alt Hacker NewsBy the Power of Grayscale
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It may come as a surprise to some that a lot of industrial computer vision is done in grayscale. In a lot of industrial CV tasks, the only things that matter are cost, speed, and dynamic range. Every approach we have to making color images compromises on one of those three characteristics.
I think this kind of thing might have real, practical use cases in industry if it's fast enough.
About 15, 20 years ago I was still in uni and we had a computer vision lab, the main guy there had been working on that subject for years and dealt with businesses where his stuff was used for quality control.
Without fail, step one of computer vision was to bring the image down to grayscale and / or filter for specific colours so you ended up with a 1 bit representation.
My "algorithm" for a robot that was to follow a line drawn on the floor boiled down to "filter out the colour green, then look at the bottom rows of the image and find the black pixels. If they're to the left, adjust to the left, if to the right adjust to the right". Roughly. I'm sure it could be done a lot more cleverly but I was pretty proud of it AND the whole tool suite was custom made, from editing environment to programming language. Expensive cameras and robot, too.
I was working on a image editor on the browser, https://victorribeiro.com/customFilter
Right now the neat future it have is the ability of running custom filters of varied window size of images, and use custom formulas to blend several images
I don't have a tutorial at hand on how to use it, but I have a YouTube video where I show some of its features
https://youtube.com/playlist?list=PL3pnEx5_eGm9rVr1_u1Hm_LK6...
Really enjoyed this article, thanks for sharing!
I had recently learned about using image pyramids[1] in conjunction with template matching algorithms like SAD to do simple and efficient object recognition, it was quite fun.
1: https://en.wikipedia.org/wiki/Pyramid_%28image_processing%29
I’m not a “C” person but I’ve really enjoyed reading this, it’s quite approachable and well written. Thank you for writing it.
This is really solid intro to computer vision, bravo!
The blob-finding algorithm makes me think of the "advent of code" problems - I wouldn't have thought to do a two-pass approach, but now that I see it set out in front of me it's obviously a great idea. Seems like this technique could quite easily be generalised to work with a range of problems.
For those who don't know, the author is a very prolific dev:
https://github.com/zserge?tab=repositories&q=&type=&language...
This was a fantastic post. I've never really thought much about image processing, and this was a great introduction.
Didn't recognize George Smiley in those photos. Which makes sense, given he's an espiocrat.
Quality He-Man reference.
So, who is He-Man, and who is Skelator?
This title is excellent.
If you enjoyed this post you may also like the 2024 book foundations of computer vision: https://visionbook.mit.edu/
prior hn thread: https://news.ycombinator.com/item?id=44281506
i don't have any background in computer vision but enjoyed how the introductory chapter gets right into it illustrating how to build a limited but working simple vision system