Even if a factory inspection system doesn't need 3D stereo vision, the tool can simplify 2D image processing. Two synchronized 2D cameras can create stereo 3D images that help adjust for different heights or depths of objects going down the line or being guided on and off pallets. Combining stereo 3D with smart camera technology in a rugged handheld system, such as QuantumVision's Hammerhead, is a relatively new idea.
"In many applications, vision system engineers don't really care about the stereo 3D info, like robots with sophisticated 3D vision that already has much higher accuracy in the Z dimension than stereo 3D can provide," Robert Blenis, QuantumVision's CEO, told us. "But just having the 3D information available makes your 2D image processing a lot simpler."
The system calculates a 3D height map that's overlaid on the entire image. If engineers are imaging the known height of an object being picked up on a pallet, there may be other objects around it on the pallet. "3D stereo information lets you filter out the pixels that aren't in the height range you care about, so all that's left in the 2D image are the pixels you need," Blenis said. Left and right 2D camera images can also be accessed separately for additional processing.
The Hammerhead system measures 6 inches x 2.37 inches x 1.4 inches and includes two cameras mounted on a single board. Both CMOS imagers are clocked from the same chip, making synchronization easy. The cameras can be two 1.3-megapixel grayscale imagers, two 3.1-megapixel color imagers, or a custom version with two 5-megapixel color or grayscale imagers. They can have either the same lenses or lenses with different focal lengths. The interconnects of all versions are made through flexible connectors to enable multiple mechanical configurations or upgrades. A small heater is standard on all models for use in extreme cold temperatures, and a washdown version is optional.
QuantumVision originally developed the system as a custom OEM security system for tracking people. The company then decided to productize the system for security, industrial, and military uses, Blenis said. "In many applications, engineers need a bit more than some vision products can deliver. For example, a so-called barcode application may actually require more than barcode reading." In one case, a shipboard ammunition system had to identify correct ammunition for the gun. Vision hardware mounted in the gun's breech could do this, but the hardware had to withstand extreme temperatures, salt water, shock, and vibration. "That's no longer just a barcode reader."
The Hammerhead runs Linux 2.6 on the dual-core ARM CPU. The SDK supports development in C/C++ using the open-source GNU tool chain, as well as Python 2.6. Standard communication protocols such as FTP, HTTP, XML-RPC, Telnet, and SSH are supported. Systems come with a complete vision library. Typical 2D algorithms include 1D and 2D barcodes, linear measurement tools, and pattern matching.
QuantumVision is also developing standard application software packages for specific industries, Blenis said. For example, a robotic palletizing application would include 3D measurement tools for calculating 3D coordinates, as well as standard tools for blob and geometric pattern matching to locate objects. All packages include an SDK.
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