Image compression method using saturated pixel, encoder, and electronic device

1. An image compression method for compressing image data generated by an image sensor, the image compression method comprising:

detecting a saturated pixel among a plurality of pixels included in a pixel group included in the image data, the saturated pixel having a pixel value exceeding a threshold value, and the plurality of pixels being adjacent to each other and having same color information;

generating a saturation flag indicating a position of the saturated pixel;

compressing the image data by comparing a reference pixel with at least one non-saturated pixel among the plurality of pixels included in the pixel group, the reference pixel being a non-saturated pixel among the plurality of pixels; and

outputting a bitstream including the saturation flag, a compression result, and a compression method.

2. The image compression method of claim 1 , wherein the generating of the saturation flag includes:

setting the position of the saturated pixel to a bit 1's; and

setting a position of the at least one non-saturated pixel to a bit 0's.

3. The image compression method of claim 1 , wherein a position of the reference pixel is predetermined.

4. The image compression method of claim 3 , wherein the reference pixel is compressed prior to the at least one non-saturated pixel.

5. The image compression method of claim 1 , wherein the compressing of the image data includes obtaining a difference value between a non-saturated pixel value of the at least one non-saturated pixel and a reference pixel value of the reference pixel.

6. The image compression method of claim 5 , wherein the reference pixel value corresponds to an average pixel value of pixels adjacent to each other and having same color information.

7. The image compression method of claim 5 , wherein the reference pixel value of the reference pixel corresponds to a median pixel value of pixels adjacent to each other and having same color information.

8. The image compression method of claim 1 , wherein

the bitstream includes a header field, and

the header field includes the compression method.

9. The image compression method of claim 1 , wherein the threshold value is at least 95% of an amount of information represented by the plurality of pixels.

10. The image compression method of claim 1 , wherein the outputting of the bitstream includes determining whether to output the saturation flag and the compression result based on a mode signal instructing to compress the plurality of pixels included in the image data except for the saturated pixel.

11. The image compression method of claim 10 , wherein the outputting of the bitstream further includes outputting the bitstream regardless of the mode signal based on at least two saturated pixels being detected.

12. A processor comprising an encoder for processing image data generated by an image sensor, the encoder configured to:

detect a saturated pixel among a plurality of pixels included in a pixel group, the saturated pixel having a pixel value exceeding a threshold value, and the plurality of pixels being adjacent to each other and having same color information;

generate a saturation flag indicating a position of the saturated pixel; and

compress the image data by comparing a reference pixel with at least one non-saturated pixel among the plurality of pixels included in the pixel group, the reference pixel being a non-saturated pixel among the plurality of pixels.

13. The processor comprising the encoder of claim 12 , wherein a position of the reference pixel is predetermined.

14. The processor comprising the encoder of claim 12 , wherein the pixel group includes four pixels.

15. The processor comprising the encoder of claim 12 , wherein the pixel group includes nine pixels.

16. The processor comprising the encoder of claim 12 , wherein the encoder is further configured to determine whether to compress the image data based on a mode signal instructing to compress the plurality of pixels included in the image data except for the saturated pixel.

17. The processor comprising the encoder of claim 12 , wherein the threshold value is at least 95% of an amount of information represented by the plurality of pixels.

18. An electronic device capturing an image, the electronic device comprising:

an image sensor including a pixel array and configured to output image data;

an image signal processor including an encoder, the encoder being configured to:

detect a saturated pixel among a plurality of pixels included in a pixel group, the saturated pixel having a pixel value exceeding a threshold value, and the plurality of pixels being adjacent to each other and having same color information;

generate a saturation flag indicating a position of the saturated pixel;

compress the image data by comparing a reference pixel with at least one non-saturated pixel among the plurality of pixels included in the pixel group, the reference pixel being a non-saturated pixel among the plurality of pixels; and

output a bitstream including a compression result, the saturation flag, and a compression method; and

an application processor including a decoder, the decoder being configured to reconstruct the image data by decoding the bitstream.

19. The electronic device of claim 18 , wherein the decoder is further configured to decode the at least one non-saturated pixel based on data reconstructed at a predetermined position of the reference pixel.

20. The electronic device of claim 18 , wherein the decoder is further configured to reconstruct the saturated pixel to a predetermined saturation value.