Q:

Image analysis - how can I extract image label out of bottle

I am thinking of using OpenCV library for image analysis. Basically I want to automate in my project the extraction of image label from wine bottle.
This is the sample input image: 

This is the sample output:

I am thinking what should be my general strategy to extract the image. I am not asking for direct code. Just want to know the general approach to solve the problem.
Thanks!

A:

Sorry for vage answer but in applied computer vision is no such thing like general approach.

some will disagree of course but in reality
all CV applications are custom made for some specific purpose/task
in your case is the idea to find cylindric and probably standing object (bottle)
and then finding of irregular parts in it

I would do it like this:
1.remove noise as much as possible (smooth/sharpen filters)
2.(optionaly) reduce image data (via (i)FT or (i)DCT for example)
3.segmentate objects (usually by homogenity of color or by edge detection or by booth)
4.identify bottle object (by color,shape,or illumination (glass is transparent))
5.identify objects inside bottle (homogenity,not transparent,usually sharp edges,color is not good some labels are black on dark glass)
6.(optional) project label back from cylindric space to flat texture

[notes]

create app with many scrollbars and checkboxes
to be able to change all tresholds and enable disable filters or their order on the run
all parts will take a lot of tweaking of tresholds and weights
you have to do a lot of trial and error runs to find the best filters and their config for your task

