what is dp parameter in Hough Circle detection on opencv.

dp parameter is about resolution of voting space.
dp is larger, voting resolution is small compare to image size.
so dp is larger, circle detection accuracy is not exact.
but dp is smaller, voting resolution is higher and circle detection is more accurate but that sensitive with noise ex)other edge..
I increase dp from 1 to 5 step by 0.1..

refer to this source code on here.


< gist code >

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and result image.

....

and other reference.
opencv org

• http://docs.opencv.org/2.4/modules/imgproc/doc/feature_detection.html?highlight=houghcircles#houghcircles

stack overflow

• http://stackoverflow.com/questions/34706092/how-exactly-does-dp-parameter-in-cvhoughcircles-work
• http://stackoverflow.com/questions/33544411/in-the-circle-hough-transform-what-is-the-inverse-ratio-of-accumulator-resoluti/33545904#33545904

python opencv tutorial

• http://www.pyimagesearch.com/2014/07/21/detecting-circles-images-using-opencv-hough-circles/

#tags
GaussianBlur, HoughCircles, CV_HOUGH_GRADIENT,