Menu rFilters
Monochrome and Color Filters

Blur

Menu: rFilters > Blur

Description: This filter produces image blur effect, giving the impression that the image is slightly "out of focus". Blur filtration reduces image clearness, but makes image areas with texture fills more even. This procedure can have a positive effect on further binarization or image color separation.

See also: Quick Start "Editing color images"

UnSharp Mask

Menu: rFilters > UnSharp Mask

Description: This filter seeks color transition boundaries in the image and improves their sharpness.
The filter modifies pixel contrast on color transition boundaries, producing an overall increase of image sharpness. This filter can be used for correction of images that became blurred after interpolation, for example, after such operations as scale, resolution modification or calibration.

See also: Quick Start "Editing color images"

Median

Menu: rFilters > Median

Description: Median filtration reduces an image noise, by analyzing all pixels within the specified radius and giving the central pixel the averaged value of the reviewed pixel characteristics. As a result, the extremes of pixel color and brightness are depressed and the image looks slightly blurred.

See also: Quick Start "Editing color images"

Speckle Remover

Menu: rFilters > Speckle Remover

Description: The Speckle Remover filter removes raster objects (isolated pixel groups) that are smaller than those of the specified value. This filter can automatically estimate the speckle size in the image.
The filter can be used after such procedures as binarization and layering to remove low-sized raster objects in the obtained monochrome images' layers.

Monochrome raster fragment, obtained after binarization

After speckle removing

See also: Quick Start "Enhancing Scanned Images"

See also: Tutorial "Enhancing Raster Images"

Hole Remover

Menu: rFilters > Hole Remover

Description: This filter removes low-sized holes in raster objects. Only holes with size less than the specified value are removed. The filter can automatically estimate hole size on image objects.
The filter can be used after such procedures as binarization and layering to fill undesirable holes in raster images.

Original image

After hole removing

See also: Quick Start "Enhancing Scanned Images"

See also: Tutorial "Correction and Binarization of Color Images"

Inversion

Menu: Filters > Inversion

Description: The Inversion filter reverses the color of a monochrome image for each dot. Background dots become image dots; image dots become background dots. The following illustration shows the inversion filtration result. This filter applies only to entire image.

Effect of inversion

See also: Quick Start "Enhancing Scanned Images"

Smoothing

Menu: Filters > Smoothing

Description: This filter smoothes raster object edges, fills inner background droplets, and partially removes raster speckles.

Original image fragment

After smoothing

See also: Quick Start "Enhancing Scanned Images"

See also: Tutorial "Enhancing Raster Images", "Correction and Binarization of Color Images"

Thinning

Menu: Filters > Thinning

Description: The Thinning filter makes raster fragments thinner by a specified number of pixels in specified directions - horizontal, vertical, and diagonal. This filter has a supplementary parameter that allows thinning raster objects up to skeleton (only pixels in the middle are left).

After thinning up to skeleton

See also: Quick Start "Enhancing Scanned Images"

See also: Tutorial "Correction and Binarization of Color Images"

Thickening

Menu: Filters > Thickening

Description: The Thickening filter makes raster objects thicker by specified number of pixels. You can choose a combination of thickening directions: horizontal, vertical, or horizontal, vertical and diagonal.

Original image

Thickening filtration in all directions

See also: Quick Start "Enhancing Scanned Images"

Contour...

Menu: Filters > Contour > 4-coupling; Filters > Contour > 8-coupling

Description: Contour filters convert filled raster areas of the image to one-pixel outlines. The 4-coupling filter creates 4-coupling contour; the 8-coupling filter creates 8-coupling contour. In the 4-coupling filter the contiguous areas can only be coupled with their sides; the 8-coupling filter analyses corner contiguity, so such images look thinner.

Fragments of outlines, obtained after 4-coupling and 8-coupling filtration

See also: Quick Start "Enhancing Scanned Images"

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