Figure 4

Finding contours of objects. This plot shows the contour of a neural structure obtained from successive slices. The contour in the first slice was initialized by manually drawing a circle around the neural structure, and then refined with the snake algorithm. The subsequent contours are initialized with the final contour of the previous slice, and then deformed to conform to the image data. The X and Y axis units are in pixels, and the Z axis represents the index number of each slice.