Calling all nerds: how do you make a histogram?

DoctorIt

Alright fellow geeks, i'm doing some image analysis and I need to write some code to give me a histogram for my images. I've got a 512x512 matrix of brightness values (0-255).

so my question is, are the histograms we see in photoshop, or our camera's just a plot of number of pixels at a given value? As in, is the x-axis just 0-255 and the y-axis number of pixels? I'm thinking yes, but you never know.

chime in, let's nerd out! :freaky

JamesJWeg

I am thinking yes as well, but I don't know for sure.

James.

JamesJWeg

Did you see this?

http://www.ph.tn.tudelft.nl/Courses/FIP/noframes/fip-Statisti.html

James.

DoctorIt

JamesJWeg wrote:

Did you see this?

http://www.ph.tn.tudelft.nl/Courses/FIP/noframes/fip-Statisti.html

James.

Yowza! good one

ian408

GNUPlot?

Ian

Richard

DoctorIt wrote:

As in, is the x-axis just 0-255 and the y-axis number of pixels? I'm thinking yes, but you never know.

chime in, let's nerd out!

That sounds just about right, but the y-axis would need to be scaled as a function of the total number of pixels.

DoctorIt

rsinmadrid wrote:

That sounds just about right, but the y-axis would need to be scaled as a function of the total number of pixels.

Doesn't need to be, but you're right. I ended up writing my code that way anyway. Normalized it, looks nicer than having really huge numbers.

So turns out it was pretty easy. Just thought I'd engage any fellow nerds.

thanks for the links.