Image Enhancements
You have your choice of these image enhancements:
-
- Spiff
- enhances the intensity differences between the lighter and
darker elements of the image.
- Dull
- reduces the intensity differences between the lighter and
darker elements of the image.
- Equalize
- perform histogram equalization on the image.
- Normalize
- transform image to span the full range of color values.
- Negate
- replace very pixel with its complementary color (white becomes
black, yellow becomes blue, etc.).
- Hue
- vary the percent hue of the image (0-200%).
- Saturation
- vary the percent saturation of the image (0-200%).
- Brightness
- vary the percent brightness of the image. Reasonable values
extend from 50 (darker) to 150 (brighter).
- Gamma
- level of gamma correction. The same color image displayed on
two different workstations may look different due to differences in
the display monitor. Use gamma correction to adjust for this color
difference. Reasonable values extend from 0.8 to 2.3.
You can apply separate gamma values to the red, green, and blue
channels of the image with a gamma value list delineated with
slashes (e.g. 1.7/2.3/1.2).
- Level
- adjust the level of image contrast. Give three point values
delineated with slashes: black, mid, and white (e.g. 10,1.0,65000).
The white and black points range from 0 to MaxRGB and mid ranges
from 0 to 10.
- sigmoidal-contrast
- sigmoidal non-lineraity contrast control. Give two values contrast and midpoint. Increase the contrast of the image using a sigmoidal transfer function without saturating highlights or shadows. Contrast indicates how much to increase the contrast (0 is none; 3 is typical; 20 is a lot); mid-point indicates where midtones fall in the resultant image (0 is white; 50% is middle-gray; 100% is black). A good starting point is 3x50%.