How can i take picture to call a number I think there was option in some app, dont remember what it was. But you could take picture to call it. 

I want to simply take picture of a number and call the number. Photo need not to be saved.

It'd be huge benefit to me. 

I think it should be possible i'm not talking about hand written numbers, i'm talking about numbers on screen or billboard etc.
Google Goggles will do what you are asking. It does an analysis of any taken picture (without saving it to your phone). The results of the analysis will depend upon your picture (for example, if you take a picture of a famous painting it will tell you what the painting is). 

In your case if you take a picture of a phone number, it will highlight the number in the picture allowing you to select and dial it.