8.3. Rand

8.3.1. Overzicht

Afbeelding 17.171. Applying example for the Edge filter

Applying example for the Edge filter

Originele afbeelding

Applying example for the Edge filter

Filter applied


This filter detects edges in an image using the method selected in Algorithm.

8.3.2. Activeren van het filter

Dit filter is te vinden in het hoofdmenu onder FiltersRandenRand….

8.3.3. Opties

Afbeelding 17.172. Opties filter Rand

Opties filter Rand

Voorinstellingen, Type invoer, Snijden, Mengopties, Voorbeeld, Filter samenvoegen, Voor/na
[Opmerking] Opmerking

Deze opties staan beschreven in Paragraaf 2, “Algemene eigenschappen”.

Algoritme

The algorithm selected here, determines what method is used to detect edges. The following methods are available:

Sobel

This is an alternative version of the separate Sobel filter. Contrary to that filter, this one has no additional settings that can be adjusted. This is the default; an example is shown at the top of the page.

Prewitt-kompas

The Prewitt operator is a relatively fast algorithm, that can be relatively crude for high frequency variations in an image.

Algorithm set to Prewitt compass

Kleurverloop

When using the Gradient algoritm, edges are thinner, less contrasted and more blurred than Sobel.

Algorithm set to Gradient

Roberts

The Roberts algorithm will highlight changes in intensity in a diagonal direction. However, it suffers greatly from sensitivity to noise.

Algorithm set to Roberts

Differentiaal

This algorithm often causes edges to be less bright.

Algorithm set to Differential

Laplace

This is a different implementation of the Laplace filter, that gives different results.

Algorithm set to Laplace

Hoeveelheid

A low value results in a black, high-contrasted image with thin edges. A high value results in thick edges with low contrast and many colors in dark areas.

Randgedrag

This determines where the edge detector will get adjoining pixels for its calculations when it is working on the image boundaries. This setting will only affect the boundaries of the result (if any). Clamp is the default and the best choice in general.