A method for rectifying grid junctions in grid-coded images using cross ratio

In the grid-coding technique, the accurate grid junction locations are vital to the surface computation. Noise arising from the imaging formation and processing processes will jeopardize the computation accuracy. The objective of this study is to make use of the geometric property of cross ratio to improve the accuracy of grid junction locations in grid-coded images. A method is devised to regenerate grid junctions from the original (i.e., raw) junction data of an image. Through a statistical error analysis, we show that the regenerated junction data are generally more accurate than the old ones in the image taken from a wide range of viewing angles.