Enhanced high-spatial resolution radiographic images based on COTS CMOS image sensors applied to wood dendrochronology and densitometry

DAMIAN LEONEL CORZI; JOSE LIPVOETZKY; FABRICIO PABLO ALCALDE BESSIA ET AL

RADIATION MEASUREMENTS

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2024 vol. 172

1350-4487

The imaging of wood samples using X-rays for the study of dendrochronology and densitometry is predomi-nantly conducted through analog films subsequently digitized or, in more advanced instances, with expensiveflat-panel systems characterized by resolutions on the order of tenths of microns. For this reason, this workproposes as an alternative the utilization of Commercial-Off-The-Shelf (COTS) complementary metal–oxide–semiconductor (CMOS) image sensors as affordable direct detectors for the acquisition of 10.2 μm resolutionradiographic images, which represents sufficient resolution to observe the small structures formed by woodcells called tracheids. The raw images are subsequently processed to mitigate the impact of non-uniformitiesinherent in pixel response, including the total dose effects, and artifacts present in the image generated byirregularities and defects in the materials utilized to support the wood samples. Moreover, an exhaustive studyof the sensor response over different x-ray tube voltage was performed, comparing the results obtained witha simple calculation model and finding a negligible contribution of the photons above the 20 keV. The modelwas developed based on diverse analyses of geometry and composition of the sensor, such as Focus Ion Beam,Scanning Electron Microscopy, and Time-of-Flight Secondary Ion Mass Spectrometry, and takes into account theX-ray beam attenuations and the photon interaction with the sensor. Finally, this model enables the estimationof the transmission based on the density and thickness of the wood samples.