CamTest – Quality control of Camera Modules

OEM measuring chamber
OEM measuring chamber

The CamTest systems allow comprehensive measurements and quality controls for lenses, sensors and mounted camera modules before and during the ongoing production process, as well as a final quality control after the alignment process. Through the use of different innovative object generators, a variety of optical, opto-mechanical, color and sensor parameters are available.

CamTest can be used as stand-alone device. The measuring technology is housed in an OEM measuring chamber, which can also be integrated individually or in a ProCam Inline system for high volume production.

CamTest can also be used specifically for measurements in the research and development phase. 

Key Features

  • Standardized design for measuring almost all camera-relevant measurement parameters
  • Thanks to the modules with different object generators, the measuring principle can be used directly in an OEM measuring chamber
  • Can be used as stand-alone measurement system or as a fully integrated test module in mass production
  • Freely adjustable target limits with data logging for traceability and statistical process evaluation

Measurement parameters at a glance

  CamTest MTF CamTest Focus CamTest Chart CamTest Spectral
MTF, LSF or SFR, ESF x x - -
Through Focus, Tilt, Shift, Boresight - x - -
Distortion, EFL - - x -
Defect Pixel, FPN - - - x
Rel. Illumination, OECF, Dynamic Range - - - x
Colour Rendering, Spectral Response - - - x

Applications

  • Final Test of Camera Modules

CamTest MTF - One shot MTF-Measurement

MTF Measurement with fixed collimators
MTF Measurement with fixed collimators

In order to test camera modules with larger object distances, a structure with fixed collimators, which are preset for infinite or finite object distances, is suitable. In this case, the field of view depends on the actual object distance.

 

With this set-up, the MTF can be quickly and easily determined, furthermore, also Line Spread Function, SFR and ESF. This method is escpecially suitable for one shot MTF measurement for final quality check in high volume camera production.

CamTest Focus - For determination of Through Focus

latest generation of focussing collimators
latest generation of focussing collimators

The collimator projects the target virtual onto the test object. Through the use of focusable collimators, arbitrary object distances of 1m to infinity can be generated. This makes it possible to check the focus of fixed and autofocus modules. This set-up provides a field of view of+/-85°.

CamTest Focus measures parameters to determine the quality of the image, such as MTF, SFR, through-Focus MTF, tilt, shift and boresight.

Principle CamTest Focus
Principle CamTest Focus

Principle of CamTest Focus

The design with focusing collimators allows a variable object distance from finite to infinite in a measurement setup. Typical collimator arrangement, all of which point into the entrance opening of the test sample below.
(1) The Focusable Collimator
(2) Arrangement of several collimators for measurement from different angles
(3) Illumination of the autocollimator
(4) Reticle
(5) Variable measuring distance from finite to infinite through the focussed collimator
(6) Sample (lens and sensor)

CamTest Chart - For easy measurement of distortion

View into a test chamber for measuring the distortion
View into a test chamber for measuring the distortion

In setup with Test chart at finite obejct distance the field of view depends on the finite distance. A test pattern with infinity markers is projected and the position of the markers measured in the camera image. With the aid of a suitable optical structure, cameras with a highly distorted optical system can also be calibrated in this way. In a modified version of this setup, there is an imaging lens between the test sample and the chart to produce a virtual image of the chart as from an infinite distance.

This measuring principle is particularly suitable for measuring distortion, but also for measuring the effective focal lenght (EFL).

CamTest Chart Principle with chart
CamTest Chart Principle with relay lens

CamTest Spectral

Measuring chamber with an integrating sphere
Measuring chamber with an integrating sphere

Construction with integrating sphere and finite object distance. The integrating sphere serves as a light source in order to obtain the diffuse light required for the measurement. The possible field of view depends on the finite distance and the object generator. Because of the non-reflective special diffusor filter on the sphere opening, a uniformity of more than 95% could be reached.

Particularly suitable for the measurement of parameters such as defect pixels, FPN, color rendering, OECF, relative illumination and dynamic range.

CamTest Spectral Principle

At this point, TRIOPTICS relies on the proven algorithm from Image Engineering. 

Image Engineering's core competence is the measurement, analysis and improvement of digital image quality. Based on many years of experience with our independent test lab, we develop and produce test equipment for all modern camera types and distribute it to international customers.

For further information visit www.image-engineering.de