Coarse-Resolution Cone-Beam Scanning of Logs Using Eulerian CT Reconstruction. Part II: Hardware Design and Demonstration

Abstract

Computed Tomography (CT) provides an attractive opportunity in the wood industry for quality assessment of logs entering a sawmill to enable the material to be appropriately processed into maximum value products. A CT scanner suitable for this task must be simple and economical, considerably more so than the complex and costly scanners typically used for medical applications. Part I of this paper presented the design concept and the theory of operation of a specially designed coarse-resolution cone-beam CT scanner. This second part focuses on the CT system hardware design, construction and performance. Key components are a large-format custom-designed X-ray detector panel, a log spiral-motion mechanism and a real-time data acquisition system. These are described in detail. The coarse-resolution reconstruction results for an example log using feature-specific models and algorithms introduced in Part I of this paper are demonstrated and they compare well with CT reconstructions for same log using the same measurement with conventional filter back projection algorithm. The good comparison gives confidence in the usefulness and applicability of the proposed CT scanner design for industrial use in sawmills for log quality assessment.