Highpass

Menu:   Processing > Filters… > Edges->Highpass

Script:   highpass

Use this function to extract high frequency components from an image. The filter works by subtracting the result of the Lowpass operator from the original image. The cutoff frequency is determined by the size of the filter kernel. If an overflow occurs, the result is clipped to the minimum or maximum pixel value for the given image type.

If you choose this command, the following options will become available:

Input

Displays the input image frame number. If you want to process another image, type or select the corresponding value.

Output

Displays the number of the frame in which the output image will be created. Depending on the Preferences. ImageWarp will set it either to the first available value or to the Input frame number. Type or select another value if you want the output image to be created in a different frame.

Preview

Select this check box to watch the Preview of the output image.

Sizex

Lets you adjust the width of the filter kernel which determines the horizontal cutoff frequency. The larger the width is, the smaller cutoff frequency will be. This value must not exceed 2*Overscan+1. See Preferences for more details.

Sizey

Lets you adjust the height of the filter kernel which determines the vertical cutoff frequency. The larger the height is, the smaller cutoff frequency will be. This value must not exceed 2*Overscan+1.

Factor

Defines the amplification factor for high frequencies. The difference between the original and lowpass image is multiplied by this value.

Offset

Defines the offset of intensity in the output image. Increasing this value will prevent the negative values from clipping to the black level.

Preview