Taking video display/distribution further: Getting to 360 degree situational awareness
StorySeptember 10, 2010
Steve Edwards
Curtiss-Wright
The High Definition (HD) video commercial market has increased the number of camera and sensor types and the resolution of flat-panel displays. In turn, this has motivated designers of video distribution systems for military ground vehicles to seek ways to deliver 360? Situational Awareness Systems (360? SASs) while respecting the Size, Weight, and Power (SWaP) limitations of existing ground-vehicle platforms.
The High Definition (HD) video commercial market has increased the number of camera and sensor types and the resolution of flat-panel displays. In turn, this has motivated designers of video distribution systems for military ground vehicles to seek ways to deliver 360° Situational Awareness Systems (360° SASs) while respecting the Size, Weight, and Power (SWaP) limitations of existing ground-vehicle platforms.
360° SAS increases safety, efficiency
360° SAS will enable crew members to safely “see” outside the vehicle regardless of external environmental conditions. It enables multiple viewpoints to be extracted from different sensors and enhanced with sophisticated recognition technology to support tracking, identification, classification, and target alerts to minimize the user workload and speed operational responsiveness.
From thumbnails to HD panorama
Today’s ground vehicles typically have up to six video cameras from which the operator must manually select a primary input. The remaining video channels are represented with low-resolution thumbnail screens in a tiled or picture-in-picture format. True 360° SAS replaces this approach with a single panoramic high-resolution video image that can be panned horizontally and vertically in a natural fashion. 360° SAS adapts to the natural way that human operators view a scene and enhances that view with video fusion technology, overlaying a variety of sensor types on top of the visible light display (such as infrared and low-light cameras) to optimize the visual data being displayed.
Today’s video systems typically use cameras generating relatively low-resolution images at 640 x 480 or 1,024 x 768 pixels, compared with the 1,920 x 1,080 pixels of HD video. When the number of cameras and sensors needs to grow from a simple 2 or 3 up to 8 or 16, viewing and selecting channels from small thumbnail views quickly becomes impractical.
Using COTS to get to 360°
Seamless pan-and-tilt, panoramic displays require large amounts of compute processing, which today’s ground vehicles lack, to correctly register the image streams together. Fortunately, the emergence of small form factor, high-bandwidth, open standard-based COTS boards such as Curtiss-Wright Controls Embedded Computing’s (CWCEC’s) 3U VPX SBCs and the XMC-280 (Figure 1) video compression mezzanine cards can deliver much-needed multiprocessor compute power; they also provide the ability to distribute multiple channels of uncompressed high-definition video over VPX’s 32 Gbps switching fabric and XMC’s PCI Express mezzanine multilane data bus. Combined with a video distribution and archival system, such as CWCEC’s Sentric 2 software suite, powerful modular systems can be built to meet the demanding requirements of a 360° SAS.
Figure 1: The XMC-280 multichannel HD video compression card from CWCEC
(Click graphic to zoom by 1.4x)
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Another powerful component of 360° SAS is video fusion. Vendors today are developing algorithmic solutions for automatic motion detection to alert an operator when an activity of interest is captured by a camera. Video fusion going forward promises to mix technologies such as night vision, passive systems such as long-wave infrared, range laser-based systems, acoustic detection, and passive millimeter wave radar capable of penetrating through sand, fog, and dust. In order of increasing complexity and processing requirements, the fusion tasks include movement detection, image tracking, and object recognition. Object recognition is the most complex because it typically requires databases of image types, and the object in question must be filtered from the background.
The most significant practical challenge to bringing 360° SAS to ground vehicles today is the limited available space and the existing thermal envelope. In the short term, many of the components of 360° SAS can be achieved using COTS card-based products that vendors offer today. They can effectively bridge the divide between HD video and the quantity of data that can realistically be distributed over Ethernet.
Bandwidth is key
As the number of sensors and displays rises and the move to HD video accelerates, the bandwidth available from today’s Ethernet networks quickly becomes overwhelmed. In the consumer world and broadcast industry, standards such as 3G-SDI (SMPTE 424M) – providing 3 Gbps of serial digital video transmission over ordinary coaxial cable – are making the expectation of HD commonplace. Gigabit Ethernet (GbE) is unable to handle bandwidth beyond standard definition video unless it is compressed. Video compression helps, typically allowing eight channels of full HD video to be sent over a single GbE connection. Latency can cause unacceptable delays for real-time video distribution between targets on the battlefield and their display on screen; 100 ms of latency for a vehicle traveling 60 mph can impose a 10-foot disparity between the actual and displayed location.
Today’s standards and products are a start
Today system designers have to make compromises and trade-offs because legacy networks and processors are unable to deliver the ideal video and sensor functionality and performance. However, the use of current HD video acquisition and compression COTS products, combined with increasingly powerful processing and graphics hardware, will support the multiple-channel, high-resolution video requirements of 360° SA systems.
To learn more, e-mail Steve at [email protected].
