Evaluation of an automatic system for detection and positioning of small pore defects using digital radiography

Lindgren, Erik; Hammar, Lars

doi:10.1063/1.4789239

Cited by 3 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The CNR is approximately around 2. The setup geometry as indicated in Figures 1 and 5 is derived using the same procedure, settings, and calibration sample as in [33]. In short, a block of plastic with five ball-bearing steel balls (diameter 0.5 mm) cast inside at different depths and y-z positions is measured with a CT metrology system.…”

Section: Resultsmentioning

confidence: 99%

“…For the DR case, the points consisted of 0.5-mm high-tolerance ball-bearing steel balls, which the algorithm was set up to detect and position. The algorithm parameter values were the same as the for the calibration procedure described in [33] Volume Graphics. Additionally, the diameter and 3-D position of each detected pore are also measured manually in the visualization program.…”

Section: Resultsmentioning

confidence: 99%

“…The sample is then inspected with the same radiographic setup as will later be used for the algorithm. The steel balls are detected, and an evolutionary algorithm is used to derive a setup geometry parameter set from the known steel ball interspacing positions in 3-D. For details, see [33]. A setup geometry was derived and verified to give approximately 0.1-mm maximum positioning errors.…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Detection, 3-D positioning, and sizing of small pore defects using digital radiography and tracking

Lindgren

2014

EURASIP J. Adv. Signal Process.

Self Cite

View full text Add to dashboard Cite

This article presents an algorithm that handles the detection, positioning, and sizing of submillimeter-sized pores in welds using radiographic inspection and tracking. The possibility to detect, position, and size pores which have a low contrast-to-noise ratio increases the value of the nondestructive evaluation of welds by facilitating fatigue life predictions with lower uncertainty. In this article, a multiple hypothesis tracker with an extended Kalman filter is used to track an unknown number of pore indications in a sequence of radiographs as an object is rotated. Each pore is not required to be detected in all radiographs. In addition, in the tracking step, three-dimensional (3-D) positions of pore defects are calculated. To optimize, set up, and pre-evaluate the algorithm, the article explores a design of experimental approach in combination with synthetic radiographs of titanium laser welds containing pore defects. The pre-evaluation on synthetic radiographs at industrially reasonable contrast-to-noise ratios indicate less than 1% false detection rates at high detection rates and less than 0.1 mm of positioning errors for more than 90% of the pores. A comparison between experimental results of the presented algorithm and a computerized tomography reference measurement shows qualitatively good agreement in the 3-D positions of approximately 0.1-mm diameter pores in 5-mm-thick Ti-6242.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Detection, 3-D positioning, and sizing of small pore defects using digital radiography and tracking

Lindgren

2014

EURASIP J. Adv. Signal Process.

Self Cite

View full text Add to dashboard Cite

show abstract

“…The different images were analyzed to extract the necessary geometrical information for 3D reconstruction. A detailed description of the experimental setup and similar techniques for reconstruction are reported elsewhere [3]. Thereafter the rail head was cut at known positions along the rail, perpendicular to the rail centerline.…”

Section: Methodsmentioning

confidence: 99%

3D characterisation of RCF crack networks

Ahlström

Jessop

Hammar

et al. 2014

MATEC Web of Conferences

Self Cite

View full text Add to dashboard Cite

Abstract. Rolling contact fatigue (RCF) damage is becoming more frequent with increased traffic and loading conditions in the railway industry. Defects which are characterized by a two-lobe darkened surface and a V-shaped surface-breaking crack are often so-called squats. The origination and propagation of squats in railway rails is the topic of many recent studies; the associated crack networks develop with complicated geometry near the surface of rails that is difficult to characterise using most non-destructive methods. The cracks can be examined with repeated metallographic sectioning, but the process is time-consuming and destructive. In order to reduce time, as well as information and material loss, high-resolution and high-energy X-ray imaging of railway rails was done in the current study. Combining the exposures from a range of angles using image analysis, a 3D representation of the complex crack network is achieved. The latter was complemented with metallographic sectioning to determine the accuracy of prediction of the geometrical reconstruction.

show abstract

Detection and 3-D positioning of small defects using 3-D point reconstruction, tracking, and the radiographic magnification technique

Lindgren

2015

NDT & E International

View full text Add to dashboard Cite

Evaluation of an automatic system for detection and positioning of small pore defects using digital radiography

Cited by 3 publications

References 0 publications

Detection, 3-D positioning, and sizing of small pore defects using digital radiography and tracking

Detection, 3-D positioning, and sizing of small pore defects using digital radiography and tracking

3D characterisation of RCF crack networks

Detection and 3-D positioning of small defects using 3-D point reconstruction, tracking, and the radiographic magnification technique

Contact Info

Product

Resources

About