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Calibration Services

Calibration services for EO/IR imaging sensors and spectrometers.




Ground Truth


Lab Calibration

Laboratory spectral and radiometric calibrations are performed by OptoKnowledge on all EO/IR sensors covering the spectrum from the visible to the long wave infrared.

Radiometric calibration sources typically used include NIST traceable irradiance lamps and blackbodies

Infrared calibration is often performed with nitrogen purge to remove the absorption by CO2 and H2O in the air. This provides a true response of a sensor over its entire range.

Spectral calibration is performed using a variety of lasers and gas discharge lamps (e.g., He, Ar, Kr, Hg, etc.). Spectral calibration in the infrared is performed using band pass filters.

As necessary, the calibration set up uses integrating spheres and collimators to assure repeatability. Multiple sources are often used simultaneously and injected directly into a collimator or an integrating sphere.

Each specific sensor is calibrated based on the best technique for that sensor. OptoKnowledge designs and implements the calibration.

It is recommended that users of sensors that require quantitative analyses do not rely on a single calibration. Repeated calibrations at the user facility can be designed, assembled and delivered to the user. Sensor performance changes in time due to many reasons, including aging, shift of components (due to shipping and handling), etc.

Lab Calibration   Lab Calibration   Lab Calibration
Lab Calibration   Lab Calibration   Lab Calibration
Lab Calibration   Lab Calibration   Lab Calibration

Resolution / Color Calibration

Color standards can be very useful in the radiometric and spectral calibration of various imaging systems, spectrometers, and hyperspectral sensors that operate in the visible portion of the spectrum. Diffuse reflectance standards such as those shown in the picture below have a known spectrum and therefore can be used to validate a sensor's spectral response.

Custom software used with various color charts (see Gretag MacBeth chart below) are available for calibration and testing the performance of a sensor system. Each square in the MacBeth chart has xy values associated with the CIE color system. These serve as reference coordinates for the evaluation of the sensor performance in color reproduction.

We also use industry recognized standards (see ISO 12233 chart below) for resolution measurement and characteristics.

Contact OptoKnowledge for information about color (spectral) calibration of your sensors.

Gretag MacBeth Chart   ISO 12233 Chart   Diffused Reflectance Standards

Gretag MacBeth Chart


ISO 12233 Chart


Diffused Reflectance Standards


Dynamic Tests

Instruments are often designed for measuring time-dependent or very short-lived events. It is necessary to simulate such events in a lab environment where the event can be repeated as necessary to test triggering techniques and validate the spectral and radiometric calibration that are performed under static conditions.

Dynamic tests are also used to assess temporal response and synchronization. OptoKnowledge designs such time-dependent or short-lived events that are appropriate for the specific sensor and spectral range.

Examples below show electrical discharge that produces plasma and thermal radiation of dissociated and ionized air species. Such measurements are appropriate for high resolution spectrometers and radiometers.

A second example shows a Ammonium Perchlorate (AP) rocket engine fired in a static stand. The propellants used in this model rocket are similar to those used in solid propellant rocket and produce similar spectral signature.

Dynamic Tests   Dynamic Tests    

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