Intrinsic Images by Entropy Minimization

A method was recently devised for the recovery of an invariant image from a 3-band colour image. The invariant image, originally 1D greyscale but here derived as a 2D chromaticity, is independent of lighting, and also has shading removed: it forms an intrinsic image that may be used as a guide in recovering colour images that are independent of illumination conditions. Invariance to illuminant colour and intensity means that such images are free of shadows, as well, to a good degree. The method devised finds an intrinsic reflectivity image based on assumptions of Lambertian reflectance, approximately Planckian lighting, and fairly narrowband camera sensors. Nevertheless, the method works well when these assumptions do not hold. A crucial piece of information is the angle for an "invariant direction" in a log-chromaticity space. To date, we have gleaned this information via a preliminary calibration routine, using the camera involved to capture images of a colour target under ...

• Type: Conference
• Year: 2004
• Where: ECCV
• Authors: Graham D. Finlayson, Mark S. Drew, Cheng Lu
• Keywords: 3-band Colour Image, Colour Images, Computer Vision, Correct Shadow-free Image, ECCV 2004, Intrinsic Reflectivity Image, Invariant Image