How can I Count no. of objects in a image?

I want to count no. of objects like men (in a group photograph), coins in a image etc.

for ex-- http://blogs.mathworks.com/images/steve/2012/counting_features_01.png

please help me..

Answer 1

[Walter Roberson]

http://www.mathworks.com/matlabcentral/answers/39545#comment_82169

Quoting, as that comment will not automatically expand:

Does the 2 year old identify Barney as human? How about Sesame Street's Bert? Barney has a human inside the costume, so should be identified as human, but Bert is always a puppet and so should not.

Okay, now how about R2D2? Some versions of R2D2 have humans inside and so should be identified as human, but some of them are electromechanical. Can a 2 year old tell the difference? Likewise for the new Daleks, the authorized commercial versions of which are electromechanical, and some of the background Daleks in crowd scenes were electromechanical, but the close-ups in the Dr. Who series are only of Daleks with humans inside.

You are going to have to have excellent artificial intelligence indeed to count the number of humans that are in the Dr. Who group shot of a Dalek scene.

[Sanuj Shukla]

It's too complex to detect a complex figures( like human) that's why i was trying to find some easy shapes like coins, trees using some AI technique.

[Walter Roberson]

http://www.mathworks.co.uk/matlabcentral/answers/65467-counting-just-coins-in-this-image#comment_133262