GigE Vision for 3-D Medical Research

ThreeRivers 3D, a 3-D imaging device maker, has been commissioned by a major medical research center to develop a 3-D hand scanner. The purpose of the custom device is to scan patients’ hands to monitor the progression of rheumatoid arthritis by tracking volume changes and inflammation in affected joints over a period of time.

The scanning system designed by threeRivers 3D will help monitor the progression of rheumatoid arthritis by tracking volume changes and inflammation in patients’ joints.

Rheumatoid arthritis is a widespread autoimmune disease that attacks many tissues and organs, but principally affects synovial joints (hands, feet, knees and elbows), causing chronic inflammation as well as deformation. Rheumatoid arthritis affects millions of people of all ages worldwide. Although there is no known cure for the disease to date, medications to relieve symptoms and prevent joint destruction and deformity are widely available.

System overview

The 3-D hand scanner consists of an 80 × 60 × 40-cm metal frame with four posts, two high-speed 3-D laser scanners that project patterns on the patient's hand for the capture of image data, a color Prosilica GC1290C camera fitted with a standard 10-mm Edmund Optics fixed lens to monitor joint deformation, and a thermal camera that measures inflammation in the joints. Each 3-D laser scanner contains a monochrome Prosilica GC1290 camera fitted with standard 8-mm Edmunds Optics fixed lenses to capture the projected laser patterns. The system also is equipped with a thermal reference device near the palm rest. The device measures the ambient temperature to calibrate the system for accurate measurement of the temperature of a patient’s hands.

The Prosilica 1.3-megapixel cameras, which are made by Allied Vision Technologies, output uncompressed real-time images over a Gigabit Ethernet (GigE) interface. They feature the Sony ICX445 ExView HAD CCD sensor for high sensitivity and excellent image quality. ThreeRivers 3D selected the Prosilica GC1290 series for its compact size, which allows flexible mounting orientations; for its high dynamic range and spectral response, which facilitate the use of eye-safe lasers for the capture of 3-D images in ambient room lighting; and for advanced triggering options for synchronized scan data capturing. Several system peripherals also were driven through the camera’s RS232 port for increased functionality. In addition, the GigE Vision output provides a fast and reliable platform for the transfer of image data.

3-D rendition of hands

Both the Prosilica GC1290C and the thermal camera are mounted at the top of the frame, looking down at the target (i.e., the palm rest where the patient will place his/her hand). The two laser scanners and their internal Prosilica GC1290 cameras are set up on the side of the structure at 45°.

Each scanner projects a series of 50 patterns that help capture image data to create a 3-D image of the patient’s hand. Each 3-D rendition is captured in <5 s to ensure optimal quality and minimize issues such as blurring resulting from patient movement.

An artist’s rendition of threeRivers 3D’s hand-scanning device.

Once captured, the 50 images are processed by the system’s computer to create a 3-D rendition of the patient’s hand based on a sophisticated analysis of the shape of patterns and pattern variations captured.

The software was developed using Allied Vision Technologies’ PvAPI software development kit. Thanks to its extensive dynamic-link library, the kit can be developed directly into the application, which means that the system scanners can be deployed “driverless,” simplifying both the initial installation and long-term maintenance of client software. In addition, the kit is available for a wide variety of operating systems such as Windows, OS X, QNX and Linux. This allowed threeRivers 3D to use a common code repository to deploy scanners on all major operating systems.

The future for 3-D imaging

Currently the majority of 3-D processing is done using manual techniques. With the rapid growth of 3-D imaging for industrial uses, threeRivers 3D is developing automated 3-D custom scanners for the manufacturing, quality control and scientific industries that can capture and analyze data from thousands of 3-D scans automatically, greatly reducing labor and increasing throughput and accuracy.

For more information, visit: www.3rivers3d.com