Averaging an image

A basic Image Processing question . How can I average the values or RGB for an input color image? If the input is a color image, the output I need is just the average value of RGB in the entire image. How can I do it?

Answer 1

[Walter Roberson]

One possible interpretation:

mean(YourImage(:))

Another possible interpretation:

mean(reshape(YourImage, size(YourImage,1) * size(YourImage,2), size(YourImage,3)))

Which you choose depends on whether you need the average R separate from the average G and average B (second expression) or if you are looking for the single over-all average value (first expression.)

[Niranjan]

I want only a single value of RGB as an output for the entire image. I can't understand your second expression but that gave me this.

[ 120.2294 115.3884 118.1661 ]

Is this what I am looking for? Please clarify me.

I am doing this operation in order to average an image ,to calculate the average value of RBG in the entire image.

[Walter Roberson]

Do you want the average R, the average G, and the average B? If so, that's what the second expression gives.

If you want a single value that averages the intensity of _everything_, then that is what the first expression gives.

If you want a simpler version of the second expression, it would be

mean(reshape(YourImage,[],size(YourImage,3)))

[Jan]

Or even simpler for RGB images: mean(reshape(YourImage, [], 3))