SNR-optimized image fusion for transparent object inspection

Author(s):  
Johannes Meyer ◽  
Wolfgang Melchert ◽  
Matthias Hartrumpf ◽  
Thomas Längle ◽  
Jürgen Beyerer
2016 ◽  
Vol 83 (12) ◽  
Author(s):  
Johannes Meyer ◽  
Thomas Längle ◽  
Jürgen Beyerer

AbstractTransparent materials are employed for creating different kinds of products and have to meet high quality requirements. First of all, transparent materials have to be free from scattering defects, e.g., enclosed air bubbles. Visual inspection systems based on dark field setups are principally capable of imaging these kinds of defects, however, it usually requires much effort to adapt them to the test object on hand. This article shows how light transport matrices can be calculated for an optical system consisting of a programmable area light source and a telecentric camera. Two features are proposed that can be extracted out of these matrices and that allow to image scattering defects present in a transparent object without the need of adapting the system to the actual test object. The results of synthetic experiments obtained using a physically based and adequately extended rendering framework approved the proposed approach and showed that it even outperforms classical inspection systems in some situations.


2005 ◽  
Vol 173 (4S) ◽  
pp. 414-414
Author(s):  
Frank G. Fuechsel ◽  
Agostino Mattei ◽  
Sebastian Warncke ◽  
Christian Baermann ◽  
Ernst Peter Ritter ◽  
...  

2004 ◽  
Vol 43 (03) ◽  
pp. 85-90 ◽  
Author(s):  
E. Lopez Hänninen ◽  
Th. Steinmüller ◽  
T. Rohlfing ◽  
H. Bertram ◽  
M. Gutberlet ◽  
...  

Summary Aim: Minimally invasive resection of hyperfunctional parathyroid glands is an alternative to open surgery. However, it requires a precise preoperative localization. This study evaluated the diagnostic use of magnetic resonance (MR) imaging, parathyroid scintigraphy, and consecutive image fusion. Patients, methods: 17 patients (9 women, 8 men; age: 29-72 years; mean: 51.2 years) with primary hyperparathyroidism were included. Examination by MRI used unenhanced T1- and T2-weighted sequences as well as contrast-enhanced T1-weighted sequences. 99mTc-MIBI scintigraphy consisted of planar and SPECT (single photon emission tomography) imaging techniques. In order to improve the anatomical localization of a scintigraphic focus, SPECT-data were fused with the corresponding MR-data using a modified version of the Express 5.0 software (Advanced Visual Systems, Waltham, MA). Results of image fusion were then compared to histopathology. Results: In 14/17 patients, a single parathyroid adenoma was found. There were 3 cases with hyperplastic glands. MRI detected 10 (71%), scintigraphy 12 (86%) adenomas. Both modalities detected 1/3 patients with hyperplasia. Image fusion improved the anatomical assignment of the 13 scintigraphic foci in five patients and was helpful in the interpretation of inconclusive MR-findings in two patients. Conclusions: Both MRI and 99mTc-MIBI scintigraphy sensitively detect parathyroid adenomas but are less reliable in case of hyperplastic glands. In case of a scintigraphic focus, image fusion considerably improves its topographic assignment. Furthermore, it facilitates the evaluation of inconclusive MRI findings.


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