Indirect Epipolar Resampling of Scenes Using Parallel Projection Modeling of Linear Array Scanners

Linear array scanners are used as a substitute of two-dimensional/frame digital cameras since they can produce high-resolution digital images comparable to scanned aerial photographs. On the other hand, digital frame cameras have inadequate size that is dictated by technical considerations/limitations. In general, rigorous sensor modelling involves the description of the physical process of data capture using such a sensor. For imaging systems, rigorous modelling incorporates the system’s interior and exterior orientation parameters. Such parameters might not be always available for linear array scanners (e.g., commercially available IKONOS scenes). Deriving these parameters requires numerous ground control points. Moreover, the estimation process is geometrically ill posed due to the narrow angular field of view of the imaging system. Recently, parallel projection has emerged as an approximate model (for high altitude scanners with narrow angular field of view) that can be used to represent the mathematical relationship between scene and object space coordinates using few parameters. This paper outlines the derivation of resampling approach of linear array scanner scenes according to epipolar geometry. Conjugate points should have no y-parallax in the resampled scenes. Moreover, they should have an x-parallax that is linearly proportional to the corresponding object height. Such requirements can only be met by projecting the original scenes into a common horizontal plane. The paper explains the selection of such plane to meet these specifications. Experimental results using IKONOS data demonstrate the feasibility of the approach.