Laplace filter

Use the Process > Edge Detection Filters > Laplace... to extract intensity borders and lines in the image. The Laplace filters belong to the so called edge detection filters, i.e., filters that you can use to only select the contours in an image and ignore everything else.

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Parameters for the Laplace filter

Should a weaker emphasis of the edges be necessary, simply select the Settings > Laplace 1 option; if a stronger emphasis of the edges is necessary, select the Settings > Laplace 2 option.

Exactly what happens?

Laplace 1

The Laplace I filter differentiates the image into X- and Y-directions. In doing so, the edges and smaller structures in the image will be highlighted. The Laplace filter, however, amplifies noise just as much as it enhances genuine image information.

Filter matrix

Laplace 2

The Laplace II filter differentiates the image into X- and Y-directions, as well as into diagonals. In doing so, the edges and smaller structures are highlighted in every direction in the image. The Laplace filter, however, amplifies noise just as much as it enhances genuine image information.

Filter matrix

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