Image processing device

• US 5,353,132 A
• Filed: 06/22/1992
• Issued: 10/04/1994
• Est. Priority Date: 02/06/1989
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Katsuma, Makoto
• Primary Examiner(s): Coles, Sr., Edward L.
• Assistant Examiner(s): LEE, TOMMY D
• Application Number:
  US07/902,558
• Time in Patent Office: 834 Days
• Field of Search: 358/75, 358/78, 358/261.1, 358/261.2, 358/426, 358/430, 358/462, 358/467, 358/470, 358/500, 358/501, 358/538, 358/539, 382/56, 382/9, 364/715.02
• US Class Current: 358/539
• CPC Class Codes: G06T 2207/10008 from scanner, fax or copier
• CPC Class Codes: G06T 2207/30176 Document
• CPC Class Codes: G06T 7/90 Determination of colour characteristics
• CPC Class Codes: G06T 9/005 Statistical coding, e.g. Huffman, run length coding
• CPC Class Codes: H04N 1/41 Bandwidth or redundancy reduction by scanning H04N1/17 ; methods or arrangements for coding, decoding, compressing or decompressing digital video signals H04N19/00

Abstract

The type of color image is identified on the basis of a distribution of color information for each color. A plurality of different types of data compression algorithms prepared beforehand are changed according to the results of the identification. Preferably, the difference between the maximum value and the minimum value of each picture element of respective color separation data of a color image is determined, and further, a histogram of frequency of color information obtained for each color is determined. On the basis of the histogram, the type of the color image is identified by the fact that whether or not the histogram contains a peak greater than a predetermined value or whether or not the deviation of the histogram is greater than a predetermined value.

Claims

1. An image processing device comprising:

input means for inputting a plurality of color component signals representing a color image;

identification means for identifying a type of the color image on the basis of the plurality of color component signals from said input means;

first compression means for compressing the color component signals from said input means by using an information-preserving-type of encoding method;

second compression means for compressing the color component signals from said input means by using an information-non-preserving-type of encoding method;

selection means for selecting one of said first and second compression means in accordance with the type of the color image identified by said identification means; and

storage means for storing compressed color component signals from said first or second compression means together with identification data representing the type of the color image identified by said identification means.

2. An image processing device according claim 1, further comprising addition means for adding the identification data to the compressed color component signals.

3. An image processing device according to claim 2, wherein said storage means stores the compressed color component signals to which the identification data is added.

4. An image processing device according to claim 1, further comprising decompression means for decompressing the compressed color component signals stored in said storage means.

5. An image processing device according to claim 4, wherein said decompression means has a plurality of different types of decompression algorithms, and said decompression means decompresses the compressed color component signals by using a decompression algorithm which is selected in accordance with the identification data associated with the compressed color component signals.

6. An image processing device according to claim 1, wherein said identification means identifies the type of the color image on the basis of a histogram of frequency of the color component signals.

7. An image processing device according to claim 1, wherein said information-non-preserving-type of encoding method is a vector quantization method.

19. An image processing device according to claim 1, wherein said information-preserving-type of encoding method is a run length encoding method.

8. An image processing device comprising:

input means for inputting a plurality of color component signals representing a color image;

identification means for identifying a type of the color image on the basis of the plurality of color component signals from said input means;

first compression means for compressing the color component signals from said input means by using an information-preserving-type of encoding method;

second compression means for compressing the color component signals from said input means by using an information-non-preserving-type of encoding method;

selection means for selecting one of said first and second compression means in accordance with the type of the color image identified by said identification means;

storage means for storing compressed color component signals from said first or second compression means together with identification data representing the type of the color image identified by said identification means; and

decompression means for decompressing the compressed color component signals stored in said storage means in accordance with the identification data.

9. An image processing device according to claim 8, further comprising addition means for adding the identification data to the compressed color component signals.

10. An image processing device according to claim 9, wherein said storage means stores the compressed color component signals to which the identification data is added.

11. An image processing device according to claim 8, wherein said decompression means has a plurality of different types of decompression algorithms, and said decompression means decompresses the compressed color component signals by using any one of the decompression algorithm which is selected in accordance with the identification data associated with the compressed color component signals.

12. An image processing device according to claim 8, wherein said identification means identifies the type of the color image on the basis of a histogram of frequency of the color component signals.

13. An image processing device according to claim 8, wherein said information-preserving-type of encoding method is a run length encoding method.

14. An image processing device according to claim 8, wherein said information-non-preserving-type of encoding method is a vector quantization method.

15. An image processing method comprising the steps of:

inputting a plurality of color component signals representing a color image;

identifying a type of the color image on the basis of the plurality of color component signals;

selecting one of an information-preserving-type of encoding method and an information-non-preserving-type of encoding method in accordance with the type of the color image identified in said identifying step;

compressing the color component signals by using the selected encoding method; and

storing the compressed color component signals in a memory together with identification data representing the type of the color image identified in said identifying step.

16. An image processing method according to claim 15, wherein said information-preserving-type of encoding method is a run length encoding method.

17. An image processing method according to claim 15, wherein said information-non-preserving-type of encoding method is a vector quantization method.

18. An image processing method comprising the steps of:

inputting a plurality of color component signals representing a color image;

identifying a type of the color image on the basis of the plurality of color component signals;

selecting one of an information-preserving-type of encoding method and an information-non-preserving type of encoding method in accordance with the type of the color image identified by said identifying step;

compressing the color component signals by using the selected encoding method;

storing the compressed color component signals in a memory together with identification data representing the type of the color image identified by said identifying step; and

decompressing the compressed color component signals stored in said memory in accordance with the identification data.

20. An image processing method according to claim 18, wherein said information-preserving-type of encoding method is a run length encoding method.

21. An image processing method according to claim 18, wherein said information-non-preserving-type of encoding method is a vector quantization method.