Image processing apparatus

• US 4,786,976 A
• Filed: 02/16/1984
• Issued: 11/22/1988
• Est. Priority Date: 02/25/1983
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Mikada, Hiroyuki, Takao, Mitsuji
• Primary Examiner(s): Coles, Sr., Edward L.
• Application Number:
  US06/580,821
• Time in Patent Office: 1,741 Days
• Field of Search: 358/280, 358/283, 358/282, 358/298, 353/53, 353/51
• US Class Current: 358/2.1
• CPC Class Codes: H04N 1/40062 Discrimination between different image types, e.g. two-tone, continuous tone
• CPC Class Codes: H04N 1/4055 producing a clustered dots or a size modulated halftone pattern

Abstract

An image processing apparatus comprises a memory for storing image data of each of a plurality of blocks of an input image data, a buffer for delaying the input image data and a processor for processing the image data supplied from the buffer in a processing manner determined by the output of the memory.

Claims

1. An image processing apparatus comprising:

input means for inputting pixel data;

discrimination means for discriminating whether the pixel data inputted by said input means represents a half-tone image or non-half-tone image for each of a plurality of blocks, each said block having a plurality of pixel data arranged in two dimensions;

buffer means for delaying the pixel data inputted by said input means; and

process means for processing the pixel data outputted from said buffer means for each said block, in accordance with the result of the discrimination performed by said discrimination means,

wherein said discrimination means performs the discrimination operation thereof in synchronism with input of the pixel data into said buffer means, and

wherein said discrimination means sequentially receives the pixel data, for each line, and determines whether said block represents half-tone or non-half-tone in synchronism with input of the pixel data corresponding to the last line of the block.

2. An image processing apparatus according to claim 1, wherein said discrimination means includes memory means for storing a predetermined value for each said block and discriminates whether said block represents a half-tone image or a non-half-tone image on a basis of the predetermined value.

3. An image processing apparatus according to claim 2, wherein said discrimination means includes setting means for comparing sequentially inputted pixel data of said block with the predetermined value relating to said block to set a new predetermined value and store the new predetermined value in said memory means in accordance with the comparison result.

4. An image processing apparatus according to claim 2, wherein the predetermined value is a maximum value or a minimum value of the pixel data in said block.

5. An image processing apparatus according to claim 4, wherein said memory means includes a first memory means and a second memory means for storing the maximum and minimum respectively, and wherein said discrimination means includes operating means for performing an operation on the maximum value and the minimum value and discriminates whether said block represents a half-tone image or a non-half-tone image in accordance with the result of the operation by said operation means.

6. An image processing aparatus according to claim 5, wherein said buffer means delays the pixel data inputted by said input means, corespondingly to the discriminating operation by said discrimination means.

7. An image processing apparatus according to claim 6, wherein said process means comprises dither process means for performing dither conversion of the pixel data by utilizing a predetermined threshold matrix and binarizing means for binarizing the pixel data by utilizing a fixed threshold, and selects one of said dither process means and said binarizing means in accordance with the result of the discrimination performed by said discrimination means.

8. An image processing apparatus comprising:

input means for inputting pixel data;

first memory means and second memory means for storing first and second predetermined values for each of a plurality of blocks, respectively, each said block having a plurality of pixel data;

selection means for selecting a processing manner for the pixel data in accordance with the first and second predetermined values stored in said first and second memory means;

buffer means for delaying the pixel data inputted by said input means; and

process means for processing the pixel data outputted from said buffer means in the manner determined by the output of said selection means;

said first and second memory means performing the storage operation thereof in synchronism with input of said first and second predetermined values into said buffer means, respectively; and

setting means for parallelly comparing sequentially inputted pixel data of each said block with said first and second predetermined values relating to said block to set new first and second predetermined values and storing the new first and second predetermined values in said first and second memory means, respectively in accordance with the comparison result.

9. An image processing apparatus according to claim 8, wherein said selection means includes parameter setting means for setting a parameter for selecting the process manner based on said first and second predetermined values and storing said parameter.

10. An image processing apparatus according to claim 8, wherein said first and second memory means store maximum and minimum values, respectively, of the pixel data of each said block.

11. An image processing apparatus according to claim 8, wherein said process means comprises dither process means for performing dither conversion of the pixel data by utilizing a predetermined threshold matrix and binarizing means for binarizing the pixel data by utilizing a fixed threshold, and selects one of said dither process means and said binarizing means in accordance with the output from said selection means.

12. An image processing apparatus according to claim 8, wherein said selection means discriminates whether the pixel data inputted by said input means represents a half-tone image or a non-half-tone image for each of said blocks on the basis of said first and second predetermined values, and said process means proceses the pixel data outputted from said buffer means for each block, in accordance with the output from said selection means.

13. An image processing apparatus comprising:

document read means for reading a document to produce pixel data;

discrimination means for discriminating half-tone and non-half-tone for each of a plurality of blocks arranged in main-scan direction of said document read means, each said lock having a plurality of pixel data arranged in two dimensions;

said discrimination means sequentially receiving the pixel data, for each line, from said document read means and determining whether said block represents half-tone or non-half-tone in synchronism with input of the pixel data corresponding to the last line of the block; and

output means for processiong the pixel data from said document read means in accordance with the discrimination result by said discrimination means and outputting an image signal.

14. An image processing apparatus according to claim 13, wherein said output means includes buffer means for delaying the pixel data supplied from said document read means and process means for processing the pixel data outputted from said buffer means in accordance with the result of the discrimination performed by said discrimination means.

15. An image processing apparatus according to claim 14, wherein said discrimination means includes memory means for storing a predetermined value for each block, and discriminates whether said block represents a half-tone image or a non-half-tone image on the basis of the predetermined value.

16. An image processing apparatus according to claim 15, wherein said discrimination means includes setting means for comparing the sequentially inputted pixel data of said block with the predetermined value relating to said block to set a new predetermined value and store the new predetermined value in said memory means in accordance with the comparison result.

17. An image processing apparatus according to claim 16, wherein the predetermined value is a maximum value or a minimum value of the pixel data in said block.

18. An image processing apparatus according to claim 14, wherein said buffer means delays the pixel data correspondingly to discrimination operation by said discrimination.

19. An image processing apparatus according to claim 18, wherein said process means comprises dither process means for performing dither conversion of the pixel data by utilizing a predetermined threshold matrix and binarizing means for binarizing the pixel data by utilizing a fixed threshold, and selects one of said dither process means and said binarizing means in accordance with the result of said discrimination means.

20. An image processing apparatus comprising:

a document to

document read means for reading produce pixel data;

discrimination means for discriminating half-tone and non-half-tone for each of a plurality of blocks arranged in a main-scan direction of said document read means, each said block having a plurality of pixel data; and

output means for processing the pixel data from said document read means in accordance with the output of said discrimination means and outputting an image signal before an end of document scan by said document read means,

wherein said output means includes buffer means for delaying the pixel data supplied from said document read means and process means for processing the pixel data outputted from said buffer means in accordance with the result of said discrimination means,

wherein said discrimination means includes memory means for storing a predetermined value for each block, and discriminates whether said block represents a half-tone image or a non-half-tone image on the basis of the predetermined value, and

wherein said discrimination means includes setting means for comparing sequentially inputted pixel data of said block with the predetermined value relating to said block to set a new predetermined value and store the new predetermined value in said memory means in accordance with the comparison result.

21. An image processing apparatus according to claim 20, wherein said discrimination means discriminates whether the pixel data inputted by said input means represents a half-tone image or a non-half-tone image for each of said blocks, and said process means processes the pixel data outputted from said buffer means for each block, in accordance with the result of said discrimination means.

22. An image processing apparatus according to claim 20, wherein the predetermined value is a maximum value or a minimum value of the pixel data in said block.

23. An image processing apparatus according to claim 20, wherein said buffer means delays the pixel data correspondingly to discrimination operation by said discrimination.

24. An image processing apparatus according to claim 23, wherein said process means comprises dither process means for performing dither conversion of the pixel data by utilizing a predetermined threshold matrix and binarizing means for binarizing the pixel data by utilizing a fixed threshold, and selects one of said dither process means and said binarizing means in accordance with the result of said discrimintion means.

25. An image processing apparatus comprising:

input means for inputting pixel data;

discrimination means for discriminating whether he pixel data inputted by said input means represents a half-tone image or a non-half-tone image on a basis of a predetermined value of the pixel data in one of a plurality of blocks, said block having a plurality of pixel data;

buffer means for delaying the pixel data inputted by said input means; and

process means for processing a pixel data outputted from said buffer means in accordance with the result of the discrimination performed by said discrimination means;

said discrimination means including memory means for storing the predetermined value of the pixel data in the lock and setting means for comparing sequentially inputted pixel data of said block with the predetermined value relating to said block to set a new predetermined value and store the new predetermined value in said memory means in accordance with the comparison result;

said discrimination means discriminating the pixel data in synchronism with input of the pixel data into said buffer means.

26. An image processing apparatus according to claim 25, wherein said memory means includes a first memory and a second memory for storing a first predetermined value and a second predetermined value of the pixel data in said block, respectively.

27. An image processing apparatus according to claim 26, wherein said discrimination means includes parameter setting means for setting a parameter on the basis of the first and second predetermined values stored in said first and second memories and for storing the parameter, said parameter determining a processing manner of said process means.

28. An image processing apparatus according to claim 27, wherein said process means comprises dither process means for performing dither conversion of the pixel data by utilizing a predetermined threshold matrix and binarizing means for binarizing the pixel data by utilizing a fixed threshold, and selects one of said dither process means and said binarizing means in accordance with the parameter.

29. An image processing apparatus according to claim 26, wherein said first and second memories store a maximum value and a minimum value of the pixel data in said block, respectively.