The dictionary says:
To introduce something extraneous between other things.
To alter by the insertion of new matter.
Suppose you have a photo that is 800x600 pixels.
You decide to make it bigger (1024x76.
Computer software will let you do that.
Just where did the software get those extra pixels?
The software will apply an algorithm (usually Bicubic) that generates extra pixels based upon adjacent pixels.
A photo that was taken at 1024x768 will be more accurate than a photo that was taken at 800x600 and then interpolated to 1024x768.
If your camera documentation says interpolated to 4 megapixel, it is likely a 2 megapixel camera which is using Bicubic to produce the extra 2 megapixels.
e.g. 1600x1200 interpolated to 2272x1704.
i recently bought a camera. it stated in its specifications that it has 4 megapixel interpolated. may i ask what does that means?