Sensor Performance Lab

The GeoEye Sensor Performance Lab provides full imaging system–calibration services
for remote-sensing payloads. System tools are built for multi-sensor analysis, and
services include:

  • Geo-location accuracy
  • Image-quality monitoring programs
  • Full turnkey systems for geometric and radiometric calibration and image-quality characterization

The Sensor Performance Lab will also monitor GeoEye-1, the world’s highest-resolution commercial satellite, launching in 2008.

Capabilities

Geometric Calibration: Provides ground-processing systems with the necessary parameters to accurately geoposition image pixels. Calibration parameters are determined by acquiring and analyzing imagery over GeoEye Geometric Calibration ranges. The calibration ranges provide a dense set of high-accuracy control points, while the calibration system supplies automated image measurement in the imagery control points. Triangulation and regression are then used to determine the optimal calibration parameters. Parameters include:

  • Telescope focal length
  • Perspective center
  • Field angle map
  • Star track alignments
  • Gyro alignment
  • Gyro calibration

Geo-location Accuracy Assessment: Verification of the accuracy of a geo-location imaging system is performed by comparing image measurements against high-accuracy control points. In addition to the geometric calibration ranges, worldwide Test and Evaluation (T&E) sites are used to measure the imaging system’s CE90/LE90 accuracy. The T&E sites allow for frequent accuracy assessments around the world, separate from the calibration sites.


Radiometric Calibration: Equalizes the individual detector response to produce uniformity and eliminate visual artifacts, such as streaking and banding, intrinsic to digital scanning–imaging systems. Absolute radiometric calibration sets the in-band at-aperture radiance for the multi-spectral and panchromatic channels. Depending on the sensor and platform capabilities, a variety of techniques can be employed to perform the relative and absolute calibration-parameter determination.

Image-Quality Assessment: Tools for measuring and analyzing key image-quality metrics, such as Modulation Transfer Function (MTF) and Signal-to-Noise Ratio (SNR), are available for on-orbit system characterization. These tools enable quality analysis on images of the Big Spring, Texas, test range. Hosted on platforms with high-quality calibrated displays and tuned image enhancement, they extract the most-complete information possible, ensuring the highest-quality results.