Research Output
Fringe projection profilomentry for phantom breast surface examination with progressive artificial tumour
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Publication
Breast tumour whether malignant or benign is harmful and one of the most feared tumour among women. Currently the common imaging modality for breast tumour diagnose is the ultrasound and mammogram. There are advantages and limitations of using the mammogram and ultrasound in terms of procedure of the process and its non-invasiveness. In this study a digital fringe projection system is developed to identify the phantom breast surface changes in terms of pixel coordinate and maximum breast height changes caused by the presence of artificial tumour. The system applies fringe patterns based on the three step phase shift projection. The fringe projection system utilizes a computer, LCD projector for non-parallel light illumination and CCD camera as means of image acquisition. Silicon catheter and metal screw were applied as artificial breast tumours with a size of 0.5, 1.0, 1.5 and 2.0 cm for early stage breast tumour detection. The tumours were inserted into the four common types of breast shape among women which were the tear drop, helical, round and triangular breasts. The fringe analysis conducted on the breast surface was based on the pixel coordinate and height map profile analysis which required the obtained fringe patterns to be phase mapped and phase unwrapped. The tear drop breast pixel coordinate with the presence of the 0.5 – 2.0 cm silicon catheter tumour has a shift of 4 - 13 pixels. The same silicon catheter tumour size variation was repeated for the helical, round and triangular shaped breasts and the pixel shifts obtained were 3 to 14, 4 to 12 and 3 to 15 respectively. The same tumour size of the silicon catheter tumour was also repeated with the metal screw tumour on all of the breast shapes. The pixel shift of the tear drop, helical, round and triangular breast obtained from the metal tumour was 7 to 24, 8 to 22, 7 to 21 and 7 to 21 respectively. All breast surfaces from the four types of breast shapes have shown a lower pixel coordinate shift with the presence of the silicon catheter tumour compared to the metal screw tumour. The height profile analysis also demonstrates an increase in height for all breast shapes for both silicon catheter and metal tumours when tumour size is increased. Both tumour size for silicon catheter and metal were also varied from 0.5 – 2.0 cm in the height map analysis. The height profile for all the breasts shows a maximum increase of height with the presence of 2.0 cm tumour for both silicon catheter and metal tumour. The maximum height increase when using silicon catheter tumours for the tear drop, helical, round and triangular breasts are 0.455, 0.270, 0.275 and 0.350 cm respectively. The maximum height increase when using metal tumours for the tear drop, helical, round and triangular breasts are 1.330, 0.895, 0.650 and 1.225 cm respectively. Simulation for the stress and strain of the breast surface based on glandular and fat tissue was also conducted using Salome and Elmer finite element method (FEM) to validate the results of breast surface changes obtained from the fringe projection system. The stress and strain assessment of the breast demonstrates that the breast experiences more stress with the increase of force and tumour size. The maximum stress of glandular tissue is during tumour size of 2 cm with a force of 5 N where the maximum stress is 4.51 Pa and 1.65 Pa for the glandular and fat breast tissue respectively. The highest strain also occurs during the maximum tumour size of 2 cm and force of 5 N which is 1.1 μm and 6.7 nm for the glandular and fat tissue respectively. The increase of stress and strain of the breast from the FEM simulations implies the presence of stress which causes the breast surface to experience surface changes thus being identified by the three step fringe projection. The three step digital fringe projection applied in this study has demonstrated its capability in identifying phantom breast surface changes in terms of pixel coordinate and maximum height changes caused by the presence of artificial silicon catheter tumours with their size progression.