Detection of a known Object (By Template)

I need help with Object detection. I habe to detect position of a Fork and a Knife on a Plate. The Plate is on a Tray. The Objects are always the same but the Positions can vary.

I'm wokring with c开发者_运维技巧# and AForge + EmguCV

Can someone help me with this?

Here is a sample pic:

The brightness and color or the knife/fork-pixels are mostly determined by reflection, so I don't think classic template matching would work with this picture.

The knife has almost no corners, so I'm not sure if an interest point-based algorithm like SIFT would work here.

I think the best approach here could be to use an edge detector (Laplace, Sobel, Canny), trace the lines and perform geometric template-matching the way they did it back in the 1980's.

Here's a very good reference for this approach: Object Recognition by Computer

I would go for template matching methods which are looking image gradients. Those approaches are robust to changing lighting conditions.

You can take a look at the fast template matching algorithm implemented in: https://github.com/dajuric/accord-net-extensions

Samples included.

The implemented template matching algorithm is based on orientation of gradients, which are very resilient to changing lighting condition. In order to detect your object, a template must be made (e.g. in Paint) and then rescaled.