Video Processing Unit
The Video Processing Unit (VPU) is an auxiliary processor that combines cameras inputs in order to provide the operator functionality to select a single view or tile multiple views to optimize the operator’s situational awareness.
The Video Processing Unit (VPU) is an auxiliary processor that combines cameras inputs in order to provide the operator functionality to select a single view or tile multiple views to optimize the operator’s situational awareness. The video inputs (2 NTSC analog, 5 HDSDI digital) are passed through the VPU and fed to the main processing unit (MPU) without modification.
The Video Processing Box is implemented with an FPGA to handle all the video stream data. The FPGA accepts two BT.656 video streams from analog NTSC decoders and five HD-SDI digital video input streams. It crops, scales and overlays each of the video inputs onto a single mosaic VGA output driving an NTSC encoder. The Video Processing FPGA utilizes a 64-bit DDR3 memory interface operating at 350MHz for video buffering. The Video Processing FPGA includes a soft-core processor to handle command, control, and configuration of the FPGA operations.
To ensure a high-quality design, we performed numerous signal integrity and FPGA design simulations using our Mentor Graphics toolchain. Mentor’s HyperLynx was used to simulate the high-speed signal paths for signal integrity analysis, and ModelSim was used to verify the high-performance FPGA design prior to integration with the platform circuit card assembly.
The software running on the soft-core processor operates without an RTOS, and performs the following operations:
- Receives commands from the MPU over RS-485
- Zoom, resize, reposition any of the 7 video inputs
- Command the digital cameras to adjust parameters such as white balance and infrared (night vision) controls
- Stores up to 16 different configurations to quickly switch between different operator-customized video modes
- 24-layer PCB design
- MIL-STD-1275 and MIL-STD-461 power conditioning circuitry
- DDR3 memory interface
- Communications interface to the MPU via RS-485 for command/control and separate interface for video stream