A method and apparatus is provided for efficiently and automatically removing unwanted temporal lighting variations from image sequences. Specifically, temporal light variations from a sequence of images are removed by a process of selecting a reference image (R) and designating a portion of the reference image as a reference image region (M), designating a first portion of at least one base image (F) of the sequence of images as a first selected image region (M') and a second portion as a second selected image region (M"), generating a color mapping by comparing the selected image region of the base image (M') with the reference image region of the reference image frame (M), and applying the color mapping to the second selected image region (M") of the base image (F) to generated a corrected image (F'). Three separate methods of performing the color mapping are disclosed.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is related to co-pending and commonly assigned U.S. patent application Ser. No. 08/769,973 entitled "Method of Adjusting Image Pixel Values Within An Image Sequence by Interpolation of Target Cumulative Histograms for Images to be Adjusted", filed Dec. 19, 1996. Now U.S. Pat. No. 5,793,886, issued Aug. 11, 1998.
A method for compressing a sequence of digital images includes: comparing a reference image of the sequence of digital images to a subsequent image of the sequence of digital images. In response to the reference and subsequent images being the same within a predetermined threshold, 1) a count of a number of images discarded is incremented, 2) the subsequent image is discarded, and 3) the comparing step is repeated with a next subsequent image. In response to the reference and subsequent images not being within the predetermined threshold, 1) the count is initialized and 2) the comparing step is repeated using the subsequent image as the reference image. Rather than comparing whole images corresponding portions of the images can be compared and compressed independently.
A method for removing flicker in a sequence of images, wherein each image in the sequence of images includes a plurality of pixels. The method includes providing a sequence of images including a source image and a target image, defining a plurality of regions of interest in the source image and a plurality of spatially counterpart regions of interest in the target image, measuring an image quality for all of the pixels in each of the regions of interest in the source image, measuring an image quality for all of the pixels in each of the spatially counterpart regions of interest in the target image, and generating a corrected source image on a region of interest basis depending on the image quality for the pixels in each of the plurality of regions of interest in the source image and the spatially counterpart regions of interest in the target image.
If only a specific color and its nearby colors of image data are adjusted, density discontinuation occurs in the image as a whole. If masking is performed to avoid this problem, the adjustment range cannot be bounded, so the processing time increases. On an adjustment parameter designating unit, a user designates, as parameters, a reference color, the adjusted value of the reference color, and an adjustment region in a color space. A coordinate transformer transforms the coordinates of image data as an element of a color correction table, on the basis of a transformation matrix for transformation to an object color space. This transformation matrix is formed on the basis of the parameters by a transformation matrix calculator. If a region determinator determines that the image data is in the adjustment region, an adjusted value calculator calculates an adjusted value on the basis of the parameters.
