  Frangi Filters are one of the widely used filters for enhancing vessels in
medical images. Since they were first proposed, the threshold of the vesselness
function of Frangi Filters is to be arranged for each individual application.
These thresholds are changed manually for individual fluoroscope, for enhancing
coronary angiogram images. Hence it is felt, there is a need of mitigating the
tuning procedure of threshold values for every fluoroscope. The current papers
approach has been devised in order to treat the coronary angiogram images
uniformly, irrespective of the fluoroscopes through which they were obtained
and the patient demographics for further stenosis detection. This problem to
the best of our knowledge has not been addressed yet. In the approach, before
feeding the image to Frangi Filters, non uniform illumination of the input
image is removed using homomorphic filters and the image is enhanced using Non
Subsampled Contourlet Transform (NSCT). The experiment was conducted on the
data that has been accumulated from various hospitals in India and the results
obtained verifies dependency removal of parameters without compromising the
results obtained by Frangi filters.
