what is difference between structure image and texture image
There is a growing awareness that images are not homogeneous and that it could be useful to model them as a combinaison or superposition of morphological components that have distinct properties. One can cite four main components: piecewise-smooth parts, contours, geometrical/periodic textures and a last one, barely modelled, sometimes termed noise. 

The edge-cartoon/texture is a common name given to a more macroscopic version with two components: structure and texture. Structure often refers to the piecewise-smooth parts and large-scale contours, texture to geometrical and almost periodic textures, noise. Sometimes, they are called geometry and oscillatory components. Related works are mentioned in Structure-Texture Image Decomposition: See for instance: Image decomposition toolbox



When the contours of an object are not distinct, its textural aspect can help to segment it. The color aspect is often put on the "texture" side.