I understand how write code to apply a convolution matrix to a pixel. Not that hard. Now each upscaling algorithm can be implemented using a convolution kernel. I am just not sure how to apply this to code. Lets say I have a 1000x1000 px image. And I upscale it to 1500x1500 px. Now each pixel maps to 1.5 pixels. How exactly do you apply your convolution in code ?
Could someone kindly show a sample code or pseudocode algorithm for this?