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

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.