Accurate positioning method for calibration point center coordinate

Abstract

The present invention relates to a precise positioning method for a calibration point center coordinate. The method comprises the steps of: drawing a calibration point and acquiring a grayscale imageof the calibration point; performing a thresholding operation and connected domain detection on the grayscale image to obtain a calibration point region; calculating to obtain the center coordinate ofthe connected domain of the calibration point and the circumscribed rectangle of the connected domain, and expanding the size of the circumscribed rectangle; according to the size of the circumscribed rectangle and the center coordinate, extracting the contour corresponding to the connected domain of the calibration point of the corresponding region in the grayscale image; carrying out circular fitting to obtain the initial center point of the contour; taking the center point as the center, emitting radiation to the surrounding area, and calculating the gradient amplitude; traversing all thestar rays to obtain the maximum point of the gradient value on each star ray, marking the maximum point as a key point, and completing the circular fitting through the key point to obtain a circle; and reviewing the obtained circle and verifying the positioning result. According to the method disclosed by the present invention, the problems of solving the center coordinate of the positioning areawith high precision and satisfying the positioning accuracy to a great degree are implemented.

Description

technical field [0001] The invention relates to the field of projection interaction technology, in particular to a method for precise positioning of center coordinates of a calibration point. Background technique [0002] Projection interactive system is a convenient way of human-computer interaction. Use the projection interaction system to realize multi-touch, and realize the touch interaction function under the large-scale projection screen, such as multi-person interactive games, multi-person interactive operations in children's teaching, etc. Calibrating the projection area and the display area and establishing a mapping relationship are crucial processes in the projection interaction system. The precise positioning of the calibration points directly affects the quality of the calibration. [0003] This patent proposes a method (star ray method), which can obtain the sub-pixel coordinates of the calibration points, thereby providing high-quality mapping point coordina...

AI Technical Summary

Problems solved by technology

[0004] For the current coordinate calibration, it is mainly by obtaining the positioning area, and then using the center of gravity of the positioning area as the center of the positioning area to achieve precise positioning, but for irregular areas, such as elliptical shapes or areas with jagged boundaries , if the center of gravity of the area is used as the center of the positioning area to achieve precise positioning, the accuracy often has certain deficiencies. For irregular areas, there will be a large error between the center of gravity and the center of precise positioning

Therefore, this method is not well suited for precise positioning in various regions

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