Method for enlargement/reduction of image data in digital image processing system and circuit adopting the same

• US 5,901,274 A
• Filed: 12/05/1996
• Issued: 05/04/1999
• Est. Priority Date: 04/30/1994
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Oh, Hyang-su
• Primary Examiner(s): Coles, Edward L.
• Assistant Examiner(s): Pokrzywa, Joseph R.
• Application Number:
  US08/760,256
• Time in Patent Office: 880 Days
• Field of Search: 395/102, 358/451, 382/298, 382/299, 345/127, 345/128, 348/561, 348/581
• US Class Current: 358/1.2
• CPC Class Codes: G06T 3/40 Scaling of whole images or parts thereof, e.g. expanding or contracting
• CPC Class Codes: G06T 3/4007 based on interpolation, e.g. bilinear interpolation image demosaicing G06T3/4015; edge-driven or edge-based scaling G06T3/403
• CPC Class Codes: G06V 10/32 Normalisation of the pattern dimensions
• CPC Class Codes: H04N 1/393 Enlarging or reducing
• CPC Class Codes: H04N 1/3935 with modification of image resolution, i.e. determining the values of picture elements at new relative positions

Abstract

An image data enlargement/reduction method for use in a digital image processing system, performs enlargement and reduction of image data by employing a small quantity of data from a look-up table while satisfying a large range of enlargement and reduction operations as requested by a user, with a simplified circuit structure. Enlargement/reduction data is calculated by a microprocessor so that the zooming ratio can be easily modified by a software change.

Claims

1. An image data enlargement/reduction method in a digital image processing system which comprises a look-up table (LUT) where enlargement/reduction data are stored and a memory for storing processed enlargement/reduction data, and which enlarges/reduces input image data in accordance with a user-designated zooming ratio, the method comprising:

(a) dividing the user-designated zooming ratio by 100 and calculating a quotient and a remainder;

(b) performing a first reduction process reducing image data with reference to the data stored in the LUT if the quotient is less than one;

(c) performing a first enlargement process enlarging image data with reference to the data stored in the LUT if the quotient is greater than one and the remainder is not zero;

(d) performing a second enlargement process, if the quotient is at least one and the remainder is zero; and

(e) writing enlargement/reduction data calculated via said steps in (a) to (d) into the memory.

2. The image data enlargement/reduction method according to claim 1, wherein the LUT table stores data for enlargement and reduction operations corresponding to 1% through 99% ratios in steps of 1%.

3. The image data enlargement/reduction method according to claim 1, comprising reading the written enlargement/reduction data and verifying whether the read data is the same as original data.

4. The image data enlargement/reduction method according to claim 1, wherein the first enlargement and reduction process reads the data corresponding to the user-designated zooming ratio from the enlargement/reduction data stored in the LUT, extends the read data into one scanning line of data corresponding to the user-designated zooming ratio, and calculates enlargement/reduction data for the first enlargement/reduction process.

5. An image data enlargement/reduction device for enlarging and reducing image data input to a digital image processing system and for outputting an image corresponding to a user-designated zooming ratio, the device comprising:

a first memory for storing a look-up table (LUT) for use in enlargement/reduction the LUT storing data for enlargement and reduction operations corresponding to 1% through 99% ratios in steps of 1%;

a microprocessor for calculating enlargement/reduction data according to the zooming ratio, using the LUT stored in said first memory;

a second memory for storing the enlargement/reduction data output by said microprocessor; and

a third memory for storing enlargement/reduction data extended into one scanning line by said microprocessor, employing the enlargement/reduction data stored in said second memory.

6. The image data enlargement/reduction device according to claim 5, comprising:

first and second line memories for storing the input image data to be enlarged/reduced, in units of one scanned line, respectively, wherein the data in the LUT indicate the addresses of said first and second line memories to be read out.

7. The image data enlargement/reduction device according to claim 6, comprising:

a first counter for counting a sync signal of the image data in order to write the one scanned line units of the image data, into addresses of said first and second line memories.

8. The image data enlargement/reduction device according to claim 7, comprising a second counter for counting a sync signal of the image data in order to output the data stored in said third memory as addresses of said first and second line memories, so that data can be written in said third memory by said microprocessor and so that enlargement/reduction can be performed with respect to the user-designated zooming ratio during a scanning operation.

9. The image data enlargement/reduction device according to claim 6, comprising:

a frequency divider for frequency-dividing a line sync signal such that read and write operations of said first and second line memories are performed alternately.

10. The image data enlargement/reduction device according to claim 6, comprising:

a first buffer for designating a write and read-out address to said first and second line memories;

a second buffer for writing image data to be enlarged/reduced into said first and second line memories;

a third buffer for outputting the enlarged/reduced image data read out from said first and second line memories; and

a fourth buffer for said microprocessor to read/write the data of said third memory.

11. The image data enlargement/reduction device according to claim 5 which reads out the data corresponding to the user-designated zooming ratio from the enlargement/reduction data stored in the LUT, extends the read-out data into one scanning line of data according to the enlargement/reduction rate, and calculates enlargement/reduction data for an enlargement/reduction process.

12. The image data enlargement/reduction device according to claim 11, wherein the enlargement/reduction data for the enlargement process is calculated by a second enlargement process with reference to the LUT.