This module enhances the edges (gradients) in a grayscale image. All methods other than Canny produce a grayscale image that can be used in an

What did you call the image in which you want to enhance the edges?

What do you want to call the image with edges enhanced?

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Select *No* to manually enter the threshold value.

The upper cutoff for Canny edges. All Sobel-transformed pixels with this value or higher will be marked as an edge. You can enter a threshold between 0 and 1.

This threshold adjustment factor is a multiplier that is applied to both the lower and upper Canny thresholds if they are calculated automatically. An adjustment factor of 1 indicates no adjustment. The adjustment factor has no effect on any threshhold entered manually entered.

There are several methods that can be used to enhance edges:

*Sobel:*Finds edges using the Sobel approximation to the derivative. The Sobel method derives a horizontal and vertical gradient measure and returns the square-root of the sum of the two squared signals.*Prewitt:*Finds edges using the Prewitt approximation to the derivative. It returns edges at those points where the gradient of the image is maximum.*Roberts:*Finds edges using the Roberts approximation to the derivative. The Roberts method looks for gradients in the diagonal and anti-diagonal directions and returns the square-root of the sum of the two squared signals. This method is fast, but it creates diagonal artifacts that may need to be removed by smoothing.*LoG:*Applies a Laplacian of Gaussian filter to the image and finds zero crossings.*Canny:*Finds edges by looking for local maxima of the gradient of the image. The gradient is calculated using the derivative of a Gaussian filter. The method uses two thresholds to detect strong and weak edges, and includes the weak edges in the output only if they are connected to strong edges. This method is therefore less likely than the others to be fooled by noise, and more likely to detect true weak edges.

The direction of the edges are you are identifying in the image (predominantly horizontal, predominantly vertical, or both).

Select

Select *No* to manually enter the low threshold value.

Enter the soft threshold cutoff for the Canny method. The Canny method will mark all Sobel-transformed pixels with values below this threshold as not being edges.