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5.4 Histogram
This menu groups operations for finding and transforming image histograms.
nip2 represents histograms and lookup tables as images with Type
set to Histogram. Histograms may have pixels in any format and any
number of bands. You can only find histograms of unsigned 8- and 16-bit
images.
- New Histogram
- This makes a new ramp histogram. A set of sliders let you adjust the
shape. Use Map Histogram to apply your ramp to an image.
- Find Histogram
- A one dimensional histogram treats each band as an independent
variable. An
-dimensional histogram treats each pixel as a vector of
elements, where
is the number of bands in the image.
- Map Histogram
- Looks up each pixel in the input in the histogram and send the found
value to the output.
- Histogram Equalisation
- Find the global or locally histogram equalised image.
- Cumulative Histogram
- Use this and friends to calculate a cumulative histogram, normalise a
histogram and match two histograms.
- Find Profile
- Searches from the edges of an image for the first non-zero pixel and
returns a profile histogram.
Mark a guide on an image (drag from the
image rulers, or click File / New / Guide) and click
Slice Image to make a histogram which is a horizontal or vertical
slice through an image.
Next: 5.5 Image
Up: 5. Image processing menus
Previous: 5.3 Format
Contents
John Cupitt
2004-12-20