An auto exposure method for a spatially-multiplexed-exposure (SME) high-dynamic-range (HDR) image sensor , comprising: retrieving raw image data from an exposure of the spatially-multiplexed-exposure high-dynamic-range image sensor, the raw image data including long-exposure pixel values from pixels of the spatially-multiplexed-exposure high-dynamic-range image sensor characterized by a long exposure time and short-exposure pixel values from pixels of the spatially-multiplexed-exposure high-dynamic-range image sensor characterized by a short exposure time; preprocessing the long-exposure pixel values and the short-exposure pixel values to remove therefrom long-exposure pixel values and short-exposure pixel values failing to meet one or more image quality requirements, wherein the step of preprocessing comprises scaling the long-exposure pixel values and the short-exposure pixel values to compensate for presence of an optical gradient filter between the spatially-multiplexed-exposure (SME) high-dynamic-range (HDR) image sensor and a scene represented by the raw image data; synthesizing , into an high-dynamic-range histogram, the long-exposure pixel values remaining after the step of preprocessing and the short-exposure pixel values remaining after the step of preprocessing; deriving a goodness metric from the high-dynamic-range histogram; adjusting at least one of the long exposure time and the short exposure time, based at least in part upon the goodness metric; and outputting the at least one of the long exposure time and the short exposure time, as adjusted, to the spatially-multiplexed-exposure high-dynamic-range image sensor. retrieving raw image data from an exposure of the spatially-multiplexed-exposure high-dynamic-range image sensor, the raw image data including long-exposure pixel values from pixels of the spatially-multiplexed-exposure high-dynamic-range image sensor characterized by a long exposure time and short-exposure pixel values from pixels of the spatially-multiplexed-exposure high-dynamic-range image sensor characterized by a short exposure time; preprocessing the long-exposure pixel values and the short-exposure pixel values to remove therefrom long-exposure pixel values and short-exposure pixel values failing to meet one or more image quality requirements, wherein the step of preprocessing comprises scaling the long-exposure pixel values and the short-exposure pixel values to compensate for presence of an optical gradient filter between the spatially-multiplexed-exposure (SME) high-dynamic-range (HDR) image sensor and a scene represented by the raw image data; synthesizing , into an high-dynamic-range histogram, the long-exposure pixel values remaining after the step of preprocessing and the short-exposure pixel values remaining after the step of preprocessing; deriving a goodness metric from the high-dynamic-range histogram; adjusting at least one of the long exposure time and the short exposure time, based at least in part upon the goodness metric; and outputting the at least one of the long exposure time and the short exposure time, as adjusted, to the spatially-multiplexed-exposure high-dynamic-range image sensor. <EOS>