Transformation method of three-dimensional object points onto two-dimensional image points for linear pushbroom images

Abstract

This invention provides a method to transform 3D object points onto 2D image points for linear pushbroom images. The problem is decomposed to the problem of finding sensor line coordinates and the problem of finding sensor column coordinates from linear pushbroom collinearity equations. The procedures to solve the problem are as follows. First, assume an initial value for image line coordinate to be sought for and using this value, calculate the sensor attitude. Next, assume the sensor attitude is constant and calculate a new image line coordinate satisfying linear pushbroom collinearity equations. Next, update the initial value with the image line coordinate calculated and continue the procedures until the difference between an initial value and a new value calculated becomes smaller than a threshold. If the different between an initial value and calculated value is smaller than a threshold, accept the calculated value as the sensor line coordinate. After finding the sensor line coordinate, calculate the sensor column coordinate satisfying linear pushbroom collinearity equations.