IMAGE PROCESSING DEVICE AND METHOD

• US 20100066848A1
• Filed: 12/22/2008
• Published: 03/18/2010
• Est. Priority Date: 09/17/2008
• Status: Active Grant

• Current Assignee: Silicon Motion Incorporated California (Silicon Motion)
• Original Assignee: Silicon Motion Incorporated California (Silicon Motion)
• Inventors: Wang, Yung-Te, Chen, Yung-Wei
• Granted Patent: US 8,203,618 B2
• Time in Patent Office: Days
• US Class Current: 348/222.100
• CPC Class Codes: H04N 19/124 Quantisation
• CPC Class Codes: H04N 19/152 by measuring the fullness of the transmission buffer
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/625 using discrete cosine transform [DCT]
• CPC Class Codes: H04N 19/91 Entropy coding, e.g. variable length coding [VLC] or arithmetic coding

Abstract

An image processing device including a camera, a discrete signal processor (DSP) and an output device is disclosed. The camera provides image data for the DSP to process. The DSP samples sub-image data to generate a first image processing signal, discrete cosine transforms the first image processing signal to generate a second image processing signal, uses a quantization table to quantize the second image processing signal to generate a third image processing signal, zig-zag scans the third image processing signal to generate a fourth image processing signal, and Huffman codes the fourth image processing signal to generate an output image signal. The DSP adjusts a cut point of a next fourth image processing signal according to the size of the fourth image processing signal so as to control the size of a next output image signal. The output device outputs the output image signal.

Claims

1. An image processing method for processing at least one image data, comprising:

sampling sub-image data to generate a first image processing signal;

discrete cosine transforming the first image processing signal to generate a second image processing signal;

quantizing the second image processing signal according to a quantization table so as to generate a third image processing signal;

zig-zag scanning the third image processing signal to generate a fourth image processing signal;

Huffman coding the fourth image processing signal to generate an output image signal; and

adjusting a cut point of a next fourth image processing signal according to the size of the fourth image processing signal so as to control the size of a next output image signal.

2. The image processing method as claimed in claim 1, wherein the fourth image processing signal following the cut point is zero-valued to control the size of the fourth image processing signal.

3. The image processing method as claimed in claim 1, wherein the image data comprises at least two sub-image data each having respective cut points.

4. The image processing method as claimed in claim 3, further comprising:

adjusting the quantization table of the next image data according to each cut point from the image data.

5. The image processing method as claimed in claim 4, wherein the quantization table comprises at least two values and a coefficient is provided for multiplying the quantization table to adjust the quantization table of the next image data.

6. The image processing method as claimed in claim 1, further comprising:

adjusting the quantization table and the cut point to control the size of the fourth image processing signal.

7. The image processing method as claimed in claim 6, wherein the sub-image data and the quantization table are of a respective N×

N data matrix.

8. An image processing device, comprising:

a camera for providing at least one image data;

a digital signal processor for processing the image data, wherein the digital signal processor samples sub-image data to generate a first image processing signal, discrete cosine transforms the first image processing signal to generate a second image processing signal, uses a quantization table to quantize the second image processing signal to generate a third image processing signal, Zig-Zag scans the third image processing signal to generate a fourth image processing signal, Huffman codes the fourth image processing signal to generate an output image signal, and adjusts a cut point of a next fourth image processing signal according to the size of the fourth image processing signal so as to control the size of a next output image signal; and

an output device for outputting the output image signal.

9. The image processing device as claimed in claim 8, wherein the fourth image processing signal following the cut point is zero-valued to control the size of the fourth image processing signal.

10. The image processing device as claimed in claim 8, wherein the image data comprises at least two sub-image data each having respective cut point.

11. The image processing device as claimed in claim 10, wherein the quantization table of the next image data is adjusted according to each cut point from the image data.

12. The image processing device as claimed in claim 11, wherein the quantization table comprises at least two values and a coefficient is provided for multiplying the quantization table to adjust the quantization table of the next image data.

13. The image processing device as claimed in claim 8, the quantization table and the cut point is adjusted to control the size of the fourth image processing signal.

14. The image processing device as claimed in claim 8, wherein the sub-image data and the quantization table are of a respective N×

N data matrix.

15. The image processing device as claimed in claim 8, wherein the output device is a universal serial bus (USB) device.

16. The image processing device as claimed in claim 8, wherein the image processing device comprises a web camera and a Joint Photographic Experts Group (JPEG) image processing device.

17. An image processing method for processing at least one image data, comprising:

quantizing a first image signal of the image data according to a quantization table so as to generate a second image signal;

zig-zag scanning the second image signal to generate a third image signal;

Huffman coding the third image signal to generate an output image signal;

adjusting a cut point of a next third image signal according to the size of the third image signal so as to control the size of a next output image signal; and

adjusting the quantization table of the next image data according to the cut point from the image data,

wherein a coefficient is provided for multiplying the quantization table to adjust the quantization table of the next image data.