Apurba Sarkar

Finding a largest rectangle inside a digital object and rectangularization

Abstract A combinatorial algorithm to find a largest rectangle (LR) inside the inner isothetic cover which tightly inscribes a given digital object without holes is presented here which runs in O ( k . n / g + ( n / g ) log ⁡ ( n / g ) ) time, where n , g , and k being the number of pixels on the contour of the digital object, grid size, and the number of convex regions, respectively. Certain combinatorial rules are formulated to obtain an LR. An LR divides the object in several parts. The object can be rectangularized by recursive generation of a set of LRs and it generates LR-Graph which is useful for shape analysis.

Finding Shortest Triangular Path in a Digital Object

A combinatorial algorithm to find a shortest triangular path STP between two points inside a digital object imposed on triangular grid is designed having

Generation of Random Digital Curves Using Combinatorial Techniques

O\frac{n}{g} \log \frac{n}{g}

Rough K-Means and Morphological Operation-Based Brain Tumor Extraction

time complexity, n being the number of pixels on the contour of the object and g being the grid size. First the inner triangular cover of the given digital object is constructed which maximally inscribes the object. Certain combinatorial rules are formulated based on the properties of triangular grid and are applied whenever necessary to obtain a shortest triangular path, where the path lies entirely in the digital object and moves only along the grid edges. The length of STP and number of monotonicity may be two useful parameters to determine shape complexity of the object. Experimental results show the effectiveness of the algorithm.

A Dynamic Spatial Fuzzy C-Means Clustering-Based Medical Image Segmentation

We present a combinatorial algorithm which runs in

Adaptive Histogram Equalization and Opening Operation-Based Blood Vessel Extraction

On \log n