By using this method, you can increase the impression of sharpness in an image and consequently obtain an image which shows structures with more contrast. The function enhances contrast especially for smaller structures.

Parameter

Description

Strength

Enter the strength of the Unsharp Masking using the slider or spin box/input field. The higher the value selected, the greater the extent to which small structures are enhanced.

Sigma

Adjusts the sigma value derived from Gauss filtering. Reduces noise in an image. Each pixel is replaced by a weighted average of its neighbors. The neighboring pixels are weighted in accordance with a two-dimensional Gauss bell curve.

Color Mode

Select the desired color mode from the drop-down list.

-

RGB

Calculates the sharpness for each color channel individually. The color saturation and the color of structures may be changed, and color noise may occur.

-

Luminance

Only calculates the sharpness on the basis of the brightness signal detected. This mode does not show any color noise and changes the color saturation accordingly.

Threshold Mode

Here you can select a setting from the drop-down list for calculating the boundary between the sharpened image regions.

It is only effective if the value for the Threshold Low parameter is not equal to 0 or the value for the Threshold High parameter is not equal to 100.

-

None

No adjustment takes place.

-

Binary

The transition follows the threshold values.

-

Linear

Calculates a linear course.

Threshold Low

Enter the lower threshold value using the slider or spin box/input field. This determines the lower limit from which existing contrast structures are changed.

Threshold High

Enter the upper threshold value using the slider or spin box/input field. This prevents structures in the image already featuring high contrast from being further enhanced unnecessarily.

Clip to Valid Bits

Activated: The value range of the gray/color values of the output image is adjusted to the value range of the input image.