Method and apparatus for determining points of interest on an image of a camera calibration object
First Claim
1. A method comprising:
- receiving an array of pixels produced by a camera, the pixels corresponding to an image of a calibration object, the calibration object having a known reference pattern;
classifying each pixel of the image as light or dark;
extracting contours from the image by identifying lines between light and dark pixels;
comparing the extracted contours to the shapes of the known reference pattern; and
identifying the shapes of the known reference pattern in the image using the extracted contours.
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Accused Products
Abstract
The present invention allows for the locations of points of interest in a calibration object in a calibration image for a digital camera to be identified automatically. The image is an array of pixels corresponding to the calibration object, which has a known reference pattern. In a preferred embodiment, the invention includes receiving an array of pixels produced by a camera, classifying each pixel of the image as light or dark, extracting contours from the image by identifying lines between light and dark pixels, comparing the extracted contours to the shapes of the known reference pattern, and identifying the shapes of the known reference pattern in the image using the extracted contours. Preferably, the image is a color image, and the color information in the pixels of the image are converted into gray scale values to render the image as a gray scale image before the pixels are classified. Classifying each pixel includes applying a brightness threshold to each pixel of the image to classify those pixels having a brightness greater than the threshold as light and those below the threshold as dark.
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Citations
19 Claims
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1. A method comprising:
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receiving an array of pixels produced by a camera, the pixels corresponding to an image of a calibration object, the calibration object having a known reference pattern;
classifying each pixel of the image as light or dark;
extracting contours from the image by identifying lines between light and dark pixels;
comparing the extracted contours to the shapes of the known reference pattern; and
identifying the shapes of the known reference pattern in the image using the extracted contours. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A machine-readable medium having stored thereon data representing sequences of instructions which, when executed by a processor, cause the processor to perform operations comprising:
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receiving an array of pixels produced by a camera, the pixels corresponding to an image of a calibration object, the calibration object having a known reference pattern;
classifying each pixel of the image as light or dark;
extracting contours from the image by identifying lines between light and dark pixels;
comparing the extracted contours to the shapes of the known reference pattern; and
identifying the shapes of the known reference pattern in the image using the extracted contours. - View Dependent Claims (14, 15, 16)
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17. An apparatus for identifying a calibration object in an image comprising:
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means for receiving an array of pixels produced by a camera, the pixels corresponding to an image of a calibration object, the calibration object having a known reference pattern;
means for classifying each pixel of the image as light or dark;
means for extracting contours from the image by identifying lines between light and dark pixels;
means for comparing the extracted contours to the shapes of the known reference pattern; and
means for identifying the shapes of the known reference pattern in the image using the extracted contours. - View Dependent Claims (18, 19)
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Specification