Both the working distance and the mechanical length of Core Plus lenses and illuminators have been optimised to make the system as compact as possible: compared to other telecentric lens
and illuminator systems with similar fields of view, the Core Plus series is up to 45 per cent shorter.
Also, the model described in this section is mainly based on the assumptions of the telecentric lens
, which cannot be applied directly to the standard perspective lens condition.
Such a 3D scanner working in micrometer range is typically equipped with a telecentric lens
having a limited Depth Of Field (DOF) at a specified working distance [WD.sub.C].
Zhang, "Design of an optical system consisting of a special telecentric lens
for side-scattering measurement on individual cells," Optical Engineering, vol.
Reference  theoretically describes the measurement errors caused by out-of-plane displacement and self-heating of the camera; it further establishes a high-accuracy two-dimensional digital image correlation (2D-DIC) system using a bilateral telecentric lens
to minimize the errors.
In the optical fringe projection system, a specially installed telecentric lens
, together with four-step phase shift method, was employed for the projection in order to retrieve accurate and real-time phase data of the deformed surface.
As usual for such sensors, it has a telecentric lens
. With such a lens, object rays are not running concentric, but approximately perpendicular to the very large lens plane and to the--relatively smaller--measuring object.
In fact, for real camera lenses, such as a fixed length lens, a zoom lens, or even an expensive high-quality telecentric lens
, image distortions unavoidably exist due to lens aberrations and misalignment of optical elements .
The TM includes a telecentric lens
for point-to-point measurements and image capture for local or network data storage.
VT-S700 uses a telecentric lens
and is said to reduce image distortion and improve inspection accuracy at the edges of large field-of-view.
For example, at the end of the white paper Will a Telecentric Lens
Optimize My Machine Vision System?