Dynamic computation of lens shading

Abstract

Embodiments of the present disclosure utilize captured image information to dynamically determine a lens shading surface being experienced by an imaging device or camera under current conditions. The lens shading surface is then used to apply a correction to the pixels of captured images to compensate for effects of lens shading.

1 . An image processing method, comprising:
 capturing a sequence of images via an image sensor, wherein the captured images have a global motion shift between them;   tracking a relative global motion displacement between the captured images;   calculating a ratio between an intensity level at a first image of the captured images and an intensity level of a same object point at a second image of the captured images; and   based on the ratios calculated, determining a lens shading surface profile.   
     
     
         2 . The method of  claim 1 , further comprising:
 determining a level of light source illuminating a scene recorded in the captured images and providing a measurement for white balance in the captured images.   
     
     
         3 . An image processing system, comprising:
 an image sensor to capture image data; and   at least one image processor that receives a plurality of captured image data and detects a global motion that is present during capturing of the captured image data, wherein the global motion is used to estimate effects of lens shading on the captured image data.   
     
     
         4 . The system of  claim 3 , wherein the captured image data is not characterized by a flat illumination field. 
     
     
         5 . The system of  claim 3 , wherein the at least one image processor dynamically corrects subsequently captured image data for the effects of lens shading. 
     
     
         6 . The system of  claim 5 , wherein the at least one image processor corrects newly captured image data for the effects of lens shading using prestored corrective factors that are not based on the captured image data when a condition in which the captured image data is captured is determined to not be conducive to using corrective factors based on the captured image data. 
     
     
         7 . The system of  claim 5 , wherein the at least one image processor corrects newly captured image data for the effects of lens shading using corrective factors that are based on the captured image data from a single image when a condition in which the captured image data is captured is determined to not be conducive to using corrective factors based on the captured image data from multiple images. 
     
     
         8 . The system of  claim 3 , wherein the at least one image processor determines a white balance level of the captured image data based on an estimation of the effects of lens shading. 
     
     
         9 . The system of  claim 3 , wherein the at least one image processor determines a motion estimation of the image sensor that captured the captured image data based on an estimation of the effects of lens shading. 
     
     
         10 . The system of  claim 3 , wherein the at least one image processor continually captures the captured image data as part of a preview mode and continually determines the effects of lens shading during the preview mode. 
     
     
         11 . An image processing method, comprising:
 receiving at least one captured image via an image sensor;   detecting a global motion that is present during capturing of the at least one captured image; and   computing an estimate of effects of lens shading on the at least one captured image from changes in intensity values of pixels in the at least one captured image during a global motion shift.   
     
     
         12 . The method of  claim 11 , wherein responsive to selecting to forgo computing the estimate of lens shading using inter image analysis of a plurality of captured image data, the estimate of the effects of lens shading is computed using intra image analysis of a single captured image, wherein the at least one captured image is the single captured image. 
     
     
         13 . The method of  claim 11 , wherein the estimate of the effects of lens shading is computed using at least inter image analysis of a sequence of captured image data, wherein the at least one captured image is the sequence of captured image data. 
     
     
         14 . The method of  claim 11 , further comprising:
 dynamically correcting subsequently captured image data for the effects of lens shading that has been previously computed for current lighting conditions.   
     
     
         15 . The method of  claim 14 , further comprising:
 correcting newly captured image data for the effects of lens shading using prestored corrective factors that are not based on the at least one captured image when a condition in which the at least one captured image is captured is determined to not be conducive to using corrective factors based on the at least one captured image.   
     
     
         16 . The method of  claim 15 , wherein the condition comprises a changing illumination level in the at least one captured image, wherein the at least one captured image comprises a plurality of captured images. 
     
     
         17 . The method of  claim 15 , wherein the condition comprises a local motion being detected in a scene that is a subject of the at least one captured image. 
     
     
         18 . The method of  claim 11 , further comprising:
 determining a white balance level of the at least one captured image based on an estimation of the effects of lens shading.   
     
     
         19 . The method of  claim 11 , further comprising:
 determining a motion estimation of the image sensor that captured the at least one captured image based on an estimation of the effects of lens shading.   
     
     
         20 . The method of  claim 11 , wherein the at least one captured image comprises a plurality of captured images that are continuously captured as part of a preview mode and the effects of lens shading are continuously determined during the preview mode.