This menu groups operations which filter images, or
which are filters in the photoshop sense.
- This menu has several standard
convolution operations (blur, sharpen, edge detect,
etc.), plus the option to convolve with a custom
Two menu items are slightly more complicated.
Unsharp Mask transforms to CIE LAB colour
space, then sharpens just the L band with a cored
unsharp filter. The Tasks / Print menu has
a version of this filter tuned for typical inkjet
Custom Blur builds and applies a square or
gaussian convolution kernel for you based on a
- A preset median filter, and a custom rank filter
that lets you specify window size and rank.
The Image Rank item does pixel-wise ranking
of a set of images.
- These menu items implement basic
morphological operations. Images are zero for
background and non-zero (usually 255) for object.
Matricies are shown as 0, 1 and * for background,
object and don’t-care.
The Threshold item does a simple level
threshold. Use the Math / Relational menu to
construct more complex image binarisations. Use
Math / Boolean to combine morphologies.
The first half of the menu lists simple erode
and dilate operations, 4- and 8-way connected.
The second half contains several useful compound
See also Histogram / Find Profile for
something that can search an image for object
edges. And MathStatistics / Edges can
count the number of edges across and down an
- A selection of ideal, Gaussian and
Butterworth Fourier space filters.
You can make other mask shapes yourself using the
Image / Make Patterns menus, then apply
them using Math / Fourier. You can also use
the image paintbox to directly paint out peaks in
a fourier-space image before transforming back to
- A selection of simple image enhancement
filters. Statistical Difference passes a
window over an image and tries to match the
region statistics at each point to a target mean and
- Place a small image at
every possible position in a big image and
calculate the correlation at each position. Simple
Difference is the much faster unnormalised
- VIPS includes a copy of the
CImg library and you can use two useful
CImg operations from this menu: denoising and
- A selection of tools
for adjusting the brightness of an image across it’s
surface. Useful for correcting lighting problems.
- Blend two objects together using either a third
object to control the blend at each point, or a slider
to set all points together. You can blend almost
anything with anything.
One useful version is to use a text image (see
Image / Make Patterns / Text) to blend
between two colours (see Colour / New).
Along Line does a left/right or top/bottom fade
between two images.
- Make a colour overlay of two monochrome
images. Useful with Image / Transform / for
testing image superposition.
- Use a colour image to tint a monochrome
image. Useful in conjunction with Image /
Transform / .
- Look at either the bits or the bands of an
Photographic Negative and friends
- A small
selection of simple, faintly photoshop-style filters.