Quaternary pulse width modulation based ultra-high frame rate scene projector used for hard-ware-in-the-loop testing

Area of Science:

• Optical engineering
• Image processing
• Simulation technology

Background:

• Scene projectors (SP) are crucial for hardware-in-the-loop (HWIL) testing of imaging systems.
• Existing single scene generation device (SGD) based SPs project at 220 fps, insufficient for ultra-high frame rate applications like star trackers.

Purpose of the Study:

• To develop an ultra-high frame rate scene projector (SP) exceeding current limitations.
• To improve grayscale modulation efficiency for advanced imaging system simulations.

Main Methods:

• Developed a quaternary pulse width modulation (PWM) based SP.
• Utilized two digital micro-mirror devices (DMDs) in parallel with optically overlapped modulation layers.
• Employed quaternary digit-plane decomposition (QDD) to convert 8-bit images into four quaternary digit-planes (QDs).
• Controlled QD exposure time via quaternary PWM with an optimized base time of 8 µs.

Main Results:

• Achieved projection of 8-bit images at 1300 fps, a significant increase from 220 fps.
• Demonstrated a total exposure time of approximately 760 µs for all QDs.
• Showcased dramatically improved grayscale modulation efficiency compared to existing technologies.

Conclusions:

• The quaternary PWM approach offers a novel solution for designing ultra-high frame rate scene projectors.
• This technology enhances simulation capabilities for demanding imaging systems.
• The developed SP provides a new pathway for advancing HWIL simulation testing.