Color enhancement for images from digital camera using a transformation-free approach

Digital color images, in three color channels, are capable of presenting hue, saturation, and intensity perceptions to the human visual system. Improvement on color images quality should therefore be considered to simultaneously enhance all these attributes. An efficient approach was here developed aiming at mitigating the heavy computational burden, in conventional approaches, arising from the need to transform the source color space into an alternative working space. Color correction based on the white-point assumption is first carried out, and then enhancement is derived from an intensity-guided operation that simultaneously improves the contrast and saturation qualities. Experiments were conducted using a collection of real-world images captured under various environment conditions and enhancements were obtained both in subjective viewing and metrics in colorfulness, saturation and contrast.