A Camera Model for Line-Scan Cameras with Telecentric Lenses

Abstract

We propose a camera model for line-scan cameras with telecentric lenses. The camera model assumes a linear relative motion with constant velocity between the camera and the object. It allows to model lens distortions, while supporting arbitrary positions of the line sensor with respect to the optical axis. We comprehensively examine the degeneracies of the camera model and propose methods to handle them. Furthermore, we examine the relation of the proposed camera model to affine cameras. In addition, we propose an algorithm to calibrate telecentric line-scan cameras using a planar calibration object. We perform an extensive evaluation of the proposed camera model that establishes the validity and accuracy of the proposed model. We also show that even for lenses with very small lens distortions, the distortions are statistically highly significant. Therefore, they cannot be omitted in real-world applications.

A Multi-view Camera Model for Line-Scan Cameras with Telecentric Lenses

“…Our model of the interior orientation of telecentric line-scan cameras is derived in [42,Section 4.1]. In this section, we will give a concise description of the model.…”

“…The telecentric line-scan camera model that we have described has a few important degeneracies, which have been investigated in detail for the single-view case in [42,Section 4.4]. Almost all of them also apply to the multi-view case.…”

“…The value of s x is known from the specification of the sensor. Furthermore, s y is only used to specify the principal point in pixels and is therefore kept fixed at the initial value specified by the user [42,Remark 19]. The next remark discusses the reasons for our choice of this overparameterization.…”

“…A camera model for setups with a single line-scan camera with a telecentric lens has been recently proposed in [42]. In contrast to entocentric lenses, which perform a perspective projection, telecentric lenses perform a parallel projection of the world into the image.…”

“…In this paper, we extend the single-view telecentric linescan camera model proposed in [42] to the multi-view case with an arbitrary number of cameras. Since there currently are no multi-view camera models for telecentric line-scan cameras that we are aware of, we discuss the most closely related work on two-view camera models for entocentric line-scan cameras in Sect.…”