminating the edge portion having the specific color based on the detection result of said first and second detection means; e) enlarging means for enlarging the edge portion of the specific color discriminated by said discrimination means; f) first encoding means for encoding the edge portion of the specific color enlarged by said enlarging means by using a first encoding method; and g) second encoding means for encoding the color image data of at least a portion of the color image other than the edge portion of the specific color enlarged by said enlarging means by using a second encoding method different from the first encoding method.

Claim 24

An apparatus according to claim 19, wherein said first detection means detects whether a block contains an edge in each block constituted by a plurality of pixels.

Claim 25

An apparatus according to claim 19, wherein said enlarging means enlarges the edge portion of the specific color in accordance with color component discrimination of pixels around an objective pixel.

Claim 26

An apparatus according to claim 19, further comprising means for substituting input an image data portion corresponding to a pattern obtained by said enlarging means with an average value of image data of pixels of the input image data.

Claim 27

An apparatus according to claim 19, wherein said second encoding means performs encoding of a portion except for the edge portion of the specific color by using orthogonal conversion, and said first encoding means performs encoding of the edge portion of the specific color in accordance with another encoding method.

Claim 28

An apparatus according to claim 19, wherein said first means encodes the edge portion of the specific color as binary pattern data and said second encoding means encodes a remaining portion as multivalue data.

Claim 29

An apparatus according to claim 19, wherein the specific color is black.

Claim 30

An image encoding apparatus comprising: a) input means for inputting color image data representing a color image; b) first detection means for detecting an edge portion in the color image; c) second detection means for detecting a portion having a plurality of specific colors; d) discrimination means for discriminating the edge portion having the plurality of specific colors based on the detection result of said first and second detection means; e) first encoding means for encoding the edge portion of the plurality of specific colors discriminated by said discrimination means by using a first encoding method; and f) second encoding means for encoding the color image data of at least a portion of the color image other than the edge portion of the plurality of specific colors by using a second encoding method different from the first encoding method.

Claim 31

An image encoding apparatus comprising: a) input means for inputting color image data representing a color image; b) first detection means for detecting an edge portion in the color image; c) second detection means for detecting a portion having a plurality of specific colors; d) discrimination means for discriminating the edge portion having the plurality of specific colors based on the detection result of said first and second detection means; e) first encoding means for encoding the edge portion of the plurality of specific colors discriminated by said discrimination means by using a first encoding method; and f) second encoding means for encoding the color image data of at least a portion of the color image other than the edge portion of the plurality of specific colors by using a second encoding method different from the first encoding method.

Claim 32

An apparatus according to claim 26, wherein said first detection means detects whether a block contains an edge in each block constituted by a plurality of pixels.

Claim 33

An apparatus according to claim 26, wherein said first encoding means encodes the line image portions after the line image portions are converted into binary series data.

Claim 34

An image processing apparatus comprising: first extracting means for extracting a line image portion having a predetermined color from a color image represented by input color image data; second extracting means for extracting an image portion around the line image portion having a color substantially similar to the predetermined color; and processing means for changing the input image date in the image portion extracted by said second extracting means.

Claim 35

An image processing apparatus comprising: first extracting means for extracting a line image portion having a predetermined color from a color image represented by input color image data; second extracting means for extracting an image portion around the line image portion having a color substantially similar to the predetermined color; and processing means for changing the input image date in the image portion extracted by said second extracting means.

Claim 36

An apparatus according to claim 29, wherein said processing means changes the image data portion extracted by said second extracting means into a value corresponding to an average color value of pixels around said extracted image portions.

Claim 37

An apparatus according to claim 29, further comprising means for encoding the line image portion of the predetermined color extracted by said first extracting means in accordance with a method different from that of a remaining image portion.