Methods and systems for mitigating persistence in photodetectors
AssigneeBall Aerospace & Technologies Corp.
InventorAlex Harwit
Life of this patent
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Abstract
Image sensor systems and methods that mitigate the effects of electronic image sensor persistence are provided. The mitigation of persistence is achieved by flooding the pixels of the image sensor with light, saturating all of the pixels, prior to the collection of desired image data. Moreover, after saturating the pixels, but prior to collecting the desired image, the image sensor is reset and operated to take an image of a black scene. Due to persistence from the prior saturation step, the image of the black scene appears as a gray image. The image sensor is then optionally reset and is again saturated. After another reset operation, a desired image is obtained. The gray image is then subtracted from the desired image, to substantially correct for the effects of persistence in that image.
Claims23
A method, comprising:
- calibrating an image sensor, including:
- saturating the image sensor with input light;
- after saturating the image sensor with input light, resetting the image sensor;
- after resetting the image sensor, operating the image sensor to take a first image of a dark scene;
- and
- generating a reference image, wherein the reference image is at least in part based on the first image of the dark scene;
- and
- obtaining a first corrected image, including:
- saturating the image sensor with input light;
- after saturating the image sensor with input light, resetting the image sensor;
- after resetting the image sensor, operating the image sensor to obtain a first desired image;
- and
- subtracting the reference image from the first desired image to form the first corrected image.
A method, comprising:
- calibrating an image sensor, including:
- saturating the image sensor with input light;
- resetting the image sensor;
- operating the image sensor to take a first image of a dark scene;
- and
- generating a reference image, wherein the reference image is at least in part based on the first image of the dark scene;
- and
- obtaining a first corrected image, including:
- saturating the image sensor with input light;
- resetting the image sensor;
- operating the image sensor to obtain a first desired image;
- and
- subtracting the reference image from the first desired image to form the first corrected image;
- and
- the method further comprising:
- after operating the image sensor to take the first image of the dark scene, repeating the steps of saturating the image sensor with input light, resetting the image sensor, and operating the image sensor to take a second image of the dark scene, wherein the reference image is an average of the first and second images of the dark scene.
A method, comprising:
- first saturating a plurality of pixels of an image sensor with input light, wherein first saturating the plurality of pixels of the image sensor includes exposing all of the pixels in the plurality of pixels of the image sensor to an amount of illumination light above a maximum amount that can be measured by the pixels in the plurality of pixels of the image sensor;
- after first saturating the plurality of pixels of the image sensor, first resetting the plurality of pixels of the image sensor;
- and
- immediately after first resetting the plurality of pixels of the image sensor, using the plurality of pixels of the image sensor to collect a first image that includes light from a first scene.
An imaging system, comprising:
- an image sensor, wherein the image sensor includes a plurality of pixels;
- a lens assembly, wherein the lens assembly directs incident light to the image sensor;
- a light source, wherein the light source is operable to provide light to the image sensor;
- a memory;
- and
- a processor,
- wherein the processor controls the light source to provide light to the image sensor, wherein the light provided by the light source to the image sensor saturates the plurality of pixels of the image sensor, wherein saturating the plurality of pixels of the image sensor includes exposing all of the pixels in the plurality of pixels of the image sensor to an amount of illumination light above a maximum amount that can be measured by the pixels in the plurality of pixels of the image sensor, and wherein following saturating the plurality of pixels of the image sensor the processor operates the image sensor to take an image of a scene of interest.
Dependencies are inferred from the claim text.