Once I had 10,000 NSFW images in a collection of 1,000,000. You might say that 99% of the images are good and for most classification problems 99% accuracy would be wonderful.
But it's not good enough.
You might find some simple tricks that eliminate 90% of those NSFW images and now you have 99.9% accuracy. That makes you look like a genius in the machine learning world.
But it's not good enough. Even 99.99% accuracy (100 bad images) is not good enough
Even if somebody found one NSFW image you could get kicked out of Adsense. One child porn image uploaded to your site won't put you in jail but it is still completely unacceptable.
Comments
The difficulty of it is the imbalance.
Once I had 10,000 NSFW images in a collection of 1,000,000. You might say that 99% of the images are good and for most classification problems 99% accuracy would be wonderful.
But it's not good enough.
You might find some simple tricks that eliminate 90% of those NSFW images and now you have 99.9% accuracy. That makes you look like a genius in the machine learning world.
But it's not good enough. Even 99.99% accuracy (100 bad images) is not good enough
Even if somebody found one NSFW image you could get kicked out of Adsense. One child porn image uploaded to your site won't put you in jail but it is still completely unacceptable.