Module: EnhanceEdges

Enhance Edges enhances or identifies edges in an image, which can improve object identification or other downstream image processing.
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 Identify module or thresholded using the ApplyThreshold module to produce a binary (black/white) mask of edges. The Canny algorithm produces a binary (black/white) mask image consisting of the edge pixels.

Settings:

Select the input image

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

Name the output image

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

Automatically calculate the threshold?

(Used only with the Canny option and automatic thresholding)
Select Yes to automatically calculate the threshold using a three-category Otsu algorithm performed on the Sobel transform of the image.

Select No to manually enter the threshold value.

Absolute threshold

(Used only with the Canny option and manual thresholding)
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.

Threshold adjustment factor

(Used only with the Canny option and automatic thresholding)
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.

Select an edge-finding method

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

Select edge direction to enhance

(Used only with Prewitt and Sobel methods)
The direction of the edges are you are identifying in the image (predominantly horizontal, predominantly vertical, or both).

Calculate value for low threshold automatically?

(Used only with the Canny option and automatic thresholding)
Select Yes to automatically calculate the low / soft threshold cutoff for the Canny method.

Select No to manually enter the low threshold value.

Low threshold value

(Used only with the Canny option and manual thresholding)
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.