Color Calibration
The Color Calibration module provides a way to better align the colors
within an image to that of reality. This is accomplished by including
a standardized color chart within the image that can be used as a color
reference. By aligning the image color chart with the known color chart
the rest of the image's pixels can be moved towards the calibrated colors.
Note that images that are severly out of color alignment will cause
pixelated artifacts as the module tries to move pixel colors to
aligned colors. It is always better to configure your hardware
imaging devices to produce the best colors possible and thereafter
attempt software correction.
Interface
Instructions
1. Green, Cyan, Purple, Blue squares - drag the squares to align with the color chart
that should be present in the image.
2. Coordinates - Use the text boxes to refine the coordinates
3. Color Samples - The Color Samples are the known colors that are used to calibrate
against. The module is configured for the Macbeth color chart by default. If you are
using a different calibration chart you can press the Resample button to sample the
colors from the new chart (once aligned) and then use either the edit button or double
click on the color to change its value.
4. Soft vs Harsh Option - Select how strong the alignment should be. Selecting Soft will
align the source image to the calibrated color with respect to intensity and contrast
which will help align the colors but not radically change the image colors.
Note that on harsh calibration flat areas will appear more pixelated
5. Sample Size - Specify the size of the sample area. The sample area should include only
those pixels that specify a specific color and are average to produce the alignment color.
If the sample size is too large then non-color chart colors may influence the calibration
so be sure the squares fit in the chart area correctly.
6. Horizontal & Vertical Samples - Specify the appropriate number of samples that your
color chart contains by adjusting the horizontal and vertical sample number. Note that when
adjusting these values the number of squares and sample colors will change to reflect
the new dimensions.
Example
| Source | Soft Calibration |
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| Harsh Calibration | Target |
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See Also
Color Balance
Align Histogram
For more information
The Macbeth Color Checker
Wikipedia - Color Chart
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