Retrospective correction of the heel effect in hand radiographs

A method for the retrospective correction of intensity inhomogeneities induced by the heel effect in digital radiographs is presented. The method is based on a mathematical model for the heel effect derived from the acquisition geometry. The model parameters are estimated by fitting the model to the image intensity data in the background or direct exposure area only where the heel effect is directly measurable, while the correction is then applied to the whole image. The method iterates between background segmentation and heel effect correction until convergence. We illustrate the performance of the method on flat field and phantom images and demonstrate its robustness on a database of 137 diagnostic hand radiographs.

[1]  David Sinclair,et al.  Automatic segmentation of hand-wrist radiographs , 1993, Image Vis. Comput..

[2]  L T Niklason,et al.  Automated segmentation of regions of interest on hand radiographs. , 1994, Medical physics.

[3]  Jack Sklansky,et al.  Finding circles by an array of accumulators , 1975, Commun. ACM.

[4]  Paul Suetens,et al.  Evaluation of image features and search strategies for segmentation of bone structures in radiographs using Active Shape Models , 2002, Medical Image Anal..

[5]  Paul Suetens,et al.  Active Shape Model-Based Segmentation of Digital X-ray Images , 1999, MICCAI.

[6]  Viergever,et al.  Retrospective shading correction based on entropy minimization , 2000, Journal of microscopy.

[7]  Dana H. Ballard,et al.  Generalizing the Hough transform to detect arbitrary shapes , 1981, Pattern Recognit..

[8]  P. Suetens,et al.  Statistical shape model-based segmentation of digital X-ray images , 2000, Proceedings IEEE Workshop on Mathematical Methods in Biomedical Image Analysis. MMBIA-2000 (Cat. No.PR00737).

[9]  Koenraad Van Leemput,et al.  Automated model-based bias field correction of MR images of the brain , 1999, IEEE Transactions on Medical Imaging.

[10]  Paul Suetens,et al.  Retrospective Correction of the Heel Effect in Hand Radiographs , 2001, MICCAI.

[11]  F. Maes,et al.  Retrospective heel effect correction in conventional radiography , 2001, Proceedings IEEE Workshop on Mathematical Methods in Biomedical Image Analysis (MMBIA 2001).

[12]  S L Fritz,et al.  A comparison of computed and measured heel effect for various target angles. , 1982, Medical physics.

[13]  Pieter Vuylsteke,et al.  Multiscale image contrast amplification (MUSICA) , 1994, Medical Imaging.

[14]  John A. Nelder,et al.  A Simplex Method for Function Minimization , 1965, Comput. J..