img sharpen

Sharpens an image. By default convolves the image with a Gaussian operator with the given --radius and --sigma.

--radius <num>
The radius of the Gaussian blur, not including the center pixel (default: 1).
--sigma <num>
Weight to use for calculating the pixels contribution to the final colour (default: 1.0).
Use the “unsharp” method. This blurs the original image, and subtracts this blurred image from the original.
--amount <num>
Amount to sharpen by (default: 1.0) (--unsharp only).
--threshold <num>
Fraction difference required to apply sharpen (default: 0.05) (--unsharp only).