January 2018
Intermediate to advanced
268 pages
6h 20m
English
Content preview from OpenCV 3.x with Python By Example - Second Edition
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What's happening underneath?
The vignette filter basically focuses the brightness on a particular part of the image and the other parts look faded. In order to achieve this, we need to filter out each channel in the image using a Gaussian kernel. OpenCV provides a function to do this, which is called getGaussianKernel. We need to build a 2D kernel whose size matches the size of the image. The second parameter of the function, getGaussianKernel, is interesting. It is the standard deviation of the Gaussian, and it controls the radius of the bright central region. You can play around with this parameter and see how it affects the output.
Once we build the 2D kernel, we need to build a mask by normalizing this kernel and scaling it up, as shown ...
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