Application of Two-Dimensional Matched Filters to X-Ray Radiographic Flaw Detection and Enhancement

Defect detection in partially completed SAW and TIG welds using online radioscopy and image processing

“…However, no single filter is suited to the automatic detection of all different flaw types, since variations in defect shape, grey level intensity, edge attributes, orientation, and position in the component make it very difficult to produce a generic defect model. Both Inoue and Sakai (1985) and Wallingford et al (1992) describe the use of matched filters for flaw enhancement and detection in weld and simulated images respectively. The method is based on the optimisation of signal to noise ratios (SNRs) given the expected two dimensional signature of a particular flaw.…”

The automated detection algorithm of coronal loop and statistical analysis of its width

“…的横切面温度分布情况, Aschwanden等人 [8] 使用OC-CULT算法自动检测了AIA/SDO图像中的570条冕环, 并对这些冕环的横切面温度分布进行了自动分析和统 计, 进一步验证了冕环横切面温度接近等温分布的结 论 [7] . 为了使用更大的样本研究冕环的横切面宽度分 布情况, Aschwanden和Peter [9] 使用OCCULT算法自动 检测和统计分析了AIA/SDO和Hi-C中的大量冕环宽度, 得到了最频繁的冕环宽度分布于550 km的结论, 这一 结论也进一步证实了Brooks等人 [10] 和Peter等人 [11] [2,4], [4,6], [8,10], [16,18] [18,19] . :…”

Use of an X-Ray Process Model to Determine Crack Detectability in a Multi-Layer Geometry

“…In cases where regions on the film are underexposed or overexposed, digital image processing techniques can be used to produce a digitized radiograph having a background density for optimum viewing. In addition, image enhancement techniques can increase critical flaw signals in low contrast, high noise conditions [2,3]. Once the radiograph is digitized,we can apply statistical tests based on the known noise characteristics of the measurement process to determine the statistical significance of potential flaws.…”

“…;.o::c;i::::.Be:;.......,--r~~-"""" If we consider all of the thresholding operations within the window together, the resulting number of thresholded pixels is governed by the binomial distribution and is given by (3) where nw is the number of thresholded pixels and A is the total number of pixels. The hypothesis test can now be stated as…”