In an image both high resolution and low resolution pixel are present?

To enhance the resolution how the process goes on?

Answer 1

[Walter Roberson]

Image files do not often have a mix of pixel resolutions, but it is possible for some file formats; in particular it is possible for the TIFF file format. Do you have such an image file? If so then what format is it in?

I think you need to expand your question. Are you working on HDR (High Dynamic Range)? Are you working on Compressive Sensing?