Difference of Box (DOB)
The Difference of Box module is a filter that identifies edges. The DOB filter is similar to
the LOG and DOG filters in that it is a two stage edge
detection process.
The DOB performs edge detection by performing a mean blur on an image at a specified
window size. The resulting image is a blurred version of the
source image. The module then
performs another blur with a smaller window size that blurs the image less than previously. The final
image is then calculated by replacing each pixel with the difference between the two blurred
images and detecting when the values cross zero, i.e. negative becomes positive and vice versa.
The resulting zero crossings will be focused at edges or areas of pixels that have
some variation in their surrounding neighborhood.
Interface
Instructions
1. Specify the window size of the first blur to be performed. The window
size is how large a mean filter is applied to the image.
2. Specify the window size of the second blur to be performed. Note that the
window size should typically be larger then the first window size in order to correctly detect
edges.
Example
| Source | DOB |
 |  |
See Also
Difference of Gaussian
LOG
Mean Filter
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