The VLS-100 Variable Luminance Source is a controllable source of uniform, visible illumination for testing cameras, image intensifiers, and visible to near-infrared night vision devices. It is used with I-SITE™ software or as a standalone, computer-controlled device.
The Variable Luminance Source brightness is computer-controlled and continuously adjustable over a range of 2000cd/m2 -0.00001 cd/m2. Luminance accuracy is <3%*. The VIS-NIR spectral output remains constant over the entire brightness range. The source features a 50mm diameter output port with <5% luminance non-uniformity across the aperture.
*Stated luminance accuracy applies to output range of 2000-0.001 cd/m2. Values from 0.001-0.00001cd/m2 may exhibit a larger uncertainty.
Applications
Used in testing the performance of:
- Cameras
- Image intensifiers
- Night vision devices
Benefits
- Provides a controllable source of uniform illumination over a broad spectrum from the visible to the near-infrared
- Allows accurate luminance control over a wide dynamic range while maintaining constant spectral content (color temperature)
- Exceptional Luminance Range, Resolution, and Accuracy
Features
- Automated variable attenuator and aperture wheel with high resolution stepper motors
- Integrated photometer provides real-time monitoring of exit port luminance, allowing closed-loop control
- Filter drawer allows for multiple 50 x 50mm filters to adjust color temperature and spectral output
- Digitally controlled, laboratory grade power supply ensures constant lamp output and stable color temperature
- Dual integrating sphere design ensures exceptional illumination uniformity
- NIST traceable color temperature
- Custom targets available for objective or subjective metrology testing, boresight measurements, and contrast measurements
Measurements
The Variable Luminance Source,when accompanied by the appropriate measurement device and I-SITE™ software, can be used in the measurement of:
- Line Spread Function (LSF)
- Modulation Transfer Function (MTF)
- Phase Transfer Function (PTF)
- Signal Transfer Function (SiTF)
- Noise Power Spectrum (NPS)
- Root Mean Square Noise (RMS)
- Noise Equivalent Luminance (NEL)
- Noise Equivalent Radiance (NER)
The Variable Luminance Source is part of an overall measurement system and requires other measurement instruments to be effective.
This is an image intensifier using a visible source such as the VLS-100 Variable Luminance Source. The Photometric Camera uses a microscope objective for this application. The gain of an image intensifier is determined using the absolute luminance values measured on the phosphor surface.
| Performance | |
| Calibrated Luminance Range | 2000 cd/m2 – 0.001 cd/m2 |
| Min. Luminance (Uncalibrated) | 0.001 cd/m2 |
| Luminance Accuracy | <3% |
| Aperture Non-Uniformity | <5% |
| Spectral Range | VIS to NIR |
| Color Temperature | 2856 K ± 50 K |
| Rated Lamp Life | 2000 hours |
| Measurements (with I-SITE™ software and appropriate measurement device) | |
| Line Spread Function | Modulation Transfer Function |
| Phase Transfer Function | Signal Transfer Function |
| Noise Power Spectrum | Root Mean Square Noise |
| Noise Equivalent Luminance | Noise Equivalent Radiance |
| Integrated Photometer | |
| F1′ Efficiency | <5% (photopic response accuracy) |
| Detector Head | 10 x 10mm silicon detector |
| Software/Controls | |
| Optikos I-SITE™ software package running on a Windows XP desktop computer | |
| Mechanical | |
| Optical Axis Height | 500mm (custom axis height upon request) |
| Dimensions | 15″ x 15″ x26″ (38 x 38 x 67cm) |
| Weight | 43 lbs. (20 kg.) |
Standard Equipment
- Source unit
- Power supply
- Control electronics
Optional Equipment
VLS-10 Photometer: Measures and displays source luminance. The photometer is calibrated in photometric units to NIST traceable standards.
Additional equipment will be necessary to support some of the measurements described. A typical test facility would also include a measurement device and a collimator. Control of the VLS is through a computer running software.Optikos can provide complete test systems to suit most requirements.
Optical Filters
| Part # | Function |
| OFA-10 | Photopic efficacy |
| OFA-20 | Daylight color conversion (5500 K) |
| OFA-30 | 546 nm narrow band filter |
| OFA-40 | RGB |
Target Sets
The patterns on target plate sets include slits, circular apertures and 4-bar targets. Target plate patterns may be fitted vertically, horizontally or at 45 degrees in the output port. Slits and large 4-bar targets are centered on separate plates.
TGS-20 Blank Target
| Type | Set | Dimension |
| Blank | 1 target on 1 plate | — |
TGS-30 Slit Target Set
| Type | Set | Dimension |
| Slit | 2 targets on 2 plates | 0.22 mm & 0.72 mm in width |
TGS-40 Circular Target Set
| Type | Set | Dimension |
| Circular | 22 targets on 5 plates | 0.4 mm – 18.25 mm diameter |
TGS-60 4-Bar Target Set
| Type | Set | Dimension |
| 4-Bar | 22 targets on 11 plates | 0.4 mm – 18.4 mm in periodicity |