Proc. SPIE. 9761, Emerging Digital Micromirror Device Based Systems and Applications VIII
KEYWORDS: Near infrared, Mirrors, Digital signal processing, Modulation, Video, Photography, Semiconductor lasers, Signal processing, Projection systems, Digital micromirror devices, Pulsed laser operation, Hardware testing, Digital Light Processing, Laser systems engineering
Near infrared (NIR) dynamic scene projection systems are used to perform hardware in-the-loop (HWIL) testing of a unit under test operating in the NIR band. The common and complex requirement of a class of these units is a dynamic scene that is spatio-temporal variant. In this paper we apply and investigate active external modulation of NIR laser in different ranges of temporal frequencies. We use digital micromirror devices (DMDs) integrated as the core of a NIR projection system to generate these dynamic scenes. We deploy the spatial pattern to the DMD controller to simultaneously yield the required amplitude by pulse width modulation (PWM) of the mirror elements as well as the spatio-temporal pattern. Desired modulation and coding of high stable, high power visible (Red laser at 640 nm) and NIR (Diode laser at 976 nm) using the combination of different optical masks based on DMD were achieved. These spatial versatile active coding strategies for both low and high frequencies in the range of kHz for irradiance of different targets were generated by our system and recorded using VIS-NIR fast cameras. The temporally-modulated laser pulse traces were measured using array of fast response photodetectors. Finally using a high resolution spectrometer, we evaluated the NIR dynamic scene projection system response in terms of preserving the wavelength and band spread of the NIR source after projection.
KEYWORDS: Video, Digital signal processing, Near infrared, Digital micromirror devices, Signal processing, Digital Light Processing, Projection systems, Video processing, Computer programming, Light sources
We designed and developed a system to project video scenes in the near‐infrared (NIR) band based on digital micromirror devices (DMD) and digital signal processors (DSP). The system deals with the integration and interfacing of different embedded systems both in the field of digital light processing (DLP) and digital signal processing. On the DLP side, we integrated DMD, NIR light source, and projection optics. The input video source for the dynamic scene was generated using a DSP, where we designed and implemented a fast video‐retrieval algorithm. The proposed system can be used for testing and design of equipments operating in the NIR band. The system is tested for projecting NIR video at different projection distances using different driving powers of the NIR laser source, and it operated correctly and was capable of producing high frame rate of 180 frames per second (fps) without delay or distortion when viewed by an NIR camera.