This menu groups operations which apply only to
- Makes a new image. Region on Image
makes a new region, arrow, guide or mark on an
image. It’s usually easier to open a viewer on an
image and Ctrl-drag.
Convert to Image
- Try to make an image out of
- Switch between the various precisions.
- Try to change or examine the image header in
- This caches an image in RAM. Use this to save
the results of a long computation.
- Various tools that change the levels in an
image. Tone Curve is the only complex one: it
lets you adjust the image levels with a set of sliders.
- Various tools that change the geometry of
To use Rotate / Straighten, mark an
arrow on an image (Ctrl-drag up and left in an
image view window) along a near-horizontal or
near-vertical edge. When you click on Rotate
/ Straighten, nip2 will rotate the image by
the smallest amount that makes that edge exactly
horizontal or vertical.
Linear Match takes two images and rotates
and scales the second so that the images can
be superimposed. Drag the tie-=points to mark
common features. Use Filter / Overlay or
Filter / Colourize to actually superimpose
Rubber Sheet is useful for fixing things like
lens distortion. You give Find two images, a
reference and a distorted version of that reference,
and it automatically finds a transform which will
map the distorted image back on to the reference
image. Use Apply to apply the discovered
transform to another image.
- Extract/insert/delete image bands. Use To
Dimension to change image bands into a
horizontal or vertical dimension. Use To Bands
to compress the horizontal or vertical dimension
into bands (small images only!).
- Crops an image. It’s often easier to drag out a
region. This menu item is only really useful for
cropping large groups of images.
- This takes two images and pastes the smaller
into the centre of the larger. The two images have
to have the same number of bands. If you open an
image viewer on the large image, you’ll see an area
which you can drag around to set the exact insert
- Draw elipses and polygons on an image.
Useful for selecting defined areas.
- Use to join two images together bandwise,
left/right or up/down. Array joins a list of lists of
images together into a single large image.
- Repeat an image horizontally and vertically to
make a larger image, or chop an image into a set of
- These items all make useful images for
you, from checkerboards to gaussian masks. XY
Image is the most useful: you can use it to build
- These items make a variety of useful
testcharts for evaluating spatial response and