US 7,626,632 B2 · Method and apparatus for correcting digital images

Abstract

The present invention provides methods, systems, and computer-program products for correcting image streaking, light scattering, and other effects in digital images generated by multispectral sensors. An image frame, a plurality of image frames from the digital sensor when exposed to dark, and a plurality of image frames from the digital sensor when exposed to light are received. The received image frame is corrected based on the received plurality of image frames exposed to dark and the plurality of image frames exposed to light. The received image frames are enhanced based on characteristics of the digital sensor. Light scattering effects are removed from the corrected image frame based upon characteristics of the digital sensor.

Claims38

Dependent claims

A method for correcting an image frame, the method comprising:

receiving a first image frame of a scene from a digital sensor;
receiving a first plurality of image frames from the digital sensor exposed to a dark current level;
receiving a second plurality of image frames from the digital sensor exposed to a reference intensity level;
computing a difference between the first plurality of images and the second plurality of images over a stable region of interest;
and
using the difference to correct the first image frame for light scattering.

3 more elements

A method for correcting an image frame, the method comprising:

receiving a first image frame from a digital sensor;
receiving a plurality of image frames from the digital sensor exposed to light below a first predefined luminance level;
receiving a plurality of image frames from the digital sensor exposed to light above a second predefined luminance level;
and
correcting the first received image frame based on the received plurality of image frames exposed to light below the first predefined luminance level and the plurality of image frames exposed to light above the second predefined luminance level;
wherein each image frame includes a plurality of frame units and correcting includes calculating a mean value for each frame unit of the plurality of image frames exposed to light below the first predefined luminance level;
calculating a mean value for each frame unit of the plurality of image frames exposed to light above the second predefined luminance level;
generating a second image frame by subtracting the calculated mean value for each frame unit of the plurality of image frames exposed to light below the first-predefined luminance level from the corresponding frame unit in the first image frame;
generating a third image frame by subtracting the calculated mean value for each frame unit of the plurality of image frames exposed to light below the first predefined luminance level from the calculated mean value for each corresponding frame unit of the plurality of image frames exposed to light above the second predefined luminance level;
generating a fourth image frame by dividing each frame unit in the second image frame from the corresponding frame unit in the third image frame;
calculating an average of frame units within a predefined center section of the third image frame;
and generating a fifth image frame by multiplying each frame unit in the fourth image frame by the calculated average of the center section frame units, thereby producing a corrected image frame of the received image frame.

9 more elements

A system for correcting an image frame produced by a digital sensor, the system comprising a processor programmed to receive a first image frame from the digital sensor, a plurality of image frames exposed to light below a first predefined luminance level, and a plurality of image frames exposed to light above a second predefined luminance level;

and to correct the first image frame for light scattering based on a difference between the received plurality of image frames exposed to light below the first predefined luminance level and the plurality of image frames exposed to light above the second predefined luminance level.

An article comprising a computer readable medium and a computer-program product residing on the computer readable medium for correcting an image frame produced by a digital sensor, including:

receiving a first image frame, a plurality of image frames exposed to light below a first predefined luminance level, and a plurality of image frames exposed to light above a second predefined luminance level;
and
correcting the first image frame for light scattering based on a difference between the received plurality of image frames exposed to light below the first predefined luminance level and the plurality of image frames exposed to light above the second predefined luminance level.

An article comprising a computer readable medium and a computer-program product residing on the computer readable medium for removing light scattering effects from an image frame generated by a digital sensor, the computer-program product including:

a first component configured to receive a first image frame from the digital sensor;
a plurality of image frames exposed to light below a first predefined luminance level, and a plurality of image frames exposed to light above a second predefined luminance level;
a second component configured to calculate an average value of frame units within a predetermined region of interest of the first image frame;
a third component configured to generate a second image frame by removing the calculated average value from each of the frame units of the first image frame;
a fourth component configured to separate the second image frame into a plurality of subarrays;
a fifth component configured to generate a total for each subarray by adding frame units of the respective subarray;
a sixth component configured to determine a distance of a frame unit of the second image frame from one of the subarrays;
a seventh component configured to determine the light scattering effect of the subarray upon the frame unit based upon the determined distance of the frame unit from the subarray and the light scattering effects;
an eighth component configured to generate a subarray light scattering effect by multiplying the determined light scattering effect by the generated total of the associated subarray;
a ninth component configured to return to the sixth component for all the subarrays;
a tenth component configured to generate a subarray effects total by adding all the generated subarray light scattering effects;
an eleventh component configured to generate a final frame unit by subtracting the generated subarray effects total from the respective frame unit;
and
a twelfth component configured to return to the sixth component for processing all the frame units of the second image frame.

11 more elements

Dependencies are inferred from the claim text.

Method and apparatus for correcting digital images

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Method and apparatus for correcting digital images

Life of this patent

Abstract

Claims38