| Raster
To Vector Conversion
A raster is an image made up of pixels, dots on a screen,
which has no intelligence within a CAD program.
A vector is an image created mathematically using location
points x,y to x,y draw a line, circle, arc, etc., used by
CAD programs.
Raster
to Vector conversion is an automatic software program which
only works with black and white images. The software picks
up a pixel or dot (which is part of the image) looks for a
second pixel touching it, if more then 5 pixels are touching
then the software starts the first x,y point and places the
second x,y point when the dots or pixels stop.
This
is a very simplified version of what happens but helps to
explain the limitations of such a process.
The
software can not pick dots or lines smaller then 5 pixels.
If a line starts to bend out of reach, then a second line
is started. Text is still a major problem for CAD drawings,
OCR works well with text documents produced on a computer.
but not with CAD.
Many
CAD drawings still have text produced by hand but even if
the drawing is CAD produced, the variations of text height,
spacing and type and style make it very difficult.
This
process is very horses for courses and should not be confused
with a true CAD drafted drawing, but it can produce some good
results, quickly and cost effectively.
The
final result is dependant on a number of factors being mainly
the quality of the original but most importantly the method
of scanning and the processes used to set up the software
before converting.
Once
the drawing has been converted, for the best result, produce
a print and then change the areas which require attention.
This
process is ideal for building outlines, contours and complex
shapes or can be used as an overlay or back cloth and redrawn.
Examples
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