Questions tagged [image-processing]

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44
votes
4answers
54k views

How is Gaussian Blur Implemented?

I've read that blur is done in real time graphics by doing it on one axis and then the other. I've done a bit of convolution in 1D in the past but I am not super comfortable with it, nor know what to ...
7
votes
3answers
292 views

How to denoise video?

Video noise is random and not correlated in time. I assume, the best method is using wavelet denoise in this case, right? If yes, how is wavelet denoise implemented for video? Is there something to ...
5
votes
1answer
229 views

Why does an affine transform work only on three of the corners?

I am trying to use a linear transformation to straighten out the camera angle on this image: In other words, I want to transform the image into a head-on view of the whiteboard. I applied an affine ...
9
votes
3answers
1k views

What's a proper way to clamp dither noise?

When reducing color depth and dithering with a 2 bit noise (with n=]0.5,1.5[ and output=floor(input*(2^bits-1) + n)), the ends of the value range (inputs 0.0 and 1.0) are noisy. It would be desirable ...
6
votes
1answer
177 views

What is the state-of-the-art on using computers to “clean-up” images?

TWO PART QUESTION - We've all seen the movies/TV shows where the police/feds/spies use computer software to take a grainy photo and do a "clean-up" to see a better picture and more details. I assume ...
1
vote
1answer
31 views

How to create static alpha masks of an image

I have an image of following type- I want to create mask of the following type where the inside area is white and rest of it is black. How to do it?
0
votes
2answers
98 views

How RGB images are formed

I have a noob level question about RGB images- Pixels in RGB images are in the range of (0-255), so technically each channel ranges from 0(black) to 1(white), then why we say that each image has a Red,...