Three-dimensional structure calculation: achieving accuracy without calibration

This paper addresses the problem of computing the camera motion and the three-dimensional structure of a scene using two uncalibrated images as inputs. The camera motion is calculated by estimating the essential matrix and using approximate values, easily available, for the intrinsic parameters. The classical eight-point algorithm to calculate the essential matrix is known to be very sensitive to pixel-noise even when the intrinsic parameters are perfectly known. This paper shows that by using the normalized eight-point algorithm, aimed at calculating the fundamental matrix, the pixel-noise sensitivity is reduced significantly. More importantly, we show that the intrinsic parameters do not have to be accurately known in order to get very good quality reconstruction. In particular, we have investigated and compared the effect of errors on the intrinsic parameters together with pixel-noise on the calculated motion/structure, when using the straightforward eight-point algorithm and its normalized version respectively. keywords: three-dimensional reconstruction, camera motion, essential matrix.