Some UAV pilots have likened controlling an unmanned aerial vehicle to “flying an airplane while looking through a straw.” As the demand increases for greater visual awareness of the vehicle, and improved video for surveillance purposes, the burden on video capture and streaming electronics onboard the aircraft has ballooned.
New systems are adding more video sources, and increasing the image resolution from lower quality to high definition at increased frame rates. The result is up to 12 times more data per video stream. To make matters worse, communication links to and from the unmanned vehicle are often bandwidth-limited, so significant data compression is required to enable an operator to view even one video source at a control center.
To meet skyrocketing video processing demands, and at the same time satisfy continually declining size, weight, and power expectations, GE Intelligent Platforms undertook the task of designing a product for video streaming in a rugged unmanned vehicle environment.
The ICS-8580 module offers a range of features to meet the many often conflicting demands of this application; including ultra-efficient compression, scalability, SWaP characteristics, input flexibility and versatile codec settings. It supplies a combination of features, flexibility, video input support, low power, and small size that fits the needs of the unmanned vehicle market.
The module takes advantage of ITU-T H.264 (aka MPEG-4 part 10). This video standard was a joint effort between the International Telecommunications Union and the Motion Picture Experts Group. It was designed specifically to provide optimal motion video quality over a low bandwidth link – originally a telephone line, but now extends into Ethernet and wireless RF applications as well.
This standard takes advantage of the fact that not all information in a given frame changes from the previous frame. In fact, motion video, especially for live video camera inputs, provides significant frame-to-frame similarities. These similarities and redundancies can be leveraged to significantly increase compression performance with little or no impact on perception of video quality.
The compression ratios that can be attained by the H.264 codec, using motion vector tracking, can reach up to 100 or 150:1 while still maintaining good video quality. Thus, an HDTV (1920 x 1080 pixels) video stream, at 30 frames/sec, can be transmitted with as little as 5 to 10 Mbps of data bandwidth. If greater video degradation can be accepted, the video data rates can be reduced even further, bringing the required bandwidth down even below 1 Mbps in some cases.
Power dissipation is always a concern in the deployment of unmanned vehicle systems. The GE module with low power dissipative devices, typically consumes around 15 W of power for two 1080p30 HDTV inputs.
The video compression board can reliably achieve latencies of less than 75 ms, and below 50 ms in some cases. The board supports all legacy analog inputs including STANAG3350A/B/C, RS-170 RGB, Sync-on-Green modes, and all VESA VGA-type inputs, and newer digital formats such as DVI, HDMI, 3G-SDI, and even Ethernet.
GE’s ICS-8580 video compression unit provides many parameters that can be controlled from a remote client machine by an operator or supervisor. These parameters allow configuration of video quality, periodicity of completely encoded “I” frames, frame rate, and resolution, to name a few.
GE Intelligent Platforms
Filed Under: Aerospace + defense, Networks • connectivity • fieldbuses