The relation between accuracy and size of structure element for vehicle detection with high resolution highway aerial images

It is a robust and efficient method that utilizes morphological operators, and Otsu threshold together with GIS road vector to detect vehicles from high resolution highway aerial images. Our previous experiments showed that the method resulted in a high correctness, completeness, and quality. However, we did not discuss the relation between the accuracy and the size of structure element for vehicle detection with high resolution highway aerial images. The space resolution of our aerial images is 0.15×0.15m, and most vehicles´ size is normally 5×2m, approaching 34×14 pixels. Thus, we selected a disc as structure element, but the disc´s radius should be less than 7 pixels. We compared the vehicle detection accuracy with 3 pixels, 4 pixels, 5 pixels, 6 pixels, and 7 pixels of disc with different size. Our result showed that the radius with 5 pixels or 6 pixels obtained the highest accuracy.