<p>i stumbled across something like this lately here, but no code or service for now. <a href="http://cs.stanford.edu/people/karpathy/deepimagesent/" rel="nofollow">http://cs.stanford.edu/people/karpathy/deepimagesent/</a>  or here <a href="http://arxiv.org/abs/1411.4555" rel="nofollow">http://arxiv.org/abs/1411.4555</a></p>
Detecting subject in images
<p>I know there are some pretty impressive detection engines out there, which will let you input an image, and out comes whatever is the "main subject" in the image.</p>

<p>Lets say you give it a picture of a football, and it will return the text "football".</p>

<p>However I dont recall what these engines are called, and I just wonder if anyone has any pointers or names for good detection engines I can use with PHP?</p>