Development of an Advanced 3D Cone Beam Tomographic System

Sire, Pascal; Rizo, P.; Martin, M.; Grangeat, Pierre; Morisseau, P.

doi:10.1007/978-1-4615-3344-3_46

Cited by 4 publications

(5 citation statements)

References 2 publications

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“…(1) (2) where a is the reconstructed spatial resolution and s is the source spot size [8]. This formula assumes that the object is sampled with sufficient angular sampling.…”

Section: Reconstructionmentioning

confidence: 99%

“…Data can be collected faster, albeit with less dynamic range, than with a linear detector array. An image intensifier coupled to a video camera is often used as the detector in a conebeam system [1,2]. This type of system offers high readout rates (up to 30 frames/sec ), but suffers from relatively low spatial resolution, 8-bit dynamic range, and image distortion from the image intensifier.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Conebeam Microtomography Using a Fiberoptic Scintillator and a Lens-Coupled CCD Camera

White

Roney

Galbraith

1997

Review of Progress in Quantitative Nondestructive Evaluation

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“…(1) (2) where a is the reconstructed spatial resolution and s is the source spot size [8]. This formula assumes that the object is sampled with sufficient angular sampling.…”

Section: Reconstructionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Conebeam Microtomography Using a Fiberoptic Scintillator and a Lens-Coupled CCD Camera

White

Roney

Galbraith

1997

Review of Progress in Quantitative Nondestructive Evaluation

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“…The following results have been acquired on the experimental bench EV A devoted to structural ceramics examination [15]. This experimental system consist of a HOMX161 IRT microfocus X-ray source, a precise tri-field image intensifier, and a SOFRETEC CCD camera.…”

Section: Experimental Data Reconstructionmentioning

confidence: 99%

51463 X-ray cone beam tomography with two tilted circular trajectories

Rizo¹,

Grangeat²,

Sire³

et al. 1994

NDT & E International

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Recently 3-D cone-beam tomography has become of interest for the nondestructive evaluation of advanced materials. The main field of application in nondestructive testing is the evaluation of structural ceramics. Study of such materials implies high density resolution and high sensitivity to cracks. In fact, with a single circular source trajectory, when the conebeam aperture increases, density is underestimated and cone shaped artifacts may appear at interfaces in the sampie even at relatively small aperture [1][2][3]. These artifacts limit the thiekness we can ex amine with a planar source trajectory. To maintain optimal reconstruction accuracy with a circular source trajectory, the angular aperture must remain within ±10 0 • However Kudo and Saito [4] showed that this limit can be slightly overcome by using a special interpolation of the shadow area. But to examine greater thicknesses and to maintain resolution, we must widen the cone-beam aperture thereby decreasing accuracy. To overcome these aperture limitations, Tuy [5] introduced the double circular source trajectory idea.Until now, most of the experiments presented in the literature were performed with a planar source trajectory [1,2,3,4,6]. Recently, a new method presented by Smith [7,8] has been applied to nonplanar source trajectories by Kudo and Saito [9]. The inversion presented by Kudo uses the Hilbert transform of the first derivative of the Radon transform. This inversion has been experienced with real data on two circular trajectories at 90° with intersection of the two axis of the trajectories (orthogonal scan).We have presented [10] reconstructions on simulated with double circular source trajectories with an exact reconstruction method using the inversion of the first derivative of the 3-D Radon transform. These simulations were performed with an angle smaller than 90° between the two trajectories. Here we quantify the advantages of this method and we present experimental reconstruction in this implementation. We show also that according to the Radon space sampling, the axes of the two trajectories do not have to intersect, but they must be close enough. MATHEMATICALBACKGROUNDGrangeat [11,12] showed that we can link exactly the X-ray transform of an object and the first derivative of its 3D Radon transform. Given an object function f(M) where M is a given point of the space, let us define the X-ray transform Xf(S,A), as the radiographie reading at point A corresponding to a source position S: +00Xf(S,A)= J f (S + a.u~)da with u~ = a = 0

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“…The first systems were based on an angiographic medicalline [1,2]. Most ofthem used an image intensifier and a high sensitivity camera.…”

Section: State Of the Artmentioning

confidence: 99%

“…where ~ll is the proportion of energy lost by an X-ray in the scintillating screen; Ex is the mean energy ofthe X-rays reaching the scintillating screen; W is the energy ofthe photon emitted by the screen; n1 is the light efficiency ofthe screen; Dopt is the proportion oflight which is transmitted by the lens; llcam is the quantum efficiency ofthe camera; Eopt is the proportion of light which is seen by the lens defmed by the following formula: (2) where fis the optical aperture ofthe lens and M is the demagnification ratio (ratio between the pixel size on the detector screen and on the CCD).…”

Section: State Of the Artmentioning

confidence: 99%