EdgeDetector is a program that detects edges from a gray scale
image in GIF format. Version 1.0 was made available in April 1999, while Version 1.1 was
made available in June 1999. All versions have been tested on Windows 98/NT and Solaris.
How to use EdgeDetector:
- Download EdgeDetector 1.0 or 1.1.
- Use the original head image, or one of the smoothed
images or another image that meets the requirements for the input image
specified at the bottom of this page.
- Type: ED InFileName OutFileName LL ES. Here:
- ED is "EdgeDetector", in case of EdgeDetector 1.0; or "EdgeDetector11"
in case of EdgeDetector 1.1.
- InFileName is the name, including the path, of the
input image file name. It must end with the
extension of ".gif".
- OutFileName is the name, including the path, of the
result image file name that contains the detected
edges. The output image will be GIF format. Thus
the file name should end with the extension of ".gif".
If not, such an extension will be added to the
specified file name.
- LL denotes the lower limit of the edge contrast.
It can be any number no smaller than zero and
greater than 100.0
- ES denotes the edge strength. It can be any number
no smaller than zero and greater than 100.0
- Please email me (wwzhou at yahoo dot com) your
comments/suggestions. If you would like to be notified about future releases of
EdgeDetector, please say so.
The effect of the last two parameters, LL and ES are demonstrated with
examples. Both of them are used in a relative
sense. In other words, edges with the same contrast and strength may
not be detected from two different images with the same values for LL and ES,
depending on the number of edge pixels present in the images. With the same
values for LL and ES, EdgeDetector 1.0 and EdgeDetector 1.1 usually detect
different numbers of edge pixels from the same image.
Generally speaking, the greater the values of LL and ES are set, the more pixels
will be highlighted in the output image as edges. If either LL or ES
is set to zero, no edge in the image will be considered strong enough
to be highlighted. If both LL and ES are set to 100, all pixels that
compose an edge, no matter how weak it is, will be highlighted in the
If LL is set to 100, EdgeDetector can be used to obtain the results
shown in the examples by appropriately
setting values for ES and smoothing the original images.
Requirements for the input image:
- The input image should be in GIF format.
- Either dimension of the input image should not be greater than
- The input image should be a gray scale image. If it contains
three bands, only the red band will be used. In other words,
edges visible only in the green and blue bands will not be detected.