User Guide

Chapter 10: Visualization And Analysis
Scientific filters
Canvas features scientific filters that can be used to analyze 8-bit, 16-bit, and floating point (32-bit)
images. See "Available filters and adjustment commands" on page 749 to verify which scientific filter
is available for the various image types.
To access the Scientific filters:
Choose Image | Filter | Scientific.
Arithmetic
The Arithmetic Filter contains commands that add (subtract, multiply, etc.) a value to each pixel in
the active image or selection. When the result value is above or below the legal range of the image's
data type, the value is reset to the maximum/minimum value.
To apply an Arithmetic filter:
1. Select the image object (or part of it with a Marquee or Lasso tool) or place it in edit mode.
2. Open the Operation menu to choose a command.
Select the Preview check box so you can see the result before clicking OK.
3. Enter a value in the Value numeric field.
4. Click OK.
The Operation menu contains the following commands:
Operation Explanation
Add Adds a value to the image. With 8-bit images, results greater than 255
are set to 255.
Subtract Subtracts a value from the image. With 8-bit and 16-bit images, results
less than 0 are set to 0.
Multiply Multiplies the image by the specified real value. With 8-bit images,
results greater than 255 are set to 255. With 16-bit signed images,
results greater than 65,535 are set to 65,535.
Divide Divides the image by the specified real value. Attempts to divide by zero
will be ignored.
Minimum Pixels in the image with a value less than the specified value are replaced
by the value.
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