2 skills found
maxkonovalov / MKGradientView🌈 Highly customizable Core Graphics based gradient view for iOS
Tajamul21 / Counter Top Corner DetectionThe robot needed to find the extreme edges of the counter-top and the sink. To detect the corners, we used three methods to obtain the coordinates of 8 corners (4-counter top and 4-sink) as shown in figure. The three methods were: 1. Finding corner points using P4P(4 point algorithm) 2. Finding corner points using RANSAC. 3. Finding corner points using colour segmentation. They are explained below. 4.1 Method 1: Finding corner points using P4P The counter top had round colour lables stuck on them in the four outer and inner corners. (See Figure 13 for an example.) The outer points A, B, C , D in figure 13 were segmented based on color and the coordinates were saved. Using 4 Point algorithm, we were able to re project the outer and inner corners of the counter-top with an average re-projection error of 0.489. We can also compute the 3D locations of these points with respect to the camera coordinate frame. 4.2 Method 2: Finding corner points using RANSAC RANSAC divides data into inliers and outliers and yields an estimate of the counter top plane, computed from a minimal set of inliers with greatest support. We Improved this initial estimate with a Least Squares (S) estimation over all inliers (i.e., standard minimization), and then we found the inliers w.r.t the L.S. fit, and re-estimated the plane using L.S. one more time. We used the 3D points (given by the camera) to find the counter plane using this method. We then identified the pixels corresponding to the plane in the corresponding colour image. To find the corners, we used Harris corner detector. Harris’ corner detector takes the differential of the corner score into account with reference to direction directly, instead of using shifting patches for every 45◦ angles, and has been proved to be more accurate in distinguishing between edges and corners. The implementation was done as follows: 1. Compute image intensity gradients in x- and y-directions.
