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  • Hacker News
  • For those who don't know, the author is a very prolific dev:

    https://github.com/zserge?tab=repositories&q=&type=&language...

    by hu3
  • 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.
    by jsmailes
  • From a 70s kid to an 80s kid, well done!
    by nakamoto_damacy
  • I too applaud this terrible (amazing) pun.
    by dcminter
  • Ditto. I’ve upvoted this based solely on the amazing title. Best toyline ever.
    by Xenoamorphous
  • Referencing "By the power of Grayskull!"
    by kazinator
  • IIIII HHHAAAAAVE THE POWERRRRR
    by mkaic
  • As an aside, "For the honor of grayscale" would work no worse here.
    by macleginn
  • This is really solid intro to computer vision, bravo!
    by swiftcoder
  • 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.
    by rmonvfer
  • 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

    by grep_it
  • Image pyramids are a brilliant method. The technique is hiding in many of the FCNN image segmentation models ive read.

    A truly clever image processing method.

    by aDyslecticCrow
  • 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...

    by atum47
  • I vaguely remember XnView having this matrix based custom filters.
    by smusamashah
  • At some point I would like to add more features as you described in your article; feature detection, image stitching...

    Here's the source code if anyone's interested https://github.com/victorqribeiro/customFilter

    by atum47
  • Appreciate the old school non-AI approach.
    by teiferer
  • But have a look at the "Thresholding" section. It appears to me that AI would be much better at this operation.
    by amelius
  • Classical machine vision and pattern recognition is absolutely AI. Or at least it was AI before it became too mature to be called that. As they say, any AI problem that gets solved stops being AI and becomes just normal algorithmics.
    by Sharlin
  • 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.

    by Cthulhu_
  • 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.

    by ryukoposting
  • Also resolution & uniformity

    Color makes major compromises physically also, since it seems like the Red, Green and Blue channels are sampling from the same physical location but the actual sensor buckets are offset from each other.

    by gridspy
  • Ah, I think you work in the same industry as me, machine vision. I completely agree with you, most applications use grayscale images unless it’s color-based application.

    Which vision library are you using? I’m using Halcon by MVTec.

    by vincenthwt
  • 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

    by shoo
  • Thanks for the reference. Looks very from-the-ground-up and comprehensive.
    by yunnpp