Monochromatic representation of color images

Claim 2

Method for transforming a color image into a monochromatic image, characterized by the steps of: providing a plurality of color masks, each color mask corresponding to a color in the original image and comprised of a pattern of light and dark dots, wherein each pattern is selected, in relation to all other patterns, to provide gray scale and textural visual impressions providing discrimination between areas of the monochromatic image in a manner analogous to the corresponding original image colors, and replacing the color in each area of the color image with the corresponding color pattern mask dot pattern.

Claim 3

Method according to claim 1, characterized in that the dot patterns of the color pattern masks are selected to .avoid the creation of artifacts within a given dot pattern or at the junction between two dot patterns.

Claim 4

Method according to claim 1, characterized in that each color pattern mask is comprised of a rectangular array of dots and wherein in the mask for the color black, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 0000, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000, in the mask for the color red, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1011, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 1110, in the mask for the color green, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1100, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0011, in the mask for the color yellow, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1100, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000, in the mask for the color blue, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1111, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 1111, in the mask for the color magenta, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1010, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0101, in the mask for the color cyan, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1010, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0001, and in the mask for the color white, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1010, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000.

Claim 5

Method according to claim 1 or 2, characterized in that the first row of each color pattern mask is the Oth row, and in the masks for the colors yellow and white, the dot patterns for the second row and every forth row thereafter are complemented, and in the color pattern mask for the color cyan, the third row and every fourth row thereafter are comprised of one or more repetitions of the dot pattern 0100.

Claim 6

Method according to claim 1 or 2, characterized in that each color mask is comprised of a rectangular array of bits and that in the mask for the color black, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 0000, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000, in the mask for the color red, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1011, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 1110, in the mask for the color green, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1100, 1100, 1100, 1101 and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0011, in the mask for the color yellow, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1001, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000, in the mask for the color blue, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1111, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 1111, in the mask for the color magenta, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1011, and the odd numbered rows of the array are comprised of one or more repatitions of the dot pattern 0100, in the mask for the color cyan, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1000, 1100, 0110, 0011, 0001, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0010, 0001, 0000, 1000, 0100, and in the mask for the color white, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1000, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000.

Claim 7

Method according to claim 4, characterized in that the first row of each color pattern mask is the Oth row, and in the mask for the color yellow, the second row and every fourth row thereafter is comprised of one or more repetitions of the dot pattern 0110, and in the mask for the color white, the second row and every fourth row thereafter is comprised of one or more repetitions of the dot pattern 0010.

Claim 8

Method according to claim 1 or 2, characterized by enhancing alphanumeric characters appearing in the color image comprising the steps of: for each such character, replacing the color in the background area of each character with the corresponding color pattern mask dot pattern, and if the corresponding background color mask dot pattern (114) is a light mask, replacing the color area of the character with a solid pattern of dark dots, and if the corresponding background color pattern mask dot pattern is a dark pattern, replacing the color area of the character with a solid pattern of light dots.

Claim 9

Method according to claim 1 or 6, characterized in that for a dark background color the step of replacing the color area of the character with a solid pattern of light dots is comprised of the step of: deleting the area of the image comprising the character, so that the character appears as a hole containing no dot pattern in the dot pattern of the character background area.

Claim 10

Method according to claim 1 or 2, wherein the step of replacing the color in each area of the color image with the corresponding color pattern mask dot pattern is comprised of the steps of: for each color area, generating a character mask defining the color area in the image, selecting the corresponding color pattern mask, and generating a halftone field corresponding to the color area by logically ANDing the character mask and the corresponding color pattern mask and generating the final halftone image by logically ORing the halftone fields corresponding to the color areas.

Claim 11

Method according to claim 1 or 2, wherein the color image is comprised of character set graphics, each character of which contains a foreground field and a background field, characterized in that the step of replacing the color in each area of the color image with the corresponding color mask bit pattern is further comprised of the steps of: for each character of the image, generating a foreground character mask comprised of the foreground field of the character, generating a background character mask comprised of the background field of the character, selecting a foreground color pattern mask corresponding to the color of the foreground field, selecting a background color pattern mask corresponding to the color of the background field, generating a halftone foreground field by logically ANDing the foreground character mask and the foreground color pattern mask, generating a halftone background field by logically ANDing the background character mask and the background pattern color mask, and generating a final halftone font character by logically ORing the halftone foreground field and the halftone background field.

Claim 12

Method according to claim 1 or 2, wherein the color image is comprised of character set graphics, each character of which contains a foreground field and a background field, characterized by enhancing alphanumeric characters appearing in the color image wherein. the alphanumeric character comprises the foreground field of the character graphic, comprised of the steps of: for each alphanumeric character of the image, generating a foreground character mask comprised of the foreground field of the character, generating a background character mask comprised of the background field of the character, selecting a background color pattern mask corresponding to the color of the background field, generating a halftone background field by logically ANDing the background character mask and the background pattern color mask, and generating a halftone foreground field by the steps of, if the background color mask is a light mask, filling the foreground character mask with a solid pattern of dark dots, and if the background color mask is a dark mask, deleting the foreground character mask, and generating a final halftone font character by logically ORing the halftone foreground field and the halftone background field.

Claim 13

Method according to claim 10 or 11, characterized in that the steps of generating a background character mask is comprised of the step of complementing the foreground character mask.

Claim 14

Method according to claim 1, 6 or 11, characterized in that the light color pattern masks include the masks for the colors black, yellow, cyan and white.

Claim 15

Apparatus for transforming a color image (82) into a monochromatic image comprising: means (16,50,52) for providing a plurality of color masks, each color mask corresponding to a color in the original image (82) and comprised of a pattern of light and dark dots, wherein each pattern is selected, in relation to all other patterns, to provide gray scale and textural visual impressions providing discrimination between areas of the monochromatic image in a manner analogous to the corresponding original image colors, and means (16,50,52) for providing a color image (82), means (16,50,52) for replacing the color in each area (86, 84) of the color image (82) with the corresponding color mask dot pattern (92,94).

Claim 16

Apparatus for transforming a color image (82) into a monochromatic image comprising: means (16,50,52) for providing a plurality of color masks, each color mask corresponding to a color in the original image (82) and comprised of a pattern of light and dark dots, wherein each pattern is selected, in relation to all other patterns, to provide gray scale and textural visual impressions providing discrimination between areas of the monochromatic image in a manner analogous to the corresponding original image colors, and means (16,50,52) for providing a color image (82), means (16,50,52) for replacing the color in each area (86, 84) of the color image (82) with the corresponding color mask dot pattern (92,94).

Claim 17

Apparatus according to claim 14, characterized in that the dot patterns of the color pattern masks are selected to avoid the creation of artifacts within a given dot pattern or at the junction between two dot patterns.

Claim 18

Apparatus according to claim 14, characterized in that each color pattern mask is comprised of a rectangular array of dots and wherein in the mask for the color black, the even numbered rows of the array are comprised of one mor repetitions of the dot pattern 0000, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000, in the mask for the color red, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1011, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 1110, in the mask for the color green, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1100, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0011, in the mask for the color yellow, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1100, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000, in the mask for the color blue, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1111, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 1111, in the mask for the color magenta, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1010, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0101, in the mask for the color cyan, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1010, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0001, and in the mask for the color white, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1010, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000.

Claim 19

Apparatus according to claim 14 or 15, characterized in that the first row of each color pattern mask is the Oth row, and in the masks for the colors yellow and white, the dot patterns for the second row and every forth row thereafter are complemented, and in the mask for the color cyan, the third row and every fourth row thereafter are comprised of one or more repetitions of the dot pattern 0100.

Claim 20

Apparatus according to claim 14 or 15, characterized in that each color mask is comprised of a rectangular array of bits and that in the mask for the color black, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 0000, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000, in the mask for the color red, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1011, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 1110, in the mask for the color green, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1100, 1100, 1100, 1101 and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0011, in the mask for the color yellow, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1001, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000, in the mask for the color blue, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1111, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 1111, in the mask for the color magenta, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1011, and the odd numbered rows of the array are comprised of one or more repatitions of the dot pattern 0100, in the mask for the color cyan, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1000, 1100, 0110, 0011, 0001, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0010, 0001, 0000, 1000, 0100, and in the mask for the color white, the even numbered rows of the array are comprised of one more repetitions of the dot pattern 1000, and the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000.

Claim 21

Apparatus according to claim 18, characterized in that the first row of each mask is the Oth row, and in the mask for the color yellow, the second row and every fourth row thereafter is comprised of one.or more repetitions of the dot pattern 0110, and in the mask for the color white, the second row and every fourth row thereafter is comprised of one or more repetitions of the dot pattern 0010.

Claim 22

Apparatus according to claim 14 or 15, characterized by means (16,50,52) for enhancing alphanumeric characters appearing in the color image (102) comprising: means (16,50,52) for replacing the color in the back- ground area (106) of each character (104) with the corresponding color mask dot pattern (114) and means (16,50,52) responsive to the color of the back- ground area (106) of each character (104) for replacing the color area of the character (104) with a dot pattern, by if the corresponding background color mask dot pattern (114) is a light mask, replacing the color area of the character (104) with a solid pattern of dark dots, and if the corresponding background color mask dot pattern (114) is a dark mask, replacing the color area of the character (104) with a solid pattern of light dots.

Claim 23

Apparatus according to claim 14 or 20, characterized in that for a dark background color the means (16,50,52) responsive the color of the character background area (106) is responsive to a dark background mask by: deleting the area of the image (102) comprising the character (104), so that the character (104) appears as a hole containing no dot pattern in the dod pattern of the character background area (106).

Claim 24

Apparatus according to claim 14 or 15 , characterized in that the means (16,50,52) for replacing the color in each area (86,84) of the color image (82) with the corresponding color pattern mask dot pattern (92, 94) is further comprised of: means (16,50,52) for generating a character mask (88,90) defining the color area (86,84) in the image (82), means (16,50,52) for selecting the corresponding color pattern mask (92,94), and means (16,50,52) for generating a halftone field (96,98) corresponding to the color area (86,84) by logically ANDing the character mask (88,90) and the corresponding color pattern mask (92,94), and means (16,50,52) for generating the final halftone image (100) by logically ORing the halftone fields (96,98) corresponding to the color areas (86,84).

Claim 25

Apparatus according to claim 14 or 15, wherein the color image (82) is comprised of character set graphics, each character of which contains a foreground field (86) and a background field, characterized in that the means (16,50,52) for replacing the color in each area (86,84) of the color image (82) with the corresponding color mask bit pattern (92,94) is further comprised of: means (16,50,52) for generating a foreground character mask (88) comprised of the foreground field (86) of the character, means (16,50,52) for generating a background character mask (90) comprised of the background field (84) of the character (82), means (16,50,52) for selecting a foreground color pattern mask (92) corresponding to the color of the foreground field (86), means (16,50,52) for selecting a background color pattern mask (94) corresponding to the color of the background field (84), means (16,50,52) for generating a halftone foreground field (96) by logically ANDing the foreground character mask (88) and the foreground color pattern mask (92), means (16,50,52) for generating a halftone back- ground field (98) by logically ANDing the background character mask (90) and the background color pattern mask (94), and means (16,50,52) for generating a final halftone font character (100) by logically ORing the halftone foreground field (96) and the halftone background field (98).

Claim 26

The means of claim 14 or 15, wherein the color image (82) is comprised of character set graphics, each character of which contains a foreground field (86) and a background field (84), further comprising means (16,50,52) for enhancing alphanumeric characters appearing in the color image (102) wherein the alphanumeric character (104) appears as a foreground color (104) in the character graphic (102), comprised of: means (16,50,52) responsive to the color pattern mask (114) corresponding to the background field (106) of the character (102) for generating a halftone foreground field (112) by the steps of, by if the background color pattern mask (114) is a light mask, filling the foreground character mask (108) with a solid pattern of dard dots, and if the background color pattern mask (114) is a dark mask, deleting the foreground character mask (108).

Claim 27

Apparatus according to claim 23 or 24, characterized in that means (16,50,52) for generating a background character mask (110) is comprised of means (16,50,52) for complementing the foreground character mask (108).

Claim 28

Apparatus according to claim 14, 19 or 23, characterized in that the light color pattern masks include the masks for the-colors black, yellow, cyan and white. 1029