Usage of high resolution and high frame rate cameras in multi-sensor imaging systems has led to increased need for high computational power demanding video signal processing. One very strict requirement is to minimize payload weight on pan-tilt platforms (PT), that prevents installation of high power computers on rotation part of PT. Instead, raw video signal from multiple cameras should be transmitted via PT slip ring to the processing board which is installed as a stationary equipment. The required capacity of this communication link can easily reach values of multiple Gbps which would yield to use of very expensive slip rings with strictly impedance controlled copper contacts or even fiber optics. Additionally, the lifetime of such slip ring is much shorted than low capacity slip rings. In this paper we propose the solution that uses slip ring central opening as a circular waveguide for radio transmission of video signal. This concept originates from radars' rotary joints circuitry which additionally should transmit wideband signal. The main focus is in this paper is on simple and cost effective implementation based on FPGA serializer and deserializer as signal processing components. The coupling between FPGA and circular waveguide is provided by passive circuits and amplifiers. We have chosen coding and modulation suitable for this implementation that enables efficient digital video signal transmission over circular-waveguide based slip ring with bandpass characteristic. We have presented measurement results of 3Gbps transmission system that uses waveguide designed for cut off frequency of 10.7 GHz. The remarks about scaling this solution to different central frequencies and different bandwidths are given.
A calibration platform for geometric calibration of multi-sensor image fusion system is presented in this paper. The
accurate geometric calibration of the extrinsic geometric parameters of cameras that uses planar calibration pattern is
applied. For calibration procedure specific software is made. Patterns used in geometric calibration are prepared with
aim to obtain maximum contrast in both visible and infrared spectral range - using chessboards which fields are made of
different emissivity materials. Experiments were held in both indoor and outdoor scenarios. Important results of
geometric calibration for multi-sensor image fusion system are extrinsic parameters in form of homography matrices
used for homography transformation of the object plane to the image plane. For each camera a corresponding
homography matrix is calculated. These matrices can be used for image registration of images from thermal and low
light camera. We implemented such image registration algorithm to confirm accuracy of geometric calibration procedure
in multi-sensor image fusion system. Results are given for selected patterns - chessboard with fields made of different
emissivity materials. For the final image registration algorithm in surveillance system for object tracking we have chosen
multi-resolution image registration algorithm which naturally combines with a pyramidal fusion scheme. The image
pyramids which are generated at each time step of image registration algorithm may be reused at the fusion stage so that
overall number of calculations that must be performed is greatly reduced.