GFM - Technology

GFM counts on phase measuring fringe projection with digital micro mirror displays (DLP).

Precision by technology :
The Video by GFM and Texas Instruments.

Phase measuring fringe projection directly gains height values for any single surface point, from the gray value slopes of just a few phase shifted fringe patterns. A vertical scanning run of the camera is not necessary The measurement not only delivers an extreme height resolution (10...50 times smaller than the fringe width), it is also very fast.

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Fringe patterns consisting of parallel stripes are projected onto the object surface, and their perspective deformation is recorded by a camera. The high number of points acquired simultaneously delivers even smallest details. Last but not least, optical methods are extremely economical as they have no mechanical wear or disposables.

Advantages:

• Area based measurement
• Mesuring times from <<1 sec.
• Pixel wise height acquisition
• Extreme height resolution
• Large vertical range with one measurement
• Very low operational costs

Digital Light Processing (DLP):

Extreme light intensity and digital precision of the illumination are unsurpassable advantages of digital micro mirror displays, exclusively utilized for fringe projection by GFM. The microscopic mirror suspensions (picture, marked in red) have virtually unlimited life expectancy due to the effect of hyper elasticity. This together with high temperature stability and extremely low drift provides for continuously accurate measurements.

Figure: Micro mirror display, working principle (2 mirrors of 2 million), REM picture.

A Video from Texas Instruments featuring DLP-Technologie you'll find here:

Generating precise fringe phases by display technology

Gray value precision is decisive here, and with DLP this is granted by digital pulse width modulation. Due to their very fast switching times, DLP-Displays have a linearity much better than 1:1000!