Smooth segmented region line in an image

Hi i have performed segmentation on an image to segment the black area at the top left hand corner seen in the first image below. I now need to smooth this line by finding four points along this segmented area, and then using the straight line equation. The resulting image should look like the second image. Can anyone help me the first part, finding four points along the segemented area?

Any help would be reallyyyy appreciated!

Thanks!

Answer 1

[Image Analyst]

Assuming, like you said, that you have segmented out the upper left black part all by itself. Let's call that "binaryImage". Then you can just run bwboundaries to get the coordinates.

boundaries = bwboundaries(binaryImage);
x = bwboundaries{1}(:,1);  % Think this is the right syntax but not sure.
y = bwboundaries{1}(:,2);  % Think this is the right syntax but not sure.

Then find any x values that are 1 and remove those coordinates. Then find any y values that are 1 and remove those points too. Now you have just the ragged points. Pass them into polyfit

coefficients = polyfit(x, y, 1);

Now find out where the line intersects the y=1 and x=1 edges. Then construct a triangle from the 3 coordinates and use poly2mask to create a binary image.

mask = poly2mask(triX, tryY, rows, columns);

Then blacken above the line my masking

newBinaryImage = binaryImage;
newBinaryImage(mask) = false;

However about half of the ragged black part will be below the fitted line and you'll need to fill those in. This can be done by finding them by ANDing your original image with the inverse of the triangle mask.

raggedSpots = binaryImage & ~mask;

Now fill them in in the newBinaryImage image.

newBinaryImage(raggedSpots) = true;

This was totally just off the top of my head and untested. There's still a little for you to do, I'm sure. Come back with your code and original image if you need me to debug it for you. Good luck.

[Ciara]

Thank you! I will give this a try!!