Veiling Glare in High Dynamic Range Imaging
Presented at SIGGRAPH 2007
The ability of a camera to record a high dynamic range image, whether by taking one snapshot or a sequence, is limited by the presence of veiling glare - the tendency of bright objects in the scene to reduce the contrast everywhere within the field of view. Veiling glare is a global illumination effect that arises from multiple scattering of light inside the camera's optics, body, and sensor. By measuring separately the direct and indirect components of the intra-camera light transport, one can increase the maximum dynamic range a particular camera is capable of recording. In this paper, we quantify the presence of veiling glare and related optical artifacts for several types of digital cameras, and we describe two methods for removing them: deconvolution by a measured glare spread function, and a novel direct-indirect separation of the lens transport using a structured occlusion mask. By physically blocking the light that contributes to veiling glare, we attain significantly higher signal to noise ratios than with deconvolution. Finally, we demonstrate our separation method for several combinations of cameras and realistic scenes.
|Figure 1: A strongly backlit still life
|Figure 2: Still life with glare removed
|Figure 2. A mock image of a snowboarder silhouetted by a full moon
|Figure 3. The snowboarder with the glare removed