home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Amiga Mag HDD Backup
/
Amiga Mag HDD Backup.zip
/
Amiga Mag HDD Backup
/
Alexander.img.bin
/
Alexander.img
/
9.12
/
Frawley⁄Digital FX14
/
Captions.ascii
next >
Wrap
Text File
|
1983-05-04
|
2KB
|
38 lines
Captions
Figures 1A-1B
A) A graphical representation of a Null 1-to-1 pixel transform -- output equals input. B) The
original image of ``Jordan'' to be used for later transforms shows a good range of values to work
with.
Figures 2A-2B
A) A Negative or Inverse transformation curve. B) The result of taking the Negative of an image
in ADPro.
Figures 3A-3C
A) A graphical representation of increased Brightness. Note the region in the upper value range
which gets clipped. All detail which was in this range is lost. B) The effect of adding brightness
to an image. C) The result of decreased brightness. Here, any detail in the lowest ranges
disappears because of clipping.
Figures 4A-4C
A) A graph of the Contrast transform. With an increased slope, detail within the unclipped ranges
is gained because for any range of input intensities, the corresponding output values span a larger
range. However, clipping occurs at the extremes. B) By increasing the contrast, the skin tones
look better at the expense of the darker background and hair areas. C) On the contrary,
decreasing the contrast in the image tends to `wash out' the overall detail.
Figures 5A-5C
A) A non-linear Gamma transform effectively allows the brightness to be increased or decreased
without the problem of clipping occuring. Note also that different regions of the curve produce
increased or decreased contrast. B) Unlike simply increasing the brightness (see Figure 3B), a
gamma transform maintains the lower end of the luminance spectrum while also preventing
clipping in the upper regions. C) Similar advantages occur for a gamma correction with a
gamma factor greater than 1, producing a downward-bowed curve.
Figures 6A-6B
A) A Posterization or Quantization transform produces a stair-step output function. Input
intensities lying within a certain range all get mapped to one discrete output value, effectively
reducing the number of colors within the image. B) Posterization applied to the image using
ImageFX's Posterize... operator set to a value of 5.