ACKNOWLEDGEMENTS ..................................................................................... iii
LIST OF TABLES ................................................................................................... v
LIST OF FIGURES .................................................................................................. vi
CHAPTER
1. INTRODUCTION ........................................................................................ 1
An Introduction to Image Processing Techniques.............................. 3
Retinal Image Database......................................................................... 4
Placental Image D atabase.................................................................... 6
Preprocessing.......................................................................................... 7
2 . MULTISCALE VESSEL ENHANCEMENT......... ...................................... 14
Multiscale Differential Operators......................................................... 14
Vessel Extraction with the Hessian...................................................... 20
Results on Retinal Im ages.................................................................... 24
Limitations of Multiscale Vessel Enhancement.................................. 28
3. DIRECTIONAL FILTER BANK VESSEL ENHANCEMENT ............ 31
Decimation-Free Directional Filter Bank (D D FB).............................. 32
Constructing the Filters......................................................................... 34
Spatial and Frequency domain ............................................................. 37
Diamond F ilte r....................................................................................... 43
Constructing the Wedge F ilters........................................................... 45
DDFB-based Vessel Enhancement ...................................................... 49
Results on Retinal Im ages.................................................................... 52
Results on Placental Images................................................................. 65
4. CONCLUSION ............................................................................................... 77
APPENDIX: MATLAB CODES ............................................................................ 79
BIBLIOGRAPHY ..................................................................................................... 109
