1. A system for high dynamic range imaging, the system comprising: an image sensor comprising an array of light-sensing elements, wherein the image sensor detects an image of a scene and provides pixel values that represent light intensities impinging on respective ones of the light-sensing elements; a mask interposed between the scene and the array of light-sensing elements of the image sensor, wherein the mask has a plurality of light-transmitting cells that attenuate the intensity of light transmitted through the mask onto the light-sensing elements, the transparency of each of the cells of the mask being alterable by applying a respective exposure control signal to the mask; a mask controller coupled to the image sensor that receives the pixel values provided thereby and computes and applies exposure control signals to the mask so that the intensity of the light transmitted onto the light-sensing elements is attenuated by brightness level amounts that vary spatially across the array of light-sensing elements, wherein the scene is exposed to the light-sensing elements in a spatially varying manner, each of the light-sensing elements having a corresponding exposure value indicative of the transparency of the cells through which light impinging on the light-sensing element passes; an image processor coupled to the image sensor for receiving the pixel values provided thereby, wherein the image processor determines high dynamic range image data using at least the pixel values as function of the exposure values.