MLUnsold Digital Imaging

Contrast Enhance & High Pass Sharpen Using the Frequency Filter

Image contrast and sharpness can be increased using the Smooth Sharpen | Frequency Filter. The High Pass or Band Pass option with Normalize checked is used to create a normalized edge image. Soft light blend mode and opacity are then set on the Process History window to blend the normalized edge image with the initial image.

Initial image of M1 before contrast and sharpen enhancement.

Normalized edge image created by applying the Frequency filter with High Pass and Normalize options. The Process History window is set by default to normal blend mode and 100% opacity. So the normalized edge image completely replaces the initial image.

Soft light blend mode is set and opacity adjusted on the Process History window to blend the normalized edge image and initial image.

The Band Pass with Normalize option offers greater control of creating the normalized edge image. The cutoff, decay, and width parameters are adjusted to select a wide or narrow range of frequencies.

Initial M1 image is shown on the left. Normalized band pass M1 image is shown on the right.

Initial image of M1 before contrast and sharpen enhancement.

Normalized edge image created by applying the Frequency filter with High Pass and Normalize options. The Process History window is set by default to normal blend mode and 100% opacity. So the normalized edge image completely replaces the initial image.

Soft light blend mode is set and opacity adjusted on the Process History window to blend the normalized edge image and initial image.

The Band Pass with Normalize option offers greater control of creating the normalized edge image. The cutoff, decay, and width parameters are adjusted to select a wide or narrow range of frequencies.

Initial M1 image is shown on the left. Normalized band pass M1 image is shown on the right.