Ask HN: Image Recognition APIs / Libraries for iOS

Me and my friend are starting to work on an idea as a way to get into mobile development. We wanted to incorporate an image search like Meal Snap or Snooth Wine Pro for some specific products.

I was wondering if someone could point me in the right direction w.r.t. papers, libraries or APIs that could be used for image recognition (iOS as well as Android platform).

I looked at Tineye but I find their costs to be prohibitive for a side project.

Thanks