Physics based image interpretation to aid the detection of early signs of retinopathiesEPSRC Grant GR/S09906/01
The teamAntonio Calcagni, Ela Claridge, Jon Gibson, Mark O'Dwyer, Felipe Orihuela Espina, Iain Styles
School of Computer Science, The Unversity of Birmingham and Department of Ophthalmology, Heartlands Hospital, Birmingham
|Macular Pigment||Retinal Haemoglobins||RPE melanin|
|Choroidal Melanin||Choroidal Haemoglobins|
A crucial advance has been the development of a method for the recovery of parameters (a "model inversion") characterising the ocular fundus without the need for image calibration. The method is derived from an analysis of the imaging process and is completely generic. It has been subsequently applied to other imaging problems .
We have developed a multispectral image acquisition system which can capture images from large areas of the ocular fundus at wavelengths ranging from 400nm to 1100nm. Multispectral image data sets have been collected for healthy young volunteers from a variety of ethnic backgrounds including Caucasians, African, Afro-Carribean and Mediterranean. All technically sound image sets are available for other researchers from the Web repository
By applying the inverse model to every point in a multi-spectral image set, we can compute the values of the model parameters which describe the fundus tissue at that point and construct parametric maps which show the variation of each parameter across the entire image. Figures below show RGB images and the corresponding parametric maps for the Macular Pigment and the Retinal Haemoglobins. The maps are consistent with the anatomy and physiology of the fundus.
|RGB image of a normal subject.||Parametric map of the Macular Pigment; note the elevated levels of the pigment in the foveal area.|
|RGB image of a normal subject.||Parametric map of the Retinal Haemoglobins (RHb); retinal vessels can be clearly seen; note the decreased levels of RHb in the foveal avascular zone.|
|RGB image of a patient with retinal haemorrhage.||Parametric map of the Retinal Haemoglobins. note the elevated levels of RHb in the foveal area where retinal haemorrhage was diagnosed.|
Calcagni A, Styles IB, Claridge E, Orihuela Espina F, Gibson JM (2005) Multispectral fundus analysis. European Association for Vision and Eye Research Meeting EVER'05, Vilamoura, Portugal, October 2005. Abstract in Ophthalmic Research 37 (S1), 72. Abstracts.pdf and Poster (pdf.gz)
Preece S, Styles I, Cotton S, Claridge E, Calcagni A (2005) Model- based parameter recovery from uncalibrated optical images. Medical Image Computing and Computer Assisted Intervention (MICCAI 2005) Palm Springs, California, October 2005. LNCS vol. 3750, 509-516. Conference paper (pdf)
Styles IB, Claridge E, Orihuela Espina F, Calcalgni A, Gibson JM (2005) Quantitative interpretation of multispectral fundus images. Medical Imaging 2005: Physiology, Function, and Structure from Medical Images, Proceedings of SPIE Vol. 5746. Amini AA, Armando Manduca A Eds. (SPIE, Bellingham, WA, 2005), 267-278. Conference paper (pdf)
Orihuela Espina F (2005) Modelling and Verification of the Diffuse Reflectance of the Ocular Fundus. PhD Thesis. School of Computer Science, The University of Birmingham.
O'Dwyer M, Claridge E (2004) Single parameter recovery from modelled spectra: A comparison of spectral filter optimisation with standard multivariate approaches. Technical Report CSR-04-10, School of Computer Science, The University of Birmingham. (to be submitted to Pattern Recognition) CS-04-10.pdf
Preece SJ, Claridge E (2004) Physics-based approach to geometry insensitive recovery of quantitative scene parameters from images. Technical Report CSR-04-08, School of Computer Science, The University of Birmingham. CS-04-08.pdf
Orihuela-Espina, Claridge E, F Styles IB (2004) Validation of a physics based model of the reflectance of the ocular fundus. ARVO, Florida, April 2004. Abstract in Investigative Ophthalmology and Visual Science 2004, 45: E-Abstract 2789. Abstract and Poster.ppt
Styles IB, Claridge E, Orihuela-Espina F (2004) Quantitative interpretation of uncalibrated fundal images. ARVO, Florida, April 2004. Abstract in Investigative Ophthalmology and Visual Science 2004, 45: E-Abstract 2792. Abstract and Poster.pdf
Orihuela F, Claridge E (2003) A new optical imaging method for the ocular fundus. Medical Imaging Research Symposium, San Diego, August 2003. Abstract in Medical Physics 30(6), 1540.
Orihuela-Espina F, Claridge E, Preece SJ (2003) Histological parametric maps of the human ocular fundus: preliminary results. Medical Image Understanding and Analysis 2003, 133-136. Conference paper (pdf)
Preece SJ, Claridge E (2004) Spectral filter optimisation for the recovery of parameters which describe human skin. IEEE Pattern Analysis and Machine Intelligence, 26(7), 913-922. pdf
Claridge E, Preece SJ (2003) An inverse method for the recovery of tissue parameters from colour images. Information Processing in Medical Imaging (IPMI), Taylor C and Noble JA (Eds.) LNCS 2732, 306-317. Springer. pdf
Wrage H (2002) Under the skin. Professional Engineering 15(23A): Medical Engineering Supplement, December 2002, S6-S7.
O'Dwyer M, Claridge E, Ponman T, Raychaudhury S. (2005) Mapping the physical properties of cosmic hot gas with hyper-spectral imaging. IEEE Workshop on Applications of Computer Vision, Colorado, January 2005, 185-190. pdf
Temple R, Claridge E, O'Dwyer M, Ponman T, Raychaudhury S (2005) Mapping the physical properties of cosmic hot gas with hyper- spectral imaging. Royal Astronomical Society National Astronomy Meeting 2005, Birmingham, UK. (abstract)
Hidovic D, Claridge E (2005) Modelling and validation of spectral reflectance for the colon. Physics in Medicine and Biology 50, 1071- 1093. pdf