The invention relates to a method, apparatus, imaging module and program for improving image quality in a digital image. The digital image according to the invention is captured with an imaging module including an imaging optics (101) and an image sensor (102), where the image is formed through the imaging optics (101) onto the light sensitive image sensor (102). According to embodiments of the present invention vignetting effect of the digital image captured with the imaging module (101, 102) is determined and compensated separately for at least two of the primary color components of the imaging module (101, 102).