Image processing apparatus

• US 4,595,956 A
• Filed: 08/14/1984
• Issued: 06/17/1986
• Est. Priority Date: 03/26/1981
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kawamura, Naoto, Masuda, Yukio
• Primary Examiner(s): Britton, Howard W.
• Application Number:
  US06/640,539
• Time in Patent Office: 672 Days
• Field of Search: 358/283, 358/298, 358/280, 358/81, 358/78
• US Class Current: 358/3.17
• CPC Class Codes: H04N 1/405 Halftoning, i.e. converting the picture signal of a continuous-tone original into a corresponding signal showing only two levels
• CPC Class Codes: H04N 1/4055 producing a clustered dots or a size modulated halftone pattern

Abstract

An image processing apparatus has an input section for converting input image information into a luminance signal, a memory to store the digitized luminance signal, a central processing unit for determining the matrix size for each picture element of the input image information so as to allow output of high space frequency components of input image information with matrices of small size and low space frequency components with matrices of large size, an outline emphasis circuit for emphasizing the outline when the image information is output with matrices of large size, and an output section for recording or displaying the input image information. Halftone images of excellent resolution and gradation can be output with a small memory capacity.

Claims

1. An image processing apparatus comprising:

input means for entering pixel data representing image density, a plurality of said pixel data defining a block and all of said pixel data defining a number of said blocks;

discrimination means for discriminating an image state in each said block in accordance with the difference between the image density of the respective pixel data within that block;

output means for outputting image patterns; and

determination means for determining an image pattern to be outputted by said output means and representing each said block on the basis of the result discrimination by said discrimination means.

2. An image processing apparatus according to claim 1, wherein said discrimination means and said determination means are incorporated in a common central processing unit.

3. An image processing apparatus according to claim 1, wherein said determination means determines that each image pattern outputted by said output means is composed of one of (1) one pixel datum, and (2) a plurality of pixel data defining one said block, on the basis of the result of discrimination by said discrimination means.

4. An image processing apparatus according to claim 1, wherein said determination means determines an image pattern to be outputted in accordance with the result of discrimination by said discrimination means and said pixel data in said block.

5. An image processing apparatus comprising:

input means for entering pixel data representative of image density; and

reproduction means for performing a half tone process on said pixel data in order to reproduce said pixel data as a half tone image, said reproduction means including output means for outputting an image pattern in accordance with said pixel data, and determination means for determining the size of said image pattern to be outputted by said output means in accordance with a plurality of said pixel data.

6. An image processing apparatus according to claim 5, wherein said reproduction means includes a central processing unit.

7. An image processing apparatus according to claim 5, wherein said determination means determines the size of said image pattern to be outputted in accordance with an image state in each block defined by a plurality of said pixel data.

8. An image processing apparatus according to claim 5, wherein said determination means includes discrimination means for discriminating an image state of a block comprising a plurality of the pixel data, said determination means determining the size of said image pattern to be outputted by said output means in accordance with the result of discrimination by said discrimination means.

9. An image processing apparatus according to claim 8, wherein said determination means determines that each said image pattern is composed of one of (1) one pixel datum, and (2) a plurality of pixel data, on the basis of the result of the discrimination by said discrimination means.

10. An image processing apparatus according to claim 8, wherein a plurality of pixel data define a block and all of said pixel data define a number of said blocks and wherein said discrimination means discriminates an image state in each said block in accordance with the difference between the density of the respective pixel data in that block.

11. An image processing apparatus comprising:

input means for entering pixel data representing image density; and

reproduction means for performing a half tone process on said pixel data to reproduce said pixel data as a half tone image, said reproduction means including switch means for switching modes for performance of said half tone process, one said mode including production of one image pattern unit from one pixel datum, said switch means being operable to switch said reproduction means from said one mode for performing a half tone process to another mode in which said reproduction means produces one image pattern unit from a plurality of pixel data.

12. An image processing apparatus according to claim 11, wherein a plurality of pixel data entered by said input means defined a block and all of said pixed data define a number of said blocks and wherein said apparatus further comprises discrimination means for discriminating an image state of the pixel data in each said block

13. An image processing apparatus according to claim 12, wherein said switch means switches said modes on the basis of the result of discrimination by said discrimination means.

14. An image processing apparatus according to claim 12, wherein said discrimination means discriminates an image state in each said block in accordance with the difference between the image density of the respective pixel data in that block.

15. An image processing apparatus comprising:

input means for entering pixel data representing image density, a plurality of two-dimensional pixel data entered by said input means defining a block and all of said pixel data defining a number of said blocks;

discrimination means for discriminating an image state in each said block; and

reproduction means for performing a half tone process for said plurality of pixed data in each said block to reproduce said pixed data as a half tone image, said reproduction means including switching means for switching modes for performance of said half tone process in accordance with the result of discrimination by said discrimination means, one said mode including production of one image pattern unit from said plurality of pixel data in one said block.

16. An image processing apparatus according to claim 15, wherein said switching means is operable to switch said reproduction means from said one mode for performing a half tone process to another mode in which said reproducing means produces one pattern unit from one pixel datum.

17. An image processing apparatus according to claim 15, wherein said switching means switches said modes on the basis of the result of discrimination by said discrimination means.

18. An image processing apparatus according to claim 15, wherein said discrimination means discriminates an image state in each said block in accordance with difference between the image density of the respective pixel data in that block.

19. An image processing apparatus comprising:

input means for entering digital pixel data representing image density, a plurality of tow-dimensional pixel data defining a block and all of said pixel data defining a number of said blocks; and

generation means for providing a binary signal representing said digital pixel data by performing a process for each said block, said generation means including discrimination means for discriminating an image state in each said block and for switching modes for performing said process for each said block in accordance with the result of discrimination by said discrimination means.

20. An image processing apparatus according to claim 19, wherein said generation means includes producing means for producing image patterns and wherein said generation means determines whether that each image pattern produced by said producing means is composed of one of (1) one pixel datum, and (2) a plurality of pixel data defining one said block, on the basis of the result of discrimination by said discrimination means.

21. An image processing apparatus according to claim 19, wherein said discrimination means discriminates an image state in each block in accordance with the difference in image density in the pixel data in that block.