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TUTORIAL.DOC
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1990-10-06
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I. COLORIZATION: Colorizing Grey Images
False Colorization is the process by which you are now viewing
Black & White movie classics in living color. You can do the
same thing, particularly if you own a digitizer that supports
grey scales. I have selected 16 gray shades as the main focus of
VGACAD's support, primarily since it is aimed at the low-end
market. If you want to colorize gray images with more that 16
shades use the ColorBAR (CBAR) option to change the range of
local colors.
Let us colorize one of the famous GIF pics in BBSs - MONROE.GIF
(which is being distributed with Michael Vigneau's VGAGIF in
VGADEMO.arc).
MONROE.GIF is a 16 grey-level picture with colors 0 to 15
containing the entire grey scale. Run VGACAP, then view the
picture with any GIF viewing utility; capture the picture then
load the screen and palette in VGACAD. The first thing to do is
to increase the number of grey scale elements. From the ImgP
(Image Processing) menu:
1) Convert (CNVT) the picture into the "Stretched 64" format.
This will give you the maximum range of grey levels although
the picture will remain unchanged.
2) Next BLUR the picture with a Threshold "Minimum =12"; this
will smoothen the picture yet keep most of the edge detail.
The smoothing will introduce intermediate grey scale values
making your picture richer. Notice the "salt and pepper",
random noise; these are the edges or "spikes" that were not
"blurred" to keep details.
3) You can remove those spikes with the Median Threshold
Filter, by increasing the value of BLUR to "Minimum=256".
You can, also, zoom into each area with "spikes" and blur
individual pixels with the HAZE function in the ZOOM Menu.
Using the Zoom Menu will take more time but a significant
amount of detail will be retained.
You have numerous combinations of image procesing techniques
at your disposal. You can use the CONTrast Enhancement
function, or EDGE Detection functions to boost details or
try different settings with the BLUR function to achieve
different effects; the HAZE, LITE, DARK and BLEND processes
can also be used on selected areas or pixels (from the Zoom
Menu); you have to experiment to get the optimal quality
from your grey image.
4) Convert (CNVT) the picture into a "Colors 32-63" format.
Now from the Files Menu, load the "GRAY32.PLT"; you will
notice that the picture remains untouched. You are now
ready to colorize your grey image.
Page ... 31
From the COLOR menu, select the CBAR option and change the range
to 32 by clicking the CBAR box until you see bands of 32 colors
on the upper and lower Colorbars. Click the AREA Colorization
option. Now, with the scroll arrows, set the lower Colorbar to
the 32 grey range; set the upper Colorbar to the flesh tones.
Select any area in your grey image; after releasing the LEFT
mouse button you will notice the entire area to be colorized with
the flesh tones of the upper Colorbar. Do this for all areas you
think will have that flesh tone; avoid the hair and background as
much as possible.
By now, most of your picture will have flesh tones and
overlapping areas in the hair and background. To edit each area,
use the ZOOM function in XColor mode; XColor will perform in the
same manner as AREA Colorization but on a pixel basis; remember
to keep the upper and lower Colorbars to reflect which range is
being replaced by the other - the lower Colorbar always replaces
the upper Colorbar. You can now use a "yellowish" Colorbar to
simulate blonde hair color. If you are not happy with any of the
hues, simply go into the Color Map and adjust any range until you
have colors best suited for your image.
Once you have colorized the hair, flesh areas and even the
background, you will notice that no matter how careful you are at
differentiating one colorized area from another (e.g., hair from
her face) there will be an area of high contrast between the
colorized areas. Click the MODE box and switch to PROCESS; use
the HAZE, LITE, DARK or BLEND functions to smooth out the
adjacent areas.
Now for the final touches, you can paint over the eyes, lips,
nails and any other detail in NORMAL mode or assign a new range
for these areas; each range uses 32 colors - limiting you to 8
color ranges. There are innumerable combinations to colorize your
grey picture. If you decided to convert your image processed
picture to 16 grey levels then you would have 16 color ranges to
play with. Experimentation is the only way to optimize the
results; after a few sessions you will be able to make startling
colorized images.
II. VSCRN TUTORIAL: Editing an 800x600x256 SVGA GIF
Let us assume you want to edit a corrupted version of a classic
800x600x256 GIF (ie., ZOE.GIF) in the "\GIF\SVGA" directory. You
want to remove some noise patterns from the lower-right corner
caused by a bad download (your lucky it even loads). You have a
PS/2 Model 50, a 30 Meg Hard Disk, and 1 Meg RAMDISK as Drive E.
1) From VGACAD's Main menu, click FILE. From the Files menu,
click VSCRN. You are in a sub-directory called "\VGACAD"
and will have to locate your picture file. As in the Files
menu, you click the word "Pathname" at the bottom of the
screen. You type the new path "\GIF\SVGA\".
Page ... 32
2) Now click the LIST box and all the GIF files in that
directory are listed. Having a large RAMDISK, click
"Pathname". Press <ret> without any input to retain the
PATH. Input the path of your RAMDISK at "VDSKpath" - which
is "E:\" <ret>.
3) Click the DCOD box and select "ZOE"; press the RIGHT mouse
button; "Filename: ZOE.GIF" appears at the lower left. Now,
click "OK"; the disk whirls; you see "Creating TEMP files."
4) You are back at VSCRN. Click the "iSCR vDSK" box then OK;
you see the center of the image slightly elongated (you are
still in a 5/6 aspect ratio). To correct the aspect ratio,
press "Esc" to get out of "iSCR" and PRESS [F2]-SIZE TO
TOGGLE ASPECT RATIO. The screen "squishes" about 20%. You
are now in a 320x200x256 mode with a 1:1 aspect ratio !
5) Now back to viewing; click "iSCR" then OK and try out all
the cursor keys. Press [F1] for HELP. With NUMLOCK UP,
press <Shift-End> to "jump" the "viewing window" to the
lower-left section of the image - the one you want to edit.
Press "Esc" and the image is now stored in memory as your
new 320x200x256 screen (but with a 1:1 aspect ratio). Click
EXIT and you are back at VGACAD's Main Menu with the section
to be edited.
6) Back at VGACAD, you'll notice that all the menus are
slightly "squished" but the screen looks like you "zoomed"
the 800x600x256 GIF. So far so good. All VGACAD functions
will work as normal (with the exception of resizing/flipp