If large volumes or several object views are to be checked automatically by 3D cameras, e.g. on constantly running production lines in the automotive industry, high-resolution 3D result data must be generated and processed quickly. Stereo camera systems with large 5 MP sensors and variable baselines provide the ideal output data. However, interfaces and CPU power can quickly form the bottleneck in such high-performance 3D applications. The challenge: to reduce data rates and performance requirements on system components without compromising data quality. At the same time, the systems should be space-saving and efficient. Embedded 3D cameras of the new Ensenso XR series from IDS Imaging Development Systems with integrated data processing are therefore the next logical step.

In machine vision applications with 3D cameras that work according to the principle of spatial vision (stereo vision), camera images are processed with high resolution and frame rates in order to make result data available to further processes as quickly as possible. The calculation of the three-dimensional data, so-called “point clouds”, from the image material of the stereo cameras requires several complex process steps, which were previously performed by powerful industrial PCs (IPCs). With increasing demands regarding the quality and speed of these result data, modern 3D stereo cameras, such as the Ensenso X series, use high-resolution 2D cameras with Gigabit Ethernet interfaces. However, the transmission of the 2D output data to the processing IPC requires optimally utilizing the network bandwidth in order to avoid time delays or data loss. In addition to that, the processing power of the IPC hardware must constantly increase in order not to restrict the overall system.

The Ensenso XR camera series is pursuing a different approach. A SoC (System-on-Chip) integrated in the Ensenso XR projector unit enables the camera to perform 3D processes including stereo analysis itself. Once the lens distortion has been corrected, the 2D output images are transferred to an axis-parallel stereo system by a virtual rotation of the cameras (rectification), which greatly simplifies all subsequent analyses. The highly optimized matching algorithms for static and moving scenes then search the recorded image pairs for corresponding pixels. Because of the different perspectives of the cameras, these pixels also show different horizontal shifts in the image plane (“disparity”). Due to the geometric relationships in the parallel stereo system, this disparity represents a measure of the spatial depth of a 3D point in millimetres after the application of beam sets and knowledge of known system parameters such as focal lengths, pixel sizes and the base length of the stereo system.

These time- and computation-intensive pixel operations are performed in parallel by a supporting FPGA in the camera. This allows a 3D data rate to be realized that is comparable to that of an Ensenso X system that performs stereo analysis on a desktop PC with an Intel Core i7 Quad CPU. By shifting the computation-intensive processes to the camera, they no longer have to be performed by powerful industrial PCs. In addition, the transfer of 3D result data instead of high-resolution 2D raw data reduces the network load. This makes the Ensenso XR camera ideal for multi-camera systems. Furthermore, the Ensenso XR projector unit has an integrated front light. When in use, it supports the calibration of the working environment or improves the image quality of the 2D camera images if the ambient light is insufficient or no external lighting is available.

With fast, direct memory access between image acquisition and processing, this application for high-resolution 3D data offers enormous advantages in terms of result rate and bandwidth reduction compared to external processing on an industrial PC. The powerful 3D cameras are distributed by IDS Imaging Development Systems. The Ensenso selector on the IDS website helps you to choose the right model.

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IDS Imaging Development Systems Limited

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RG27 9HA Hook

United Kingdom

Phone:  +44 1256 962910

uksales@ids-imaging.com

www.ids-imaging.com