# Matlab binary image edge

Classical methods use the image gradient or approximations of the image gradient to detect edge location. If you have a noisy image it is a good practice to reduce the noise before detecting the edges. This is because noise might lead to false steps during edge detection, specially when gradient based methods are employed. Noise may produce unreliable oscillating derivative values across short distances. Let's investigate the profile of rows of our HELA image its red channel: Experiment the edge detection methods provided by the edge function in the smoothed image G.

Which one s works best? Try also after a Gaussian filter. Use the returned value for the gradient threshold to help you calibrate your edge detection. Kmeans is an iterative clustering technique that separates a data set into K mutually exclusive clusters, such that members within a cluster are closer to each other and to the cluster centroid its mean than to members and centroid of any other cluster.

When applied to perform image segmentation, Kmeans partitions the image into regions of similar intensities. It works very well for images with close to homogeneous regions. Is there a better way? But the first doesn't return the x and y coordinates of the contour. The second function requires a seed point which i cannot provide.

An example of the image is shown below. As another approach might be that bwperim performs this operations internally boundaries of a binary image can be obtained by calculating the difference between the dilated and the eroded image. Here, however, the boundary is thicker than using bwperim , as the pixels are masked in both inside and outside of the object. I'm surprised you didn't see bwperim. Did you not try bwperim? This finds the perimeter pixels of all closed objects that are white in a binary image.

Using your image directly from StackOverflow:. By posting your answer, you agree to the privacy policy and terms of service. Email Sign Up or sign in with Google. Compute contour of a binary image using matlab Ask Question. But if you already have a binary image, why can't you follow the steps outlined in this Matlab tutorial? It requires a seed point "Determine the row and column coordinates of a pixel on the border of the object you want to trace bwboundary uses this point as the starting location for the boundary tracing.