Adaptive dynamic range imaging: Optical control of pixel exposures over space and time

This paper presents a new approach to imaging that significantly enhances the dynamic range of a camera. The key idea is to adapt the exposure of each pixel on the image detector, based on the radiance value of the corresponding scene point. This adaptation is done in the optical domain, that is, during image formation. In practice, this is achieved using a spatial light modulator whose transmittance can be varied with high resolution over space and time. A real-time control algorithm is developed that uses acquired images to automatically adjust the transmittance function of the spatial modu-lator. Each captured image and its corresponding trans-mittance function are used to compute a very high dy-namic range image that is linear in scene radiance