Grayscale-weighted centroiding weights the pixel intensity to estimate the center of a circular image region such as a\r\nphotogrammetric target or a star image. This is easy to realize with good robustness; however, locating accuracy varies with weight.\r\nThere is no conclusion as to the relationship between weight and centroiding accuracy. To find this relationship and thus acquire\r\nthe highest achievable accuracy of centroiding, one must first derive the general model of centroiding as follows. (1) Set weighting\r\nas a function that includes the grayscale intensity of each pixel and two undetermined parameters ?? and ??. The centers were\r\ncalculated from the new weights. (2) Design an accuracy evaluation method for centroiding based on a virtual straight-line target\r\nto obtain the accuracy of centroiding with various parameters. With these parameter values and accuracy records, the accuracyparameter\r\ncurve can be fitted. In the end, simulations and experiments are conducted to prove the accuracy improvement of this\r\nvariable-weighted grayscale centroiding compared with traditional centroiding. The experimental result shows that the parameter\r\n?? contributes significantly to accuracy improvement.When ?? = 1.5, locating accuracy is 1/170 pixels. Compared to centroiding and\r\nsquared centroiding, the new locating method has a 14.3% and 10.6% accuracy improvement indicating that it improves locating\r\naccuracy effectively.
Loading....