Aeon Imaging's Near Infrared (NIR) Projector couples an 860nm laser source to a Texas Instruments DLP® LightCrafter™ Evaluation Module. The result is a compact projection module, capable of:
- Up to 80mW power output
- >2,000:1 full-on full-off contrast
- Telecentric, zero offset output
- 4kHz pattern display rates
- Configurable I/O triggers for synchronization with external devices.
The NIR Projector is not a consumer electronic device or toy. The output is not easily visible, but still has high enough power to cause injury. Please contact us if you'd like to discuss using the NIR projector in research applications.
Project Live Images and Video in NIR
NIR Structured Light - Invisible to the naked eye
You may be asking yourself why anyone would want to project a display that can't easily be seen. One reason is for structured light imaging (SLI) applications. SLI analyzes how the image of an illumination profile changes to determine 3D depth information.
Look closely at the image of the checkerboard above and you'll see that it is slightly shifted sideways in the area over the hand as compared to the wall. These small shifts, measured by rapidly imaging a scene with various pre-set illumination patterns, are used to reconstruct a 3D profile of a target. When ambient room lighting is also picked up by the camera, the contrast of the structured illumination decreases, making it harder for the camera to detect changes in the illumination profile. Unless you plan to only use your 3D camera in the dark, you're going to want near infrared light.
Laser Illumination (NOT LEDs)
Visible light emitting diodes (LEDs) are often used in projectors since they provide relatively high brightness at low cost. Unfortunately, they are challenging to use in imaging systems due to their high etendue, which requires short optical path lengths and careful aberration correction.
Aeon's NIR Projector uses an 860nm vertical cavity surface emitting laser (VCSEL). These sources, commonly used for telecommunications, can be pulse-width modulated at 1kHz rates and have relatively low temporal coherence, which results in low speckle noise as compared to edge-emitting laser diodes. With a far lower etendue than LEDs, the NIR light can be efficiently coupled through the imaging system with lower aberrations and lower power loss.
Compatibility
Aeon's NIR Projector replaces the optical module of Texas Instruments' DLP LightCrafter EVM. All other components, including the drivers and open source API and user interface used to configure the DLP LightCrafter, remain the same, allowing you to quickly switch between visible and NIR illumination systems.
The NIR Projector also includes an Arduino-compatible microcontroller. Serial communication commands from software can be used to drive the illumination source, configure status LEDs and input/output triggers, and monitor the internal temperature.
Configure the indicator LEDs and input-output triggers for synchronization with external devices using the cross-platform Arduino® software (IDE).
Easily add your imaging system components on-axis to the projector output with Thorlabs'® 30mm Optical Cage System.
NIR Digital Light Ophthalmoscope (DLO)
The NIR Projector was initially developed for retinal imaging using the Digital Light Ophthalmoscope (DLO) under grants EY018772, 90BISA0004 and EY024186. In these projects, the subject retina and direction of gaze is recorded in real-time (at 15-25 fps) while vision research experiments can be performed simultaneously using visible light provided by a separate projector or LCD screen.
For ophthalmic imaging, NIR illumination has the general benefits of not being uncomfortable for patients (no bright lights) and does not constrict the pupil. These factors generally make retinal imaging sessions fast and easy on a wide range of the population.
DLP® and the DLP logo are registered trademarks of Texas Instruments Inc. Arduino® is a registered trademark of Arduino AG. Aeon Imaging LLC is not connected to Texas Instruments Inc or Arduino AG in any way.