Abstract: This paper discusses a corner detection algorithm
for camera calibration. Calibration is a necessary step in many
computer vision and image processing applications. Robust
corner detection for an image of a checkerboard is required
to determine intrinsic and extrinsic parameters. In this paper,
an algorithm for fully automatic and robust X-corner detection
is presented. Checkerboard corner points are automatically
found in each image without user interaction or any prior
information regarding the number of rows or columns. The
approach represents each X-corner with a quadratic fitting
function. Using the fact that the X-corners are saddle points,
the coefficients in the fitting function are used to identify each
corner location. The automation of this process greatly simplifies
calibration. Our method is robust against noise and different
camera orientations. Experimental analysis shows the accuracy
of our method using actual images acquired at different camera
locations and orientations.
Abstract: CRLH (composite right/left-handed) based and SRR (split-ring resonator) based filters have been designed at microwave frequency which can provide better performance compared to conventional edge-coupled band-pass filter designed around the same frequency, 2.45 GHz. Both CRLH and SRR are unit cells used in metamaterial design. The primary aim of designing filters with such structures is to realize size reduction and also to realize novel filter performance. The CRLH based filter has been designed in microstrip transmission line, while the SRR based filter is designed with SRR loading in waveguide. The CRLH based filter designed at 2.45 GHz provides an insertion loss of 1.6 dB with harmonic suppression up to 10 GHz with 67 % size reduction when compared with a conventional edge-coupled band-pass filter designed around the same frequency. One dimensional (1-D) SRR matrix loaded in a waveguide shows the possibility of realizing a stop-band with sharp skirts in the pass-band while a stop-band in the pass-band of normal rectangular waveguide with tailoring of the dimensions of SRR unit cells. Such filters are expected to be very useful for communication systems at microwave frequency.