LMK special imaging

FishEye / Hemispheric lens

The hemispheric lens (FishEye) enables the user to cover an object field at a field angle of ± 92°. Thus this lens can be used for capturing wide lighting scenarios. For example the measuring and determination of artifical indooe lighting and the afterwards assessment of the UGR analyzing the luminance distribution

Conoscopic lens

For measuring and analysis of an angular depending luminance distribution of very small objects, for example determining the angular spread of display contrasts, a conoscopic lens (hypercentric lens) is offered. Thus luminances for many viewing angles ± 60° (circular) can be recorded in one image.

konoskopisches Objektiv konoskopisches Objektiv LMK 5 + konoskopisches Objektiv LMK 5 Color + konoskopisches Objektiv

For the evaluation of luminance images captured with the conoscopic lens a LMK LabSoft AddOn is available.
With this the allocation of luminances and derived measuring values to angular coordinates of the lens or transformed spherical coordinates is easily possible.

The LMK Conoscopic Contrast Measurement is a software addon designed for using the LMK with a hypercentric lens (Conoscope).
Macroscopic lens

For small object fields or tasks that does need a high magnifying a set of Macroscopic lenses offering various small measuring fields at certain measuring distances are available.
Using a modular lens construction system,TechnoTeam is able to build customized Macroscopic lenses according to customers needs.

The quality of display glasses can be measured with the LMK AddOn "Pixel crosstalk" ("pixel override"). It is used to characterize the loss of image clarity caused by anti-glare coatings. Using LMK, the scattered light generated in the display can be evaluated in combination with a macro lens. The basis for the measurement and evaluation is the article "Pixel Crosstalk: A New Metric to Characterize DOI Loss Due to AG Treatments of Display Glasses” von Thomas Fink und Udo Krüger.
AR/VR front-stop lenses

Imaging LMK with special adapted lenses offers an effective and efficient alternative for the metrological characterization of near-eye display systems (NED).

The user of a NED system perceives the whole image field only if his eyes are within the so-called Eye-box of the NED system. For each eye, the Eye-box corresponds to a 3-dimensional space around the respective exit pupil (XP) of the optical system.
Often the diameter of the NED-XP is larger than in conventional optical instruments (e.g., microscopes) and the distance to the last optical surface (Eye-relief) is relatively small.

For a correct photometric or colorimetric perception-accurate measurement, the entrance pupil (EP) of the measuring system must be located in the XP of the NED system, analogous to the human eye. On the other hand, it must be ensured that the EP of the measuring system is smaller than the XP of the NED system in order to achieve a complete filling of the aperture of the measuring system. Thus, valid measurement data can be guaranteed.
If the LMK aims to capture the complete NED field of view, the LMK-EP has to be placed in the NED-XP within the Eye-box. For this purpose, an optical system is necessary whose aperture-stop (respectively the EP) is in front of the optical surfaces.

Beside the existing conoscopic lens that offers a virtual EP (appr. 2mm diameter) in front of the lens and a measuring field of 120° a special front-stop lens was built.
This front-stop lens works with a real intermediate image plane and can be equipped with several focal lengths of 8mm; 12mm and 16mm. Thus it offers a measuring field of 30°- 60°. The diameter of the EP can be changed from 2 - 7mm.

Contact

Publications