How to detect larger corners in an image?
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Hi,
I am having trouble understanding how to use "corner". An image of my problem can be found here:
Basically, I'm picking up lots of speckles in my photo, but not a lot of what I'd consider to be corners. Based on my understanding of how corner detection algorithms work, I think I'd like the area used to compare the pixel to it's neighbors to be larger (but I could be wrong). How is this accomplished? Thanks in advance!
-Jen
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Accepted Answer
Anand
on 20 Jun 2013
I'd suggest trying to play around with the 'FilterCoefficients' and 'QualityLevel' parameters.
Increasing the kernel width and smoothing on the kernel has the effect of blurring out corners at smaller scales.
Increasing 'QualityLevel' would mean the minimum corner strength increases.
Post the actual image if that doesn't work.
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Image Analyst
on 20 Jun 2013
Try adjusting some of the optional input parameters of corner(). If that doesn't work, filter out the bad ones with bwarea(), or prefilter the image by thresholding it.
Second option is to use hough() or houghlines() and look for where lines intersect.
Third option is to use bwboundaries() and find the kinks in the boundary using the FAQ: http://matlab.wikia.com/wiki/FAQ#How_do_I_find_.22kinks.22_in_a_curve.3F
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Image Analyst
on 20 Jun 2013
Your first statement is not true. You get the lines then you have to figure out where lines that are perpendicular to each other intersect. The hough is just the first step and the intersection-finding is the second step.
I'm not sure why you want to use grayscale images and edge() (which I did not recommend), rather than binary images, bwboundaries(), and the FAQ code for finding kinks like I recommended.
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