Monochromatic representation of color images

• US 4,688,031 A
• Filed: 03/30/1984
• Issued: 08/18/1987
• Est. Priority Date: 03/30/1984
• Status: Expired due to Term

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: Wang Laboratories Incorporated
• Inventors: Haggerty, William T.
• Primary Examiner(s): Curtis, Marshall M.
• Application Number:
  US06/595,027
• Time in Patent Office: 1,236 Days
• Field of Search: 340/703, 340/793, 340/730, 358/22, 358/81, 358/283, 358/298, 350/162.12
• US Class Current: 345/600
• CPC Class Codes: G06K 15/00 Arrangements for producing a permanent visual presentation of the output data , e.g. computer output printersprinting or plotting combined with another operation, e.g. with conveying, G06K17/00
• CPC Class Codes: G06K 15/02 using printers
• CPC Class Codes: G06K 2215/0094 Colour printing
• CPC Class Codes: G09G 3/2051 with use of a spatial dither pattern
• CPC Class Codes: G09G 5/028 Circuits for converting colour display signals into monochrome display signals
• CPC Class Codes: H04N 1/40012 Conversion of colour to monochrome

Abstract

A color to monochromatic image transformation which transforms each color area of the original image into a corresponding area of a monochromatic image having a particular pattern of `light` and `dark` dots corresponding to and representing the original color of the area. The dot patterns are selected to provide both gray scale representations of the original colors and differing textural appearances for each color, so as to maximize the discrimination between the areas of the monochromatic image. The monochromatic dot patterns do not necessarily correspond exactly to the colors or gray scale values of the original colors, but are selected to provide visual impressions analogous to the visual impressions provided by the corresponding original colors.

A further feature of the dot arrays selected to represent various colors is that the patterns of dots are selected for each array so as to avoid the creation of artifacts, that is, the formation of accidental or incidental patterns and figures within a given array or at the junction or border between two arrays.

A yet further feature is the enhancement, during transformation, of the visual appearance of alphanumeric characters and symbols. The original background color of the character or symbol is transformed into a monochromatic color pattern mask dot pattern as previously described. The original character or symbol foreground color field, that is, the character or symbol itself, however, is either transformed into a dark (black) field if the background color was `light` or into a light (white) field if the background color was `dark`. In the latter case, the original foreground field is effectively discarded and the character or symbol appears as a light `hole` in the `dark` background field.

Claims

1. A method for transforming a color image into a monochromatic image, the color image being comprised of a plurality of areas each having a color, comprising the steps of:

(A) providing a plurality of color pattern masks, each color pattern mask being associated with a color, and each color pattern mask representing a dot pattern comprised of a rectangular array of light and dark dots as follows

(1) in a mask for the color black

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000,

(2) in a mask for the color red

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 1011 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 1110,

(3) in a mask for the color green

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 1100 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0011,

(4) in a mask for the color yellow

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 1100 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000,

(5) in a mask for the color blue

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 1111 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 1111,

(6) in a mask for the color magenta

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 1010 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0101,

(7) in a mask for the color cyan

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 1010 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0001, and

(8) in a mask for the color white

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 1010 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000,

and for each area of the color image

(B) generating a character mask representing the area, and

(C) combining the character mask and the color pattern mask associated with the color of the area so as to replace each colored area with the dot pattern associated with the color of the area.

2. The method of claim 1, wherein the patterns for the even numbered rows are aligned with the patterns for the odd numbered rows such that the first dot of the odd row dot patterns are aligned with the first dot of the even row dot patterns except as follows:

(a) in the masks for yellow and cyan, the dot patterns in half of the even numbered rows are shifted two dot positions with the respect to the dot patterns in the other half of the even numbered rows, and

(b) in the mask for white, the dot patterns in half of the even numbered rows are shifted one dot positions with respect to the dot patterns in the other half of the even numbered rows.

3. A method for transforming a color image into a monochromatic image, the color image being comprised of a plurality of areas each having a color, comprising the steps of:

(A) providing a plurality of color pattern masks, each color pattern mask being associated with a color, and each color pattern mask representing a dot pattern comprised of a rectangular array of light and dark dots as follows

(1) in a mask for the color black

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000,

(2) in a mask for the color red

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 1011 and

ii. the odd numbered rows of the array are comprised of one of more repetitions of the dot pattern 1110,

(3) in a mask for the color green

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 11001100110011011100 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0011,

(4) in a mask for the color yellow

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 1001 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000,

(5) in a mask for the color blue

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 1111 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 1111,

(6) in a mask for color magenta

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 1011 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0100,

(7) in a mask for the color cyan

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 10001 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 00100 and

(8) in a mask for the color white

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 1000 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000,

and for each area of the color image

(B) generating a character mask representing the area, and

(C) combining the character mask and the color pattern mask associated with the color of the area so as to replace each colored area with the dot pattern associated with the color of the area.

4. The method of claim 3, wherein the patterns for the even numbered rows are aligned with the patterns for the odd numbered rows such that the first dot of the odd row dot patterns are aligned with the first dot of the even row dot patterns except as follows:

in the masks for yellow and white, the dot patterns in half of the even numbered rows are shifted two dot positions with respect to the dot patterns in the other half of the even numbered rows.

5. Means for transforming a color image into a monochromatic image, the color image being comprised of a plurality of areas each having a color, comprising:

(A) a plurality of color pattern masks, each color pattern mask being associated with a color, and each color pattern mask representing a dot pattern comprised of a rectangular array of light and dark dots as follows

(1) in a mask for the color black

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000,

(2) in a mask for the color red

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 1011 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 1110,

(3) in a mask for the color green

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 1100 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0011,

(4) in a mask for the color yellow

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 1100 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000,

(5) in a mask for the color blue

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 1111 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 1111,

(6) in a mask for the color magenta

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 1010 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0101,

(7) in a mask for the color cyan

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 1010 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0001, and

(8) in a mask for the color white

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 1010 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000,

(B) means for generating a character mask representing one of the colored areas of the color image, and

(C) means for combining the character mask and the color pattern mask associated with the color of the area represented by the character mask so as to replace the colored area with the dot pattern associated with the color of that area.

6. The means of claim 5, wherein the patterns for the even numbered rows are aligned with the patterns for the odd numbered rows such that the first dot of the odd row patterns are aligned with the first dot of the even row dot patterns except as follows:

(a) in the masks for yellow and cyan, the dot patterns in half of the even numbered rows are shifted two dot positions with respect to the dot patterns in the other half of the even numbered rows, and

(b) in the mask for white, the dot patterns in half of the even numbered rows are shifted one dot position with respect to the dot patterns in the other half of the even numbered rows.

7. Means for transforming a color image into a monochromatic image, the color image being comprised of a plurality of areas each having a color, comprising:

(A) a plurality of color pattern masks, each color pattern mask being associated with a color, and each color pattern mask representing a dot pattern comprised of a rectangular array of light and dark dots as follows

(1) in a mask for the color black

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000,

(2) in a mask for the color red

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 1011 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 1110,

(3) in a mask for the color green

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 11001100110011011100 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0011,

(4) in a mask for the color yellow

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 1001 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000,

(5) in a mask for the color blue

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 1111 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 1111,

(6) in a mask for the color magenta

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 1011 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0100,

(7) in a mask for the color cyan

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 10001 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 00100 and

(8) in a mask for the color white

i. the even numbered rows of the array are comprised of one or more repetitions of the dot pattern 1000 and

ii. the odd numbered rows of the array are comprised of one or more repetitions of the dot pattern 0000,

(B) means for generating a character mask representing one of the colored areas of the color image, and

(C) means for combining the character mask and the color pattern mask associated with the color of the area represented by the character mask so as to replace the color area with the dot pattern associated with the color of that area.

8. The means of claim 7, wherein the patterns for the even numbered rows are aligned with the patterns for the odd numbered rows such that the first dot of the odd row dot patterns are aligned with the first dot of the even row dot patterns except as follows:

in the masks for yellow and white, the dot patterns in half of the even numbered rows are shifted two dot positions with respect to the dot patterns in the other half of the even numbered rows.