Hough crop

The Hough crop operation is used to select a region of the Hough transform. The HoughMap is cropped in \(\rho\) to the specified value. In other words, the map is cropped along its height. This operation is particular useful to remove the edges of the Hough transform which could be interpreted as false peaks.

../../../../../_images/houghcrop_before.png

Original Hough map

The user was three options when selecting the cropping \(\rho\) value.

  1. Crop to a specified \(\rho\). Any value between 0 and the maximum \(\rho\) of the Hough map is allowed. This option corresponds to entering a positive value in the combo box.
../../../../../_images/houghcrop_140.png

Crop with a rho = 140

  1. Crop to a value of \(\rho\) equals to the radius of the Mask disc operation. This option is automatically selected if the entered value in the combo box is equal to -1.
../../../../../_images/houghcrop_127.png

Crop with a rho = -1

  1. Crop to a value of \(\rho\) equals to the radius of the Mask disc operation minus a specified value. This is equivalent to having a disk mask with a smaller radius. For this option, the user must enter a negative value less than -1. For example, a value of -2 will correspond to \(\rho\) equals to the disk mask operation’s radius minus one pixel.
../../../../../_images/houghcrop_90.png

Crop with a rho = -38