An image signal processing method and system, which can greatly reduce the data
size upon transmitting an image signal or storing the signal in a storage medium,
and can obtain a high-quality image by preventing image quality after color processing
from deteriorating. According to the method for processing an image signal output
from an image sensing element, a compression step of compressing the image signal
and an expansion step of expanding the compressed image signal are executed without
executing color processing for executing at least white balance correction or correction,
and the color processing is executed after completion of the compression and expansion
steps, thereby preventing occurrence of block noise and high-frequency noise associated
with compressing/expanding image data after the color processing of the image signal.
