Image compression method, encoder, and camera module including the encoder

Patent metadata

Field	Value
Publication number	US-11627250-B2
Application number	US-202117183547-A
Country	US
Kind code	B2
Filing date	Feb 24, 2021
Priority date	Apr 29, 2020
Publication date	Apr 11, 2023
Grant date	Apr 11, 2023

Abstract

An image compression method to compress image data generated through a pixel array includes categorizing image data corresponding to a plurality of sub-pixels arranged adjacent to each other and generating first color information for a first color pixel; determining a reference value as a criterion for compressing the image data based on pixel values of the sub-pixels; comparing the pixel values of the sub-pixels with the reference value; and outputting results of the comparisons and the reference value.

First claim

What is claimed is:

1. An image compression method to compress image data generated through a pixel array, the method comprising:
categorizing image data corresponding to a first color pixel having a plurality of sub-pixels arranged adjacent to each other, and generating first color information for the first color pixel;
determining a reference value as a criterion for compressing the image data based on a pixel value of at least one of the plurality of sub-pixels; and
comparing pixel values of each of the plurality of sub-pixels with the reference value, and outputting comparison results.

2. The method of claim 1 , wherein the determining of the reference value comprises:
calculating an average pixel value of pixel values of the plurality of sub-pixels; and determining the average pixel value as the reference value.

3. The method of claim 1 , wherein the determining of the reference value comprises determining a pixel value of a first sub-pixel from among the plurality of sub-pixels as the reference value.

4. The method of claim 3 , wherein the determining of the pixel value of the first sub-pixel as the reference value comprises:
sorting the pixel values of the plurality of sub-pixels according to values thereof; and
determining the pixel value of the first sub-pixel having a median of the pixel values of the plurality of sub-pixels as the reference value.

5. The method of claim 4 , wherein the first sub-pixel is a sub-pixel having a smaller pixel value of two medians of sorted pixel values in response to a number of the plurality of sub-pixels being an even number.

6. The method of claim 3 , wherein the first sub-pixel is a sub-pixel arranged at a pre-determined position within a pixel cell from among the plurality of sub-pixels.

7. The method of claim 1 , wherein the categorizing of the image data into the first color pixel comprises:
buffering a pixel value of each of sub-pixels located in a first row from among the plurality of sub-pixels; and
receiving image data corresponding to sub-pixels located in a second row from among the plurality of sub-pixels.

8. The method of claim 1 , wherein:
the plurality of sub-pixels is four in number, and
the plurality of sub-pixels are arranged in a matrix form in the first color pixel.

9. The method of claim 1 , wherein:
the plurality of sub-pixels is nine in number, and
the plurality of sub-pixels are arranged in a matrix form in the first color pixel.

10. The method of claim 1 , wherein the first color information indicates any one of red, green, or blue.

11. The method of claim 1 , wherein the comparing of the pixel value of each of the plurality of sub-pixels comprises:
calculating a difference between the reference value and a pixel value of each of the plurality of sub-pixels,
outputting each difference as a comparison result, and
outputting the reference value.

12. An encoder for compressing image data generated through a pixel array, wherein the encoder is configured to categorize image data corresponding to a plurality of sub-pixels arranged adjacent to each other and generating first color information into a first color pixel; determine a reference value being a criterion for compressing the image data based on a pixel value of each of the plurality of sub-pixels; compare the pixel value of each of the plurality of sub-pixels with the reference value, and output comparison results and the reference value.

13. The encoder of claim 12 , wherein the reference value is an average value of pixel values of the plurality of sub-pixels.

14. The encoder of claim 12 , wherein:
the first color pixel is arranged in a 2×2 matrix form, and
the reference value is the second smallest pixel value from among pixel values of the plurality of sub-pixels.

15. The encoder of claim 12 , wherein:
the first color pixel is arranged in a 3×3 matrix form, and
the reference value is a median from among pixel values of the plurality of sub-pixels.

16. The encoder of claim 12 , wherein the reference value is a pixel value of a sub-pixel arranged at a pre-determined position from among the plurality of sub-pixels.

17. A camera module comprising:
an image sensor including a pixel array having a plurality of pixels that are arranged in a matrix form and respectively generate a pixel signal, the image sensor configured to convert light into an electrical signal by using photoelectric conversion elements and output image data; and
an encoder configured to output a bit stream generated by compressing the image data,
wherein the encoder categorizes a plurality of sub-pixels arranged adjacent to each other and generating first color information into a first color pixel, determines a reference value as a criterion for compressing the image data based on a pixel value of each of the plurality of sub-pixels, compares the pixel value of each of the plurality of sub-pixels with the reference value, and outputs comparison results and the reference value.

18. The camera module of claim 17 , wherein the reference value is any one of an average value or a median of pixel values of the plurality of sub-pixels.

19. The camera module of claim 17 , wherein the reference value is a pixel value of a sub-pixel arranged at a pre-determined position from among the plurality of sub-pixels.

20. The camera module of claim 17 , further comprising a memory,
wherein the memory buffers image data corresponding to sub-pixels located in a first row from among the plurality of sub-pixels, and
wherein the encoder receives image data corresponding to sub-pixels located in a second row from among the plurality of sub-pixels and compresses the image data based on a reception result and a buffering result.

Assignees

• Samsung Electronics Co Ltd

Inventors

• Lee Wonseok
• Song Seongwook
• Jang Hyukjae
• Jun Sungho
• Choi Yunseok

Classifications

• H04N23/80

  Camera processing pipelines; Components thereof · CPC title

• H04N19/186

  the unit being a colour or a chrominance component · CPC title

• H04N19/105

  Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction · CPC title

• H04N19/182 Primary

  the unit being a pixel · CPC title

• G06V10/56

  relating to colour · CPC title