A new light source for camera and image sensor calibration from Gamma Scientific delivers higher spectral resolution and accuracy, together with a broader color gamut, compared to any previously available halogen or LED-based source. The new SpectralLED tunable light source accomplishes this by combining the output of 30 discrete LEDs, each having a different center wavelength. This enables the SpectralLED to be programed on-demand to produce output that closely matches virtually any illuminant source (e.g. blackbody, daylight, fluorescent, LED, CIE illuminants), or the spectrum of any illuminant reflected by a target (such as a Macbeth™ or X‑RITE™ target). The SpectralLED can even be swept through wavelengths to simulate a scanning monochromator, but with no moving parts.
In addition to superior spectral resolution and accuracy, the SpectralLED also offers about ten times higher brightness than any competitive product. This allows measurements over a much larger, linear dynamic range, and is sufficient to illuminate virtually any detector at levels up to saturation. And, no matter at what level the SpectralLED is driven, a combination of DC constant current drivers, optical feedback, and thermoelectric cooling maintains its high luminance accuracy in real time. This also allows source brightness to be varied directly (through drive current), rather than by pulsewidth modulation (PWM), thus eliminating any flicker.
Despite its technical sophistication, the SpectralLED is easy to use because the firmware allows all functionality to be simply accessed through ASCII commands sent over USB or RS-232 interfaces. All source calibration data, RMS fitting, and spectral presets are managed by the device internally, making it particularly well suited for embedded applications in production QA/QC.
The SpectralLED is intended to allow sensor, camera and system manufacturers to perform a wide variety of calibration and testing functions with a single instrument. Applications encompass smartphones/tablets, DSLR cameras, cinematography camcorders, diagnostic medical imaging, technical and industrial photography, or any OEM camera/sensor/detector application. Specific tasks include testing for white balance, spatial uniformity, defects, linearity, dynamic range, signal-to-noise, responsivity and ISO speed.
