The objective of photogrammetry is to extract information from imagery.With the increasing interaction of sensing and computing technologies,the fundamentals of photogrammetry have undergone an evolutionary change in the past several decades.Numerous theoretical progresses and practical applications have been reported from traditionally different but related multiple disciplines,including computer vision,photogrammetry,computer graphics,pattern recognition,remote sensing and machine learning.This has gradually extended the boundary of traditional photogrammetry in both theory and practice.This paper introduces a new,holistic theoretical framework to describe various photogrammetric tasks and solutions.Under this framework,photogrammetry is generally regarded as a reversed imaging process formulated as a unified optimization problem.Depending on the variables to be determined through optimization,photogrammetric tasks are mostly divided into image space tasks,image-object space tasks and object space tasks,each being a special case of the general formulation.This paper presents representative solution approaches for each task.With this effort,we intend to advocate an imminent and necessary paradigm change in both research and learning of photogrammetry.