SPx Radar Scan Conversion

High-performance, software-based radar scan-conversion

SPx-Scan, a component of Cambridge Pixel's SPx sensor processing family, is a new-generation COTS software component providing a high-performance, cost-effective radar scan-conversion capability for Windows and X11 graphical environments. For a basic introduction to radar scan conversion, see here.

SPx-Scan fully exploits the power of modern multi-core processors (for example Intel's Core 2 Duo and Core 2 Quad) and graphics processor units (GPUs), with their advanced general-purpose processors and rendering shaders.

With SPx-Scan you write the application software in Microsoft Windows or Linux X11, possibly using a third-party toolkit. SPx-Scan provides the radar scan-conversion module which creates the radar picture and handles display mixing with the graphics - all using low-cost, easy-to-maintain hardware.

Why Software Scan Conversion?

For many years, hardware-based radar scan conversion has been the only realistic solution to the display of high quality radar video. The development of higher performance graphics cards, combined with the availability of low-cost multi-core processors, has changed that. A modern software-based solution offers flexibility, performance and the ability to meet evolving requirements, all at a lower cost, and with higher reliability and ease of maintenance. By contrast, hardware scan-converters have a high-initial cost, high maintainance costs, and demand careful integration with the graphics hardware.

Flexible Display Formats

Interfacing to hardware or network streams, SPx-Scan accepts polar format radar video and converts into a number of possible display formats including PPI (Plan Position Indicator), A-Scan and B-Scan. See here for an explanation of the different  formats for radar scan conversion. SPx-Scan is a self-contained software module that can be targeted for a range of processing and display platforms, allowing radar imagery to be incorporated into a complex multi-layer graphics applications.

SPx-Scan operates on incoming radar video to create real-time updating images. These images are either available to application software to incorporate in displays as a bitmap layer, or else can be rendered directly onto the display with minimal cooperation from, and impact on, the application software. This ease of integration is a key feature of SPx-Scan.

Underlay/Overlay display Architectures

A feature of graphical applications for command and control, VTS or ATC is the need to display multiple layers of graphics information. One solution to this has been the development of special-purpose hardware graphics cards that support separate display layers for overlays and underlays. These provide a good solution, but the hardware architecture is often proprietary and expensive. With the latest generation of graphics architectures, the same multi-layering capabilities can be implemented in software to provide equivalent layering capability with more flexibility at a much reduced cost. The SPx software takes full advantage of modern processing and display architectures.  Applications can be built with underlays for maps and charts, radar video that is semi-transparently blended with the maps, and finally opaque overlays for overlay symbology. For more information on layering, see here

Flexible Configurations

Supporting either client-server based configurations, in which the scan-converter and the display are on different machines, or local applications where a single processor handles both, SPx-Scan is a highly flexible and configurable set of software components. From a Windows-based laptop through to a multi-computer Linux/X-Windows client-server configuration, SPx-Scan provides a single cross-platform solution for cost-effective radar video processing and display.

Multiple Display Channels 

A unique feature of SPx-Scan is its ability to display multiple channels of radar video simultaneously. This can represent multiple radars, for example located at different locations, but also can be used to show different videos from the same radar. These videos may be derived from the radar itself, or else may be computed by an SPx processing chain. For example, SPx can be used to identify moving targets in the input video by comparing current data with a time-averaged history. The data identified as changed can then be scan-converted in a different colour, providing display emphasis to an operator. Click here to download an application note that shows show SPx may be used to identify and display moving targets as an additional channel of radar video.

The automatic generation of a moving target indicator (MTI) by processing the video allows rapid identification of changes in the radar display images. In a complex, changing environment, such as an airport, for example, movement around the aircraft can very easily be seen in a color that contrasts with the normal video.

SPx-Scan Application Development

SPx-Scan provides an Application Programming Interface (API) to control the processing and presentation of the radar video. A small number of calls from the application software to the module are used to set-up and dynamically configure the operation. Changes to window size, scale or display presentation are effected in real-time, to help ensure that the radar component of the display stays synchronised to changes in the remaining graphics layers. Updates to the contents of the scan-converted bitmaps can be reported to the application software at a programmable rate through one of a number of software event mechanisms, or else SPx-Scan can directly update the screen itself to semi-transparently blend the radar video with the graphics. Either way, SPx-Scan supports real-time sector-based updates of the radar display or else lower frequency (quadrant or scans) as needed.

Extended Processing Capabilities

The SPx product family supports the addition of a number of radar processing modules to improve the presentation of the radar video. These include thresholding, filtering, clutter suppression and scan-to-scan integration. Optional recording capabilities are available in the compatible SPx-Record module that records the polar radar video to support, for example, for incident recording or training applications. For more information on SPx processing modules, see here

Cost-Effective - Uses low-cost, computing and graphics hardware

SPx-Scan is a cost-effective solution for radar processing and display. By eliminating the special purpose hardware in your system, both capital and maintenance costs are reduced. The same software solution can be run on a variety of computing platforms from laptops through to high-end multi-core, multi-processor servers.

SPx-Scan Summary Specifications

• Software radar scan-conversion
• Industry-leading performance - uses COTS hardware for processing and graphics
• PPI, B-Scan and A-Scan display
• Up to 256 levels of smooth fade
• Radars up to 120 rpm
• High accuracy conversion - full double-precision calculations with validated accuracy test results
• Multiple windows - limited only by hardware, so growth path assured
• Multiple radars in a window - multiple videos or different radars in the same window 
• Multiple colours - show different videos in different colours for clarity
• Hole-free, spoke-free - considers all source and all destination samples
• Trail retention on view change  - keeps display of trail history on view change
• Test pattern generator - flexible test and scenario generator module for testing
• Continuous zoom and centering - Fully programmable range scaling and view centering
• Real-time updates - Updates at display for real-time appearance of sweep
• Time-based or sweep-based fading - Flexible fading modes for balancing realism and CPU load
• C/C++ library - Easy-to-use C/C++ library for Windows or Linux/X11 support
• Cost effective - Offers significant cost-of-ownership savings against older hardware-based solutions
• Easy integration into application - Works with Windows and Linux/X11 graphics
• Highly configurable - Easy to use, but also flexible to accommodate special requirements
• Part of an integrated product family - Works with other SPx modules for radar capture, processing and distribution
• Windows + X11 Windows support
• Optional radar recording

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FREE Demo Software

Contact us to receive a fully working demonstration package showing SPx Software Scan Converter (PPI and A-Scan) in action. The software runs under Windows XP and provides a self-contained demonstration of radar scan-conversion overlaid on an S57 chart. The demonstration will run an a laptop computer, but a mid-range PC is recommended for best performance. The software demonstrates the capabilities of underlay and overlay windows combined with real-time radar video with smooth fading. Equivalent capability is available for Linux/X Wndows. Contact us if you are interested in that platform.

SPx-Scan Data Sheet

Download the SPx-Scan data sheet (pdf format) here.