Image processing method and apparatus suitable for both high-resolution and low-resolution image data

• US 5,781,666 A
• Filed: 01/31/1995
• Issued: 07/14/1998
• Est. Priority Date: 04/17/1990
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Yamanashi, Yoshitsugu, Nonoshita, Hiroshi, Ishizawa, Yasuhisa, Chyo, Kenjiro
• Primary Examiner(s): JOHNS, ANDREW W
• Application Number:
  US08/380,940
• Time in Patent Office: 1,260 Days
• Field of Search: 358/450, 358/451, 358/452, 358/453, 358/528, 358/537, 358/538, 358/540, 395/102, 395/128, 395/117, 395/135
• US Class Current: 382/284
• CPC Class Codes: G06T 1/20 Processor architectures; Processor configuration, e.g. pipelining
• CPC Class Codes: H04N 1/3871 the composed originals being of different kinds, e.g. low- and high-resolution originals
• CPC Class Codes: H04N 1/40068 Modification of image resolution, i.e. determining the values of picture elements at new relative positions H04N1/3935 takes precedence

Abstract

An image processing apparatus makes it possible to efficiently use memories, and to output an image having a high picture quality and a high resolution. The apparatus also makes it possible to reproduce particularly edge portions of an image having a relatively low resolution wherein a plurality of bits are allocated per picture element, with a high resolution. The apparatus further makes it possible to reproduce an image having a high resolution represented by one bit per picture element as an image represented by a plurality of bits per picture element. The apparatus processes a color image obtained by synthesizing a photograph and another photograph, or a photograph and characters with a small memory capacity, and outputs an image having a high quality. That is, the apparatus comprises a memory for storing character/figure images having a high resolution and a small amount of information for one picture element, a memory for storing photographic images having a low resolution and a large amount of information per picture element, and a memory for storing control data for controlling the above-described two kinds of images. An image output having a high picture quality can be obtained with a small amount of information by effectively utilizing features of the above-described two kinds of images. It is thereby possible to reduce the number of devices required for storing information, and therefore to reduce cost. It is also possible to minimize deterioration in picture quality caused by reducing the amount of information.

Claims

1. An image data processing apparatus comprising:

first storage means for storing image data as contour data of a first resolution;

second storage means for storing the image data as color data of a resolution lower than the first resolution, the color data corresponding to a plurality of the contour data;

reading out means for reading a first number of data which are adjacent to each other of the contour data stored in said first storage means and a second number of data which are adjacent to each other of the color data including the color data corresponding to the plurality of the contour data stored in said second storage means;

selection means for selecting one color data from among the read second number of the color data at the position of each of the read first number of the contour data; and

generating means for generating a value of an area surrounded by the contour data by repeating reading out of data by said reading out means and selection of data by said selection means.

2. An image data processing apparatus according to claim 1, wherein the contour data comprises picture element data in which one picture element corresponds to one bit, and wherein the color data comprises picture element data in which one picture element corresponds to a plurality of bits.

3. An image data processing apparatus according to claim 2, further comprising an output device which outputs the image generated by said generation means.

4. An image data processing apparatus according to claim 3, wherein said output device outputs the image at a resolution which is the same as the first resolution.

5. An image data processing apparatus according to claim 1, further comprising an output device which outputs the image generated by said generation means.

6. An image data processing apparatus according to claim 5, wherein said output device outputs the image at a resolution which is the same as the first resolution.

7. An image data processing method comprising the steps of:

storing image data as contour data of a first resolution in a first storage means;

storing the image data as color data of a resolution lower than the first resolution in a second storage means, the color data corresponding to a plurality of the contour data;

reading a first number of data which are adjacent to each other of the contour data stored in said first storage means and a second number of data which are adjacent to each other of the color data including the color data corresponding to the plurality of the contour data stored in said second storage means; and

selecting one color data from among the read second number of the color data at the position of each of the read first number of the contour data,

wherein a value of an area surrounded by the contour data is generated by repeating said reading step and said selecting step.

8. An image data processing method according to claim 7, wherein the contour data comprises picture element data in which one picture element corresponds to one bit, and wherein the color data comprises picture element data in which one picture element corresponds to a plurality of bits.

9. An image data processing method according to claim 7, further comprising the step in which the image generated in said generation step is output to an output means.

10. An image data processing method according to claim 9, wherein the image output in said output step has the same resolution as the first resolution.