Design of a vision-based traffic analytic system for urban traffic video scenes has a great potential in context of Intelligent Transportation System (ITS). It offers useful traffic-related insights at much lower costs compared to their conventional sensor based counterparts. However, it remains a challenging problem till today due to the complexity factors such as camera hardware constraints, camera movement, object occlusion, object speed, object resolution, traffic flow density, and lighting conditions etc. ITS has many applications including and not just limited to Queue estimation, Speed detection and different anomalies detection etc. All of these applications are primarily dependent on sensing vehicle presence to form some basis for analysis. Moving Cast shadows of vehicles is one of the major problems that affects the vehicle detection as it can cause detection and tracking inaccuracies. Therefore, it is exceedingly important to distinguish dynamic objects from their moving cast shadows for accurate vehicle detection and recognition. This paper provides an in-depth comparative analysis of different traffic paradigm-focused conventional and state-of-the-art shadow detection and removal algorithms. Till date, there has been only one brief survey which highlights the shadow removal methodologies particularly for traffic paradigm. In this paper, a number of research papers containing results of urban traffic scenes have been shortlisted from the last three decades to give a comprehensive overview of the work done in this area. The study reveals that the only way to make a comparative evaluation is to use the existing Highway I, II, and III datasets which are frequently used for qualitative or quantitative analysis of shadow detection or removal algorithms. Furthermore, the paper not only provides cues to solve moving cast shadow problems, but also suggests that even after the advent of Convolutional Neural Network (CNN)-based vehicle detection methods, the problems caused by moving cast shadows persists. Therefore, this paper proposes a hybrid approach which uses a combination of conventional and state-of-the-art techniques as a pre-processing step for shadow detection and removal before using CNN for vehicles detection. The results indicate a significant improvement in vehicle detection accuracies after using the proposed approach.

An improved version of a printed RHCP Archimedean spiral antenna for glacial environmental sensor networks is presented. Two changes have been made to the previous design. Firstly, the microstrip connections between the balun and the antenna arms have been tapered. Secondly, the antenna arms have been rounded at the edges towards the antenna boundary. These measures have improved the antenna performance in the following ways. Firstly, the signal quality has been improved by minimizing reflections and signal distortion. Secondly, the microstrip tapering between the balun and the antenna arms has increased the radiating surface area in the region. Resultantly, significant improvements in the antenna's reflection coefficient, gain, total efficiency, and axial ratio have been observed.

A left hand circularly polarized antenna called SPD-PCD (Symmetric phase difference -printed cross dipole) has been designed, developed, and experimentally validated for use with glacier telemetry surface receivers. The antenna is portable and easy to fabricate. It provides a gain of 5.9 dBic at 433 MHz, a 57 % -10 dB fractional bandwidth, and a -3 dB angular width of 60º in the vertical planes. The antenna offers good circular polarization with the axial ratio remaining below 1.1 dB between 330-580 MHz. The co-polarization is at least 10 dB stronger than cross-polarization within a beam width of 80º in both the vertical planes. This work also validates the 433 MHz band is suitable to achieve communication ranges of up to 2300 m through ice.

Suitability of a RHCP printed Archimedean spiral antenna for glacier telemetry applications in the 433 MHz band has been assessed for the first time. The developed antenna provides a gain of 7.4 dBic at 433 MHz and a -10 dB fractional bandwidth of 47% in snow. The antenna beamwidths in the vertical planes cater for misalignments between the transmitter and receiver antennas due to basal sliding. The measured axial ratio remained below 1.4 dB between 330-580 MHz. Lastly, evidence has been provided towards suitability of the 433 MHz band for achieving communication ranges up to 2300 metres in ice.

Antennas used in glacial environmental sensor networks and reported in the last two decades have been reviewed. A link budget framework for designing such antenna systems is presented and used to design an antenna system for deployment at the Thwaites glacier, Antarctica. Design details of two left hand circularly polarized cross dipole antennas, one for englacial sensor probes and the other for supraglacial surface receivers are presented. The probe antenna is a 3D bent cross dipole that fits within a borehole of 8 cm diameter while providing a 1 dBic gain at 433 MHz in ice. The surface receiver antenna is a planar printed antenna providing a gain of 6.1 dBic with a quarter wave reflector. Both antennas provide 3 dB beamwidths of at least 50 • in the xz and yz vertical planes catering for transmitter-receiver antenna misalignments caused by extended deployments. The antennas displayed good circular polarization and polarization purity traits. The 3 dB axial ratio bandwidths of both the antennas remained 54.9 %. The total efficiencies of the bent cross dipole and the surface receiver antennas were noted as 69.7 % and 86.9 % respectively. Lastly, the 433 MHz band has been validated for achieving englacial communication ranges of up to 2300 metres.INDEX TERMS Englacial sensor probe, link budget framework, cross dipole, glacier monitoring, bent cross dipole, planar printed antenna, 433 MHz frequency, communication through ice, Thwaites project.