Rapid advancements in EO/IR imaging technology boosted by developments in focal plane array technology led to significant increase in performance, availability and accordingly in application in the various systems. As a consequence the more efforts in the area of possible countermeasure development are necessary. Starting from EO/IR generalized image forming process and related influences on the imager performances as key part of imager performance, using knowledge generated from well-established electronic countermeasure science and known results in EO/IR countermeasure application, EO/IR countermeasures classification is proposed. Using this classification the currently known countermeasures are analyzed trying to identify existing challenges for future efforts. Also the recent advanced in image processing techniques, i.e. application of artificial intelligence for automatic target recognition, could be used as EO/IR imaging counter-counter measure and should be considered separately.
The influence of the water on the scene IR signature is analyzed. The atmospherical water influence i.e. influence of the atmospheric meteorological conditions and humidity, are well known and described throughout the literature. However the research of water film influence on the IR signature is less covered in the. In this article we analyzed the influence of the water film on the scene signature. This analysis consists of the simplified theoretical model definition, followed by qualitative experimental research results, and compared with selected published results. The structure of the experimental IR scenes is described. The main sources that contribute to the scene IR signature are identified – differences in emissivity and differences in temperature, and they are reproduced in the experimental scene. In the experimental investigations the two scene types were used: (a) scene elements are in thermal equilibrium, but thermal image generation is based on the differences in emissivity; (b) scene consists of uniform background and several pieces of the some type object with different temperature. Thin water film is applied on both scenes. The experimental results are presented and explained. Experimental results show that water film significantly influences to the appearance of the thermal image generated based on emissivity differences. In the case of the temperature differences in the scene, the effect of the water film influences to the generated thermal image is visible only during the process of the water film generation. The influence depends on the quantity of water. The experimental results qualitatively prove the correctness of the starting hypothesis also as results of the theoretical model evaluation.
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.