Method for Absolute Calibration and Tracking of Large Format Detectors Using Laser Radar

instrumentation
Method for Absolute Calibration and Tracking of Large Format Detectors Using Laser Radar (GSC-TOPS-87)
Usage of laser radar to locate and determine orientation of large format detector to an impressive degree of precision to aid with the optical alignment of various systems and instruments.
Overview
A method developed to directly measure and map the physical location and orientation of large format detector active pixel arrays in a given coordinate system. This method tackles some of the challenges currently in existence.

The Technology
The purpose of this technology is to obtain charge coupled device (CCD) pixel location knowledge in 6 degrees of freedom with detector alignment precision of tens of microns of absolute uncertainty in a mechanical coordinate system. This non-contact approach involves the use of laser radar to obtain the orientation of the CCD pixels on a large format detector. This information can be used to align a detector in an optical system or interpolate image data from the CCD and correlate image features with physical locations in real space. The X, Y pixel value results for image analysis can be transformed into a three dimensional coordinate system. Using the laser radar, the CCD pixels are physically mapped and then related to external metrology targets on the detector housing. To accomplish this mapping, the laser radar is pointed at and focused on three or more locations on the detectors active area where a full frame readout of the detector is captured. This approach addresses a couple of technical challenges. The first challenge was to place a detector accurately and effectively as to have the OTE pupil image in plane with the detector pixels. Lastly, once the detector alignment is accomplished, how can the location of key features be established in the working coordinate system. This solution satisfies both of those challenges.
International Observe the Moon Night
Credit: NASA/GSFC/Debbie Mccallum
Benefits
  • Faster than measuring using a CMM
  • Easily extendable to CMOS arrays and IR-sensitive detectors
  • Precision level of tens of microns of absolute uncertainty

Applications
  • Medical device
  • Imaging and tracking
  • Meteorology
Technology Details

instrumentation
GSC-TOPS-87
GSC-17365-1
10191163
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