Draw a rectangule when an object is recognized

Question

Hello everybody I am doing a project to recognize an apple using emgucv c# visual studio 2010 and neural network. I have a question. When the predict function return me value of class, I want to draw a rectangle in part of image that was recognized like apple and I do not know how. Do you have any idea for that?

Answer 1

There is no way to do it. A neural network does not actually detect an object. If just classifies vectors describing images into classes. However, the object itself is never recognized. The only thing that is recognized is the similarity or dissimilarity between two images. To achieve what you want, you need to use an object recognition method. Take a look here:

http://www.intorobotics.com/how-to-detect-and-track-object-with-opencv/

Answer 2

I answer the question regarding the classification network in you other post. A simple addition to your question about the rectangle: If you want to actually recognize the apple, not just classify the image that contains an apple, you can use histogram backprojection

The main idea is this: You take the images of some apples and extract the histogram. In this way, you have a probability distribution of "apple colors" (the image should be cropped, even showing part of an apple). Then you search an unknown image for areas with similar colors. The method is one of the simplest, and works quite well for skin detection (I don't know how well it works for apples, but it most probably does).