Wood Log Internal Quality Scanning via Helical Tomography
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Solution Overview
Problem
Current methods for scanning the internal quality of wooden elements, such as logs, either provide high resolution but are time-consuming or are fast but lack detection of certain features like cracks, and are costly due to the use of large sensor matrices and cone-beam techniques.
Innovation Solution
A method employing a wide-helix rotary tomographic scan with reduced angular coverage and fewer readings, utilizing a combination of tomographic readings and a priori information to detect features that remain constant over significant axial lengths, such as cracks and decaying zones, with a detector and beam configuration that minimizes detection angles and increases scanning speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a rotary tomograph rotates about the log and takes multiple readings at different angular positions to obtain high resolution, then measurement precision is improved, but loss of time increases significantly
Solution Approach 1:
The patent applies partial action by taking fewer readings than a complete rotary tomograph would require. Specifically, it uses readings from only a subset of angular positions (e.g., 4-8 fixed sources instead of continuous rotation with many more measurement points) to detect constant features, thereby reducing scan time while maintaining sufficient precision for detecting features that remain substantially constant over predetermined axial lengths
2Productivity
If multiple fixed sources are used to speed up detection operations, then productivity is improved, but measurement precision deteriorates because only several types of very local defects can be detected
Solution Approach 1:
The patent applies preliminary action by incorporating a priori information about the constant nature of certain wooden features (cracks, decaying zones, growth rings) into the detection process. This allows the system to use fewer fixed sources with reduced angular coverage while still achieving reliable detection of these constant features, thereby maintaining both speed and precision
3Productivity
If cone-beam technique with large matrices of sensors is used to achieve rapid scanning, then productivity is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent extracts and uses only the essential information needed for detecting constant features, rather than employing complex large-matrix sensor systems. By focusing on features that remain substantially constant over axial lengths and using a priori information, the system achieves rapid scanning with simpler, fewer sensors arranged in fixed sources, eliminating the need for complex cone-beam hardware
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for high-speed detection of features that conventional systems miss, maintaining resolution in transverse directions while reducing axial resolution, thus optimizing the detection of constant features like growth rings and cracks, while keeping production and operating costs comparable to fixed source systems.
Implementation Method 1
irradiating the wooden element with at least one beam of electromagnetic radiation... detecting the residual intensity of the electromagnetic radiation which has passed through the wooden element
Data Source
AI summary
A method for scanning the internal quality of wooden elements (1) such as logs or planks comprises the operating steps of irradiating the wooden element (1) with at least one beam (3) of electromagnetic radiation according to one or more directions of irradiation which are transversal to the main axis of extension, at the same time creating a relative helicoidal movement between the wooden element (1) and the beam (3). During the movement, for a plurality of separate reciprocal positions of the wooden element (1) and the beam (3), the residual intensity of the electromagnetic radiation which passed through the wooden element (1) is detected for a detection length (L). The relative movement is created in such a way that the helix has a pitch P equal to Y times the sum of the detection length (L) of all of the detectors used, where Y≧5. Moreover, reconstruction of the internal structure of the wooden element (1), at a cross-section of it, is at least implicitly performed by dividing the volume of the wooden element (1), at the section to be reconstructed, into a plurality of basic volumes having a dimension along the main axis of extension which is equal to at least X times the detection length (L) of each detector used, where X≧5.