Image processing apparatus capable of appriopriately encoding and processing entered image signals in accordance with the image content

• US 4,729,035 A
• Filed: 05/21/1984
• Issued: 03/01/1988
• Est. Priority Date: 06/01/1983
• Status: Expired due to Term

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Tanioka, Hiroshi
• Primary Examiner(s): Britton, Howard W.
• Assistant Examiner(s): Peng, John K.
• Application Number:
  US06/612,699
• Time in Patent Office: 1,380 Days
• Field of Search: 358/260, 358/262, 358/280, 358/282, 358/285, 358/288, 358/294, 358/284, 358/283
• US Class Current: 382/237
• CPC Class Codes: H04N 1/40062 Discrimination between different image types, e.g. two-tone, continuous tone

Abstract

An image processing apparatus capable of varying the method of binary encoding and processing in accordance with the content of the image, such as black-and-white image versus an image with intermediate tonal rendition. The image content is identified by detecting the maximum and minimum values of mutually neighboring plural pixels, and comparing the maximum value with a first reference value, the minimum value with a second reference value, and the difference between the maximum and minimum values with a third reference value.

Claims

1. An image processing apparatus comprising:

input means for entering image signals;

detecting means for detecting the maximum and minimum values of mutually neighboring plural pixels in the entered image signals;

first comparator means for comparing said maximum value with a first reference value;

second comparator means for comparing said minimum value with a second reference value;

third comparator means for detecting the difference between said maximum and minimum values and comparing said difference with a third reference value; and

means for discriminating as to whether or not an image represented by said neighboring plural pixels is an intermediate tone of image in accordance with the results of comparisons of said first, second and third comparator means.

2. An image processing apparatus according to claim 1, further comprising process means capable of applying mutually different image processes to the entered image signals, wherein said process means performs selectively a suitable image process in accordance with the result of discrimination of said discriminating means.

3. An image processing apparatus according to claim 1, wherein said input means comprises read-means for photoelectrically reading an original image.

4. An image processing apparatus according to claim 2, wherein said process means comprises binary encoding means capable of applying different binary encoding processes to the entered image signals, wherein said binary encoding means performs selectively a suitable binary encoding process in accordance with the result of discrimination of said discriminating means.

5. An image processing apparatus according to claim 4, wherein said binary encoding means is adapted to effect a first binary encoding process for intermediate tone reproduction and a second binary encoding process for linetone reproduction.

6. An image processing apparatus according to claim 4, further comprising compression means for compressing image signals which are binary encoded by said binary encoding means.

7. An image processing apparatus comprising:

input means for entering image signals;

first discriminating means for discriminating as to whether or not an image represented by the entered image signals is an intermediate tone of image;

second discriminating means for discriminating as to whether or not the image represented by the image signals is the intermediate tone of image with a method different from that of said first discriminating means; and

binary encoding means capable of applying different binary encoding processes to the entered image signals, said binary encoding means performing selectively a suitable binary encoding process in accordance with the result of discrimination of either said first or said second discriminating means,

wherein said binary encoding means employs the result of discrimination of either discriminating means according to the destination of the binary encoded image signals.

8. An image processing apparatus according to claim 7, wherein said binary encoding means is capable of a first binary encoding process for intermediate tone reproduction and a second binary encoding process for linetone reproduction, and selectively effects either said first or said second process in accordance with the result of discrimination of either said first or said second discriminating means.

9. An image processing apparatus according to claim 7, wherein the image signals binary encoded by said binary encoding means are transmitted to either first processing means for compressing the image signals or second processing means without such compression.

10. An image processing apparatus according to claim 7, wherein said input means comprises reading means for photoelectrically reading an original image.

11. An image processing apparatus according to claim 7, wherein each of said first and second discriminating means is operable to discriminate, on such a division basis that the entered image signals are divided into a plurality of blocks each comprising a predetermined number of image signals, as to whether or not each of the blocks is an intermediate tone of image.

12. An image signal processing apparatus comprising:

input means for entering image signals;

detecting means for detecting the maximum and minimum values of mutually neighboring plural pixels of the entered image signals;

first identifying means for detecting the difference of said maximum and minimum values and identifying whether said difference is within a first determined range;

second identifying means for identifying whether at least one of said maximum and minimum values is within a second determined range; and

discriminating means for discriminating as to whether or not an image represented by said neighboring plural pixels is an intermediate tone of image in accordance with the results of identification of said first and second identifying means.

13. An image signal processing apparatus according to claim 12, further comprising process means capable of applying mutually different image processes to the entered image signals, wherein said process means performs selectively a suitable image process in accordance with the result of discrimination of said discriminating means.

14. An image signal processing apparatus according to claim 12, wherein said input means comprises reading means for photoelectrically reading an original image.

15. An image signal processing apparatus according to claim 13, wherein said process means comprises binary encoding means capable of applying different binary encoding processes to the entered image signals, wherein said binary encoding means performs selectively a suitable binary encoding process in accordance with the result of discrimination of said discriminating means.

16. An image signal processing apparatus according to claim 15, wherein said binary encoding means is adapted to effect a first binary encoding process for intermediate tone reproduction and a second binary encoding process for linetone reproduction.

17. An image signal processing apparatus according to claim 15, further comprising compressing means for compressing the image signals which are binary encoded by said binary encoding means.

18. An image processing apparatus comprising:

input means for entering image signals;

first discriminating means for discriminating as to whether or not an image represented by the entered image signals is an intermediate tone of image;

second discriminating means for discriminating as to whether or not an image represented by the entered image signals is an intermediate tone of image, with a method different from that of said first discriminating means; and

process means capable of applying different image processes to the entered image signals, said process means performing selectively a suitable image process in accordance with the result of discrimination of either said first or said second discriminating means,

wherein said process means employs the result of discrimination of either of said discriminating means according to the destination of the processed image signals.

19. An image processing apparatus according to claim 18, wherein said process means comprises binary encoding means capable of applying different binary encoding processes to the entered image signals, and wherein said binary encoding means performs the suitable image process in accordance with the result of discrimination of either said first or said second discriminating means.

20. An image processing apparatus according to claim 19, wherein said binary encoding means is capable of a first binary encoding process for intermediate tone reproduction and a second binary encoding process for linetone reproduction, and selectively effects either said first or said second process in accordance with the result of discrimination of either said first or said second discriminating means.

21. An image processing apparatus according to claim 18, wherein the image signals binary encoded by said binary encoding means are transmitted to either of first processing means for compressing the image signals or second process means without such compression.

22. An image processing apparatus according to claim 18, wherein said input means comprises reading means photoelectrically reading an original image.

23. An image processing apparatus according to claim 18, wherein each of said first and second discriminating means is operable to discriminate, on such a division basis that the entered image signals are divided into a plurality of blocks each comprising a predetermined number of image signals, as to whether or not each of the blocks is an intermediate tone of image.