Image signal processor supporting compensation operation for saturated pixel and method of operating the same

A method of operating an image signal processor, the method comprising:

• comparing an image data value for each of a plurality of unit pixels with a saturation threshold value to detect saturated pixels among the plurality of unit pixels;
• estimating channels for each of the plurality of unit pixels;
• performing a correlation calculation on some channels selected from among channels for each of the plurality of unit pixels;
• and
• selecting at least one color-transfer pixel from among non-saturated pixels of the plurality of unit pixels based on a result value of the correlation calculation, and performing a compensation operation on a target pixel of the plurality of unit pixels using the at least one color-transfer pixel, wherein performing the compensation operation on the target pixel comprises performing the compensation operation on a first pixel, selected from among the saturated pixels in a previous frame, and performing a compensation operation on a second pixel selected from among the saturation pixels, in a current frame,
• wherein a color correlation map, used in the compensation operation on the first pixel, and a color correlation map, used in the compensation operation on the second pixel, are the same.

An electronic device including an image sensor, the electronic device comprising:

• a saturation detecting unit configured to classify each of a plurality of pixels, corresponding to a digital signal output from the image sensor, as either a saturated pixel or a non-saturated pixel and to select a compensable pixel from among the saturated pixels;
• a color processing unit configured to estimate channel values for each color for each of a plurality of pixels and to perform a correlation calculation between the channel values for each color;
• and
• a saturation compensation unit configured to select at least one color-transfer pixel from among the non-saturated pixels based on the correlation calculation value between the channel values for each color and to perform a compensation operation on the compensable pixel based on the at least one color-transfer pixel,
• wherein:
• the saturation compensation unit is configured to select the at least one color-transfer pixel from among the non-saturated pixels in a low conversion gain (LCG) mode and is configured to select the compensable pixel from among the saturated pixels in a high conversion gain (HCG) mode, and
• correlation calculation values between the channel values for each color used in the LCG mode are the same as correlation calculation values between the channel values for each color used in the HCG mode.