Question

what is contextual meaning of 'image' and 'pressure'​

Answer 1

Contextual image classification, a topic of pattern recognition in computer vision, is an approach of classification based on contextual information in images. "Contextual" means this approach is focusing on the relationship of the nearby pixels, which is also called neighbourhood.

the force produced by pressing against something: [ U ] air/blood/water pressure. [ C/U ] physics. Pressure is also the force that is put on a surface with reference to the area of the surface.