TY - CONF A1 - Wieder, Frank A1 - Ewert, Uwe A1 - Vogel, Justus A1 - Jaenisch, Gerd-Rüdiger A1 - Bellon, Carsten T1 - A Novel Multi Slit X-Ray Backscatter Camera Based on Synthetic Aperture Focusing T2 - 43rd Annual review of progress in quantitative nondestructive evaluation N2 - A special slit collimator was developed earlier for fast acquisition of X-ray back scatter images. The design was based on a twisted slit design (ruled surfaces) in a Tungsten block to acquire backscatter images. The comparison with alternative techniques as flying spot and coded aperture pin hole technique could not prove the expected higher contrast sensitivity. In analogy to the coded aperture technique, a novel multi slit camera was designed and tested. Several twisted slits were parallelly arranged in a metal block. The CAD design of different multi-slit cameras was evaluated and optimized by the computer simulation packages aRTist and McRay. The camera projects a set of equal images, one per slit, to the digital detector array, which are overlaying each other. Afterwards, the aperture is corrected based on a deconvolution algorithm to focus the overlaying projections into a single representation of the object. Furthermore, a correction of the geometrical distortions due to the slit geometry is performed. The expected increase of the contrast-to-noise ratio is proportional to the square root of the number of parallel slits in the camera. However, additional noise has to be considered originating from the deconvolution operation. The slit design, functional principle, and the expected limits of this technique are discussed. T2 - 43rd Annual Review of Progress in QNDE CY - Atlanta, GA, USA DA - 17.07.2016 KW - Deconvolution KW - Back scatter imaging KW - Computer simulation KW - Aperture focusing PY - 2017 SN - 978-0-7354-1474-7 DO - https://doi.org/10.1063/1.4974711 VL - 1806 SP - 1 EP - 9 PB - AIP Publishing AN - OPUS4-42429 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaenisch, Gerd-Rüdiger A1 - Wieder, Frank A1 - Bellon, Carsten A1 - Ewert, Uwe A1 - Vogel, Justus A1 - Kolkoori, Sanjeevareddy A1 - Zscherpel, Uwe T1 - Back scatter X-ray imaging with twisted slit collimator – quantitative simulation and comparison to experiments N2 - X-ray backscatter imaging is a well-established NDT technique to inspect complex objects using only a single-sided access. We present a specially designed multi-slit scatter camera consisting of several twisted slits which are parallelly arranged in a metal block. The camera projects one image per slit to the digital detector array, where the images are overlaying each other. The aperture is corrected based on a deconvolution algorithm to focus the overlaying projections into a single representation of the object. In order to achieve high backscatter intensities from an object, it is necessary to optimize the parameters of the backscatter system by simulation. T2 - 2017 Far East Forum on Nondestructive Evaluation & Testing CY - Xi`an, China DA - 21.06.2017 KW - Back scatter imaging KW - Computer simulation KW - Aperture focusing KW - Deconvolution PY - 2017 AN - OPUS4-42084 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -