Linear Interpolation in image processing

Question

I am going through a paper in computer vision, and I came through this line :

the L values, or the luminance values, for these pixels are then linearly and horizontally interpolated between the pixels on the (one pixel wide) brightest column in region B, and the pixels in regions A and C.

What does linear and horizontal interpolation mean?

So I tried looking for linear interpolation, so does it mean that we average out the values of pixels which are linear to each other? As I can't see any proper definition.

Paper : http://140.118.9.222/publications/journal/haircut.pdf

Answer 1

Every programmer should know linear interpolation!!! Especially if you're entering the domain of image-processing.

Please read this and never ever forget about it.

https://en.wikipedia.org/wiki/Linear_interpolation

The paper describes pretty well what is going on. They synthesize skin texture by sampling the face and then interpolating between those samples. They sample 3 regions A, B and C.

They pick the brightest column of B, the left-most column of A and the right-most column of C.

Then for every row they linearly interpolate between the columns' pixels.