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Measuring FTM: Variant systems


The company OEG offers control benches for measuring the MTF (Modulation Transfer Function). The general solution proposed is the bench MTF Variant: This is a universal automated and can be adapted to any configuration object / image. Of course, these benches standards can be tailored to your application.
Strengths in systems VARIANT :
  • They can automatically characterize the image quality of an optical system on the axis or in the field whatever the azimuth and every configuration object / image possible
  • The automation of these systems allows for control of all of your optics. In this they fully meet all requirements that may have a workshop production
  • This modular system combines universal application, and easier to use. Measurements can be performed manually controlled using a joystick which makes systems VARIANT also perfectly suited for teaching and R & D
  • Ils ont été développés en étroite collaboration avec les fabricants d’optiques et sont devenus des systèmes incontournables pour les départements de fabrication d’optique et d’assurance qualité

Some examples of use systems VARIANT :

Object characterisation
Caractérisation de système afocal (télescope)
Caractérisation d'appareil photo


A bench of control necessary for the manufacture of your optical

Principle of operation

The MTF is calculated by performing the Fourier transform of the image of a slit (sagittal and tangential direction). The slit is imaged on a CCD camera by the sample under test and an objective microscope of the instrument (called objective "relay"). The tester includes a capture card and software for image processing that can scan and analyze the image of 32 bits and in real time. The software contains data of optical lenses used relays and control procedures for automated measurements using up to 6 axis motor.

The measurement data are displayed as a graph and an array. They can be easily exported. Many options are also available. For example, the operator can return the minimum values with respect to the contrast for each spatial frequency and the software sounds an alarm if these values are below the desired values. The sequence of steps can be programmed by the user easily.

VARIANT benches are very well suited to the characterization of a wide range of components and optical systems such as:

  • Lens
  • Doublet
  • Telescope
  • Camera
  • Microscope
  • Projection lens
  • Intraocular lens
  • Contact Lens
  • Guide light in fiber optic network
  • Light intensifier tube
The bench VARIANT in summary:
  • Real-time display of the FTM, the ESF (Edge Spread Function) or LSF (Line Spread Function) on the computer screen
  • Rapid switching configuration sagittal to tangential configuration (see immediately if you use a cross instead of a slot)
  • Displaying the FTM for fine tuning during assembly of the object
  • Rapid change in the wavelength of study
  • Rotation is manual or automatic sample with 360 ° display of contrast values for a given spatial frequency and free selection of the number of azimuths to use
  • Use and control of the bank by the joystick, mouse and keyboard of the computer
  • Graphical and numerical representation of values measured
  • Automatic production of certificate action
  • Displaying the curve Focus (contrast for a given spatial frequency)
  • Focus manual or performed by computer
  • A wide range of possibilities: from bench fully automated to bench fully manual
  • Measurement procedure easily programmable by the user


Bench FTM Variant

Measurement Accuracy of FTM

± 0,02
Repeatability of measurement FTM
± 0,02
Precision measurement of length
± 0,5%
Frequency Range
0...200 cycles/mm (*)
Height of the object
<100mm, adjusted automatically (*)
Image Height
<30mm, adjusted automatically (*)
Measuring azimuth (**)
360°, manually or automatically
Range of focal length (**)
2...200mm (*)
Type of measure (**)
Optical length
200...800mm (*)
Spectral Range (**)
Measure depending on the wavelength
Yes (with filters)
Numerical aperture of the target relay
Yes (at desired spatial frequency)
Automatic measurement procedure
Yes (up to 6 axes)
Maximum diameter of the sample (**)
100mm (*)
Measurement Principle
Processing the image of a slit (sag/tan)
Measurement procedure manual
Yes, thanks to the joystick
Exploitation system
Windows 2000/XP

32 bits

Pentium IV, 256MB RAM, 32MB VGA

Documentation en ligne :

Download the brochure on the banks of FTM VARIANT

Link to the website of the company OEG

If you would like more information, please contact us.

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