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HoughLine parameter

asked 2017-01-26 02:07:53 -0500

testo gravatar image

I want to use houghline to detect lines in image. I read the concept of houghline in openCV website

According to this api call HoughLines(InputArray image, OutputArray lines, double rho, double theta, int threshold, double srn=0, double stn=0 ) and this explanation rho – Distance resolution of the accumulator in pixels. theta – Angle resolution of the accumulator in radians.

I still conduse what is rho and theta in parameter do. Isn't the result of houghLines, OutputArray lines, defined in term of rho, theta?

Could you explain a purpose of rho and theta in parameter?

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answered 2017-01-26 03:25:32 -0500

00Zetti gravatar image

In short: As you should know, the Houghtransformation maps your input image from spatial domain into the Houghspace. You do this with a certain resolution(rho, theta), let's say your accuracy: e.g. you can map your pixels from spatial domain into Houghspace with a stepsize, that defines how often you should change the angle to observe and map the pixels into Houghspace. The smaller the stepsize the more dense your Houghspace will become. Hope that helps you to understand the parameters and the transformation.

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Thank you very much. That answer my question.

testo gravatar imagetesto ( 2017-01-26 23:33:24 -0500 )edit

answered 2017-01-26 02:29:30 -0500

LBerger gravatar image

there is a good tutorial here

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Asked: 2017-01-26 02:07:53 -0500

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Last updated: Jan 26 '17