Method for focus control
First Claim
1. A method of focusing an optical system, comprising:
- (a) generating a plurality of digital images each obtained with a different focus setting of the optical system within a desired focusing range;
(b) analyzing the digital images to generate for each image a score by comparing first groups of pixels chosen from the image and having randomly chosen positional relationships with respect to one another with randomly positioned second groups chosen from the same image such that the pixels of each second group have the same respective positional relationships with respect to one another as the pixels of the first group with which it is compared have to one another, the score associated with each image being a function of the number of mismatches obtained with said comparisons; and
choosing that focus setting that corresponds to the image having a score indicative of the largest number of mismatches relative to the other images.
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Abstract
A camera or other optical system is focused by generating a plurality of digital images each obtained with a different focus setting of the optical system. These images are analysed to generate for each image a score (S) by comparing first groups of pixels chosen from the image with second groups chosen from the image such that the pixels of each second group have same respective positional relationships with respect to one another as the pixels of the first group with which it is compared have to one another, the score (S) being a function of the number of matches obtained with said comparisons. The focus setting that gives the score corresponding to the largest number of matches is chosen.
43 Citations
2 Claims
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1. A method of focusing an optical system, comprising:
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(a) generating a plurality of digital images each obtained with a different focus setting of the optical system within a desired focusing range; (b) analyzing the digital images to generate for each image a score by comparing first groups of pixels chosen from the image and having randomly chosen positional relationships with respect to one another with randomly positioned second groups chosen from the same image such that the pixels of each second group have the same respective positional relationships with respect to one another as the pixels of the first group with which it is compared have to one another, the score associated with each image being a function of the number of mismatches obtained with said comparisons; and choosing that focus setting that corresponds to the image having a score indicative of the largest number of mismatches relative to the other images. - View Dependent Claims (2)
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Specification