machine learning? because you also want to filter cats.
Machine learning is a field of research, not a magical incantation that you say to solve everything.
What is the best way to programatically detect porn images? (2009)
31–40 of 110 posts
Re: What is the best way to programatically detect porn images? (2009)
#32This is probably going to get downvoted, but if lots of people are not overzealous puritans and want some skin, the best overall system design that maximizes happiness and profit is probably sharding into puritanweirdos.example.com with no skin showing between toes and top of turtleneck (edited to add no pokies either) and normalpeople.example.com with 99% of the human race The best solution to a problem involving co…
Porn detection still has its uses and you're making the mistake of saying that only puritans are interested in porn detection.
For example if you've got children, given your stance on the matter, you may not necessarily agree that a filter is necessary, but how about being alerted when your children are viewing obscene content? How about being alerted when your children are engaging in sexting?
When it comes to children, maintaining their purity is only one side of the coin, a necessity with which not all people necessarily agree. But the other side of the coin that's a pretty objective fact is that children do get the wrong ideas about what they see and sometimes it happens with adults too, with porn being the main reason why men think they need big penises to satisfy women. And there's a lot of weird porn out there. With improper exposure, a child can end up growing with certain ideas about doing sex, with certain complexes and so on.
And I'm not necessarily for censoring that content, as children can find ways around the censorship should they want to, plus these filters aren't perfect anyway. But I would find useful a system that alerts me when my child gets exposed to porn, such that I can take appropriate measures, like having fatherly talks about sex, explaining to him that what he just saw is a really bad idea in case he looked at something weird.
Plus, exposure to porn can happen 100% by accident and that's my personal problem with it. I take my monthly dosage for appealing to my stockings fetish, but you know, I like to be in control of when that happens. Like going to a website and clicking on something can trigger a popup involving ads to either poker games or porn. Sometimes they've got sound too. Imagine hearing in the workplace the sound of a woman's moan. It's totally disrespectful to your colleagues, as it disrupts their workflow. I was searching for something on ThePirateBay once and it happened to me.
Re: What is the best way to programatically detect porn images? (2009)
#33This is a classic categorical problem for machine learning. I'm surprised so many suggestions have involved formulating some sort of clever algorithm like skin detection, colors, etc. You could certainly use one of those for a baseline, but I'd bet machine learning would out-score most human-derived algorithms.
Take a look at the scores for classifying dogs vs cats with 97% accuracy http://www.kaggle.com/c/dogs-vs-cats/leaderboard. You could use a technique of digitizing the image pixels and feeding to a learning algorithm, similar to http://www.primaryobjects.com/CMS/Article154.aspx.
Re: What is the best way to programatically detect porn images? (2009)
#34I have developed an algorithm to detect such images, based on several articles published by research teams all over the world (it's incredible to see how many teams have tried to solve this problem!).
I found out that no single technique works great. If you want an efficient algorithm, you probably have to blend different ideas and compute a "nudity score" for each image. That's at least what I do.
I'd be happy to discuss how it works. Here are a few techniques used:
- color recognition (as discussed in other comments)
- haar-wavelets to detect specific shapes (that's what Facebook and others use to detect faces for example)
- texture recognition (skin and wood may have the same colors but not the same texture)
- shape/contour recognition (machine learning of course)
- matching with a growing database of NSFW images
The algorithm is open for test here: http://sightengine.com It works OK right now but once version 2 is out it should really be great.
Re: What is the best way to programatically detect porn images? (2009)
#35Whilst I agree that programmatically eliminating porn images is a very hard problem. Programmatically filtering porn websites might be easier, beyond just a simple key word search and whitelist. If you assume that porn tends to cluster, rather than exist in isolation, then a crawl of other images on the source pages , applying computer vision techniques, should allow you to block pages that score above a threshold nu…
"score above a threshold number of positive results" How about social scoring? A normal (or even a weirdo) teenage boy would spend less than a second examining my ugly old profile pix, but after ten or so of your known teen male users are detected to spend 5 minutes at a time, a couple times a day, closely studying a suspected profile pix, I think you can safely conclude that pix is not a pix of me and then flag / ce…
The graph theorist in me is rubbing my hands in glee at the thought of seeing if you could extrapolate out that approach to catch a broader range of offensive imagery through relationships and usage patterns.
Re: What is the best way to programatically detect porn images? (2009)
#36Wouldn't testing for skin colors produce far too many false positives to be useful? All these beach photos, fashion lingerie photos, even close portraits. And how about half of music stars these days who seem to try to never get caught more clothed than half naked? Nudity != porn and certainly half-nudity != porn. I'd rather go for pattern recognition. There's lot of image recognition software these days that can dis…
"detect certain body parts" When I was a kid, we had a firewall at school that tried to filter pornography by doing something similar with text. Doing research on breast cancer turned out to be rather tricky. So let's say you try to detect certain body parts. Now you have someone who wants to know more about their body, but you are classifying images from medical / health articles as pornography. "certain body config…
You are correct and I'm not saying that I described the Holy Grail of detecting porn in a single paragraph. I'm just pointing to another direction. No solution to a very complex problem could be one-dimensional. Combining several different tests might lead to a solution. I.e. these jujitsu photos should not even be detected as “certain body configurations” as people there are fully clothed and there's not much actual bodies seen in the picture (so mentioned skin color definitely should come to play when detecting wether you see a body or not).
At the end of the day I doubt there could be a fully bulletproof and always correct solution using current state of tech. But you need to factor much more than just skin color if you try to build an automated solution to this problem.
Re: What is the best way to programatically detect porn images? (2009)
#37Earlier quoted context omitted.
So i can literally get paid for looking at porn. Huh, who knew... :)
At the cost of your mental health, sure. I recall reading an article about the human workers who had this job at Google... they had crap benefits, crap pay, and no mental healthcare. As a result a lot of the people in the field had depression and other mental issues.
And RSI as well I would imagine.
Re: What is the best way to programatically detect porn images? (2009)
#38I used pifilter (now WeSEE:Filter , http://corp.wesee.com/products/filter/) for a production, realtime, anonymous confession site (imeveryone.com) in 2010.
It cost, IIRC, a tenth of a cent per image URL. Rather than being based on skin tone, it was created based on algos to specifically identify labia, anuses, penises, etc. REST API: send a URL, get back a yes/no/maybe. You decided what to do with the maybes.
My experience:
- Before launch, I tested it with 4chan b as a feed, and was able to produce a mostly clean version of b with the exception of cartoon imagery.
- It could catch most of the stuff people tried to post to the site. Small breasted women (being that breasts are considered 'adult' in the US) was the only thing that would get through and wasn't a huge concern. Completely unmaintained public hair (as revealing as a black bikini) would also get through.
- Since people didn't know what I was testing with they didn't work around it (so nobody tried posting drawings or cartoons), but I imagine eg a photo of a prolapse might not trigger the anus detection as the shape would be too different.
- pifilter erred on the side of false negative, but one notable false positive: a pastrami sandwich.
Re: What is the best way to programatically detect porn images? (2009)
#39This is probably going to get downvoted, but if lots of people are not overzealous puritans and want some skin, the best overall system design that maximizes happiness and profit is probably sharding into puritanweirdos.example.com with no skin showing between toes and top of turtleneck (edited to add no pokies either) and normalpeople.example.com with 99% of the human race The best solution to a problem involving co…
Porn detection still has its uses and you're making the mistake of saying that only puritans are interested in porn detection. For example if you've got children, given your stance on the matter, you may not necessarily agree that a filter is necessary, but how about being alerted when your children are viewing obscene content? How about being alerted when your children are engaging in sexting? When it comes to child…
children do get the wrong ideas about what they see and sometimes it happens with adults too, with porn being the main reason why men think they need big penises to satisfy women
Is it porn that gives them the wrong idea, or is it because porn is the only concept of sex that they get exposed to?
But I would find useful a system that alerts me when my child gets exposed to porn, such that I can take appropriate measures, like having fatherly talks about sex, explaining to him that what he just saw is a really bad idea in case he looked at something weird.
Why wouldn't you have fatherly talks about sex regardless of exposure to porn?
Imagine hearing in the workplace the sound of a woman's moan. It's totally disrespectful to your colleagues, as it disrupts their workflow.
Playing any sound is disrespectful to your colleagues, by breaking their concentration. The pornographic part is irrelevant.
Re: What is the best way to programatically detect porn images? (2009)
#40Earlier quoted context omitted.
"detect certain body parts" When I was a kid, we had a firewall at school that tried to filter pornography by doing something similar with text. Doing research on breast cancer turned out to be rather tricky. So let's say you try to detect certain body parts. Now you have someone who wants to know more about their body, but you are classifying images from medical / health articles as pornography. "certain body config…
You are correct and I'm not saying that I described the Holy Grail of detecting porn in a single paragraph. I'm just pointing to another direction. No solution to a very complex problem could be one-dimensional. Combining several different tests might lead to a solution. I.e. these jujitsu photos should not even be detected as “certain body configurations” as people there are fully clothed and there's not much actual…
There's plenty of fully clothed porn out there. They're even tags on some porn sites.