2-D Wavelet Segmentation in 3-D T-Ray Tomography

Yin, Xiaoxia; Ng, Brian W.-H.; Ferguson, Bradley S.; Mickan, Samuel P.; Abbott, Derek

doi:10.1109/jsen.2006.890159

Cited by 27 publications

(19 citation statements)

References 6 publications

(7 reference statements)

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“…Both pulsed and CW THz waves can be applied to tomographic imaging of layer structure of tablets, internal structures of objects, material inspection, security applications, etc. [42,43,44,45,46,47,48] In addition to the above limited examples, a wide range of nondestructive inspection and testing applications have been reported in order to find real and specific needs which cannot be duplicated by competing technologies.…”

Section: Imagingmentioning

confidence: 99%

Terahertz technologies: present and future

Nagatsuma

2011

IEICE Electron. Express

184

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A number of technical breakthroughs in electronics and photonics made since the early 1990s have started to bring terahertz (THz)-wave technologies from laboratory demonstrators to industrial applications such as non-destructive testing, security, medicine, communications, etc. This paper overviews the latest progress in THz-wave technologies in terms of components such as sources and detectors, and system applications, and discusses future challenges towards market developments. Keywords: terahertz, source, detector, spectroscopy, imaging, communication Classification: Fiber optics, Microwave photonics, Optical interconnection, Photonic signal processing, Photonic integration and systems References[1] D. Grischkowsky, S. Keiding, M. van Exter, and Ch. Fattinger, "Farinfrared time-domain spectroscopy with terahertz beams of dielectrics and semiconductors,"

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Section: Imagingmentioning

confidence: 99%

Terahertz technologies: present and future

Nagatsuma

2011

IEICE Electron. Express

184

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“…It is based on the assumption that the image to be reconstructed belongs to an identifiable ensemble of similar images [20]. The filtered back projection algorithm is often used in the calculation of the inverse Radon transform [21]- [23], which reconstructs a target object from a collection of projections. Typically, the quantities obtained are the object's frequency dependent optical properties, such as the absorption coefficients.…”

Section: A An Overview Of Computed Tomographymentioning

confidence: 99%

Local Computed Tomography Using a THz Quantum Cascade Laser

Yin

Zeitler

et al. 2010

IEEE Sensors J.

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Abstract-This paper investigates local reconstruction techniques for extracting region-of-interest (ROI) from a 3-D terahertz imaging setup using a quantum cascade laser (QCL). The advantage of local reconstruction is the reduction in the required measurement time. Difficulties with limited projection angles and image noise make the development of accurate reconstruction algorithms particularly challenging. In this paper, both wavelet-based and traditional filtered back projection (FBP) techniques are investigated. Segmentation algorithms are applied to reconstructed images with low contrast and the resultant segments are compared with a known ground truth to explore the ability of a QCL to image target objects with complex contours. In our experiments, a polystyrene object with a hole drilled inside is used as the imaging target. The region of interest is adjusted through changing the size of the exposure regions. It is found that 3-D local reconstruction of the interior hole suffers from shape distortion, since scattering caused by the target's exterior contours introduces errors in the measured optical parameters of the object. It is found that wavelet-based local computed tomography for terahertz image reconstruction results in lower misclassification of pixels than traditional FBP algorithms.Index Terms-Computed tomography, discrete wavelet transforms (DWT), filtered back projection, fuzzy c-means threshold, quantum cascade laser (QCL), terahertz.

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“…Similarly, LOO evaluates each unknown feature vector, and then produces a basis to evaluate classifier designs for powder classification [7], [28]. Therefore, LOO accuracy is also the percentage of correctly classified data sets.…”

Section: Performance Assessment Of Classificationmentioning

confidence: 99%

“…T-rays have promising potential both in in vivo and in vitro biosensing applications [1]- [3] owing to: 1) their noninvasive property and 2) the fact that biomolecules have rich resonances in the T-ray region [4]- [6]. The ultimate aim of our work is to perform automatic classification of data obtained from T-ray measurements with tomographic applications [7]. It is important to devise effective feature extraction methods to fully represent the different characteristics of these signals [8].…”

Section: Introductionmentioning

confidence: 99%