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Captions
Figure 1
An example of a basic Null transform using ImageFX 2.0's enhanced Color
Transform tool, which allows the user to create a custom correction curve by using
either freehand drawing, line segments or splines. These custom curves can be
saved and loaded for future use. Excellent!
Figure 2
A Threshold transform forces pixel values to either a minimum or maximum value
depending on where they lie relative to some cut-off point. This transform
drastically reduces the number of colors or brightness levels to a very few.
Figure 3
In a Solarization transform, all the darkest pixels below a certain brightness value
are negated, while keeping intact all hues above the cut-off point with a Null-like
transform.
Figure 4
Sawtooth transforms, commonly used in the medical imaging, divide successive
regions into bands that range from minimum to maximum intensity levels. This
makes it possible to visually distinguish certain regions for more detailed analysis.
Figure 5
This DoubleGamma transform created by the author has an aesthetically pleasing
effect on some images. Essentially, darker pixels are made slightly darker without
getting clipped because of the gamma-shaped curve. Similarly, lighter regions
above the midway point are brightened without the undesirable clipping that
occurs with Brightness curves. The result of this transform has an effect similar to
a carefully expanded histographic equalization filter.
Figures 6
This is a histogram analysis performed on several versions of an image. Each
version shows the number of colors available in the image and its correspondingly
less detailed, and hence useful, histogram.
Figure 7
Using ImageFX's "Hist" hook, this is a series of histograms performed on the five
transforms seen in Figures 1-5.
Figure 8
The original, scanned wood texture is shown at top with its corresponding
histogram produced by ADPro's Intensity Range operator. The middle image shows
the dramatic improvement of overall contrast by expanding the distribution of
pixel values on both sides of the spectrum with the histogram equalization power
of the Intensity Range operator. Finally, the bottom image is the result of using
ADPro's less flexible "Hist_Equalization" operator. Because its effect differs slightly
from that of "Intensity Range", this operator's nomenclature may confuse those
already familiar with ImageFX's Histogram Equalization filter, whose function is
identical to ADPro's Intensity Range operator.
Figure 9
Here, the dominant regions of the image are displayed nicely in a histogram: A)
the darker facial area B) the medium bright background C) the very light portions
of the baseball cap. Adjusting the histogram equalization by surrounding the
darker facial area (A) with the range limiters, we can increase the brightness and
enhance the contrast of just that area for a much better tonal result in the face.
Note that the other two unimportant regions (B) and (C) get clipped to white.
Figure 10
By emphasizing different components in a Color_To_Gray operator, subtley
different results are produced in the final greyscale image.
Figure 11
Two examples of ImageFX's False Color filter. The image is remapped to these
custom palettes according the luminance values of the original pixels. Darker
pixels remap to the colors in the first available wells of the palette and vica versa.
The palettes chosen are "3D" and "BGR," respectively.