US 2021/0243352 A1 · AUTO EXPOSURE OF SPATIALLY-MULTIPLEXED-EXPOSURE HIGH-DYNAMIC-RANGE IMAGE SENSORS

Abstract

An auto exposure method for a spatially-multiplexed-exposure (SME) high-dynamic-range (HDR) image sensor includes (a) retrieving raw image data from an exposure of the spatially-multiplexed-exposure high-dynamic-range image sensor, (b) preprocessing long-exposure pixel values and short-exposure pixel values of the raw image data to remove therefrom long-exposure pixel values and short-exposure pixel values failing to meet one or more quality requirements, (c) 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, (d) deriving a goodness metric from the high-dynamic-range histogram, (e) adjusting at least one of the long exposure time and the short exposure time, based at least in part upon the goodness metric, and (f) 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.

Claims33

Dependent claims

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;
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.

4 more elements

The auto exposure method of claim, further comprising performing a plurality of iterations of the steps of retrieving, preprocessing, synthesizing, deriving, adjusting, and outputting, to determine an optimal set of the long exposure time and the short exposure time that minimizes the variance.

An auto exposure method for a spatially-multiplexed-exposure high-dynamic-range image sensor comprising:

(I) retrieving raw image data from an exposure of the spatially-multiplexed-exposure high-dynamic-range image sensor, wherein the raw image data includes long-exposure pixel values from long-exposure pixels of the spatially-multiplexed-exposure high-dynamic-range image sensor characterized by a long exposure time and short-exposure pixel values from short-exposure pixels of the spatially-multiplexed-exposure high-dynamic-range image sensor characterized by a short exposure time, (II) for each of a plurality of spatial regions of the spatially-multiplexed-exposure high-dynamic-range image sensor, evaluating saturation level of a selected long-exposure pixel in the spatial region, (III) for each of the spatial regions characterized by the long-exposure pixel value of the selected long-exposure pixel exceeding a saturation threshold, determining (i) a reduced short exposure time for the short-exposure pixels in the spatial region and (ii) an increased digital gain value that compensates for the reduced short exposure time, and (IV) for each of the spatial regions characterized by the long-exposure pixel value of the selected long-exposure pixel exceeding the saturation threshold, outputting the reduced short exposure time and the increased digital gain value to each short-exposure pixel in the spatial region.

Dependencies are inferred from the claim text.

Auto exposure of spatially-multiplexed-exposure high-dynamic-range image sensors

Life of this patent

Auto exposure of spatially-multiplexed-exposure high-dynamic-range image sensors

Life of this patent

Abstract

Claims33