I have a grayscale aerial photo, how do I segment the image and vectorize the boundaries of objects such as roof tops, parking lots and other homogenous areas?
R2V has a grayscale image segmentation function designed for this purpose. If the image is in relatively good quality, use the Image/Segmentation function directly. After the image is segmented, you’ll be prompted to select the grayscale threshold. Adjust the threshold so the regions you want to vectorize are in red color. Make sure the regions are separated from others when adjusting the threshold. Click on the “OK” button to continue the process. The boundaries are then vectorized automatically and the vector lines are displayed on top of the segmented image. Edit the lines to fill in gaps and remove redundant lines. You can use all the options under the Edit/Line Editor menu. When lines are completely edited and cleaned up, use the Vector/Create Polygon Layer function if you plan to create closed polygons.
