Sami Khorbotly

A modified approximation of 2D Gaussian smoothing filters for fixed-point platforms

Gaussian smoothing filters are commonly used in various image processing applications to reduce the noise level in an image. The filters are particularly popular in edge detection algorithms because of their ability to smooth false edges and improve the edge detection performance. When implemented on a fixed-point computational platform, the filter coefficients are rounded and the implemented filter becomes a rounded approximation of the original one. In those implementations, system designers must balance between signal integrity and the hardware size they can afford in a particular design. In this work, we suggest a new “modified” method to approximate the coefficients of a 2D Gaussian filter. When implemented on a Field Programmable Gate Array (FPGA), the modified approximation filter is shown to generally deliver higher signal quality than its traditional “rounded” counterpart without any increase in the required resources.

Teachless teach-repeat: Toward vision-based programming of industrial robots

Modern programming of industrial robots is often based on the teach-repeat paradigm: a human operator places the robot in many key positions, for teaching its task. Then the robot can repeat a path defined by these key positions. This paper proposes a vision-based approach for the automation of the teach stage. The approach relies on a constant auto-calibration of the system. Therefore, the only requirement is a precise geometrical description of the part to process. The realism of the approach is demonstrated through the emulation of a glue application process with an industrial robot. Results in terms of precision are very promising.

Engineering student-design competition teams: Capstone or extracurricular?

Year after year, engineering student-design competitions continue to attract increasing attention from engineering programs across the country. The participation in these competitions is beneficial to both students trying to develop their design and networking abilities, and institutions trying to promote their programs and increase their visibility. Traditionally, the perception has been that the easiest, most straight forward way to participate in a student-design competition is to assign the competition project as a capstone senior design project. This way, a group of seniors work under the supervision of a faculty member to complete the project seeing that the completion is a graduation requirement. The recently emerging alternative is to form an extracurricular team of students whose goal is to exclusively participate in the competition. The extracurricular teams are mostly populated by sophomore and junior level students and driven only by their passion and self motivation rather than a curricular requirement. In this paper, we share our observation and experience to contrast both options and provide some recommendations.

Recursive implementation of exponential linear phase FIR filters

A family of exponential linear phase FIR filters that can be recursively implemented is proposed in this work. The advantage of this family is that the hardware implementation requires a fixed number of scalar multiplication and addition/subtraction operations, regardless of the filter order. Part of the arithmetic operations used in the implementation of these filters mandates exact computations, without any truncation or rounding. The paper includes a detailed discussion of the bit-width requirements of these operations. The proposed implementation is described in hardware description language and simulated using ModelSim. The simulation results show that, when done properly, the recursive implementation successfully achieved a linear phase response.

A Signal Distribution Network for Sequential Quantum-Dot Cellular Automata Systems

The authors describe a signal distribution network for sequential systems constructed using the Quantum-dot cellular automata (QCA) computing paradigm. This network promises to enable the construction of arbitrarily complex QCA sequential systems in which all wire crossings are performed using nearest neighbor interactions, which will improve the thermal behavior of QCA systems as well as their resistance to stray charge and fabrication imperfections. The new sequential signal distribution network is demonstrated by the complete design and simulation of a two-bit counter, a three-bit counter, and a pattern detection circuit.

Recursive implementation of gaussian filters with switching and reset hardware

This paper suggests the use of linear programming and curve fitting to approximate Gaussian filters with a combination of recursive linear-phase exponential filters. The switching and reset method is used to create a stable implementation of an otherwise unstable pole-zero cancelation in the exponential filters. The results show that an accurate approximation of a Gaussian filter, of any order, can be recursively implemented using only 18 constant coefficient multipliers and 26 adders.

A methodology for implementing pipelined fixed-point infinite impulse response filters

This paper outlines a methodology for implementing pipelined IIR digital filters that considers both how much pipelining to use and what fixed-point precisions are required. The methodology is applied to an example second-order IIR filter implemented on a field programmable gate array; the results show that the methodology allows exploration of the trade-offs between hardware size and throughput while ensuring that the implemented filters deliver a consistent quality of output.

A modified ant colony optimization algorithm for implementation on multi-core robots

The Ant Colony Optimization (ACO) algorithm is an evolutionary algorithm that bio-mimics the behavior of ants in finding the shortest path between an origin and a destination within a set of pre-determined constraints. The goal of this work is to create a small-scale application of the ACO using a swarm of small autonomous robots. We investigate the practical applicability of the algorithm in real-life situations by addressing the issues and challenges encountered in the transition from the modeling/simulation level to the real-life application of the algorithm. We also suggest some modifications that will make feasible the implementation of the algorithm on the robots limited computing systems. The results show that the suggested modified algorithm, when implemented on the robotic swarm, enables them to successfully identify the shortest path between two points. These results open the door to a wide variety of applications like search & rescue, path planning, and mass transportation.

A camera-based target tracking system for football playing robots

This paper describes the design and the implementation of an application-driven target tracking system. The objective of the system is to improve the performance of a team of football playing robots in a “modified rules” football game. In this application, a throwing robot, the “quarterback”, equipped with a camera will attempt to locate a flashing LED mounted on the target robot, the “wide receiver”. Once located, the quarterback will adjust its throwing speed and throwing angle to increase the chances to hit the wide receiver. The results show that, the quarterback had a 100% success rate in locating the receiver when the distance between the two is no more than 15 feet. The location of the target is estimated with an average error of less than 0.31 inch.

A modified SRF-PLL for phase and frequency measurement of single-phase systems

In this work, a single phase phase-locked-loop (PLL) that uses a low-pass notch filter is proposed. The new PLL was derived from the synchronous reference frame PLL (SRF-PLL) in which the dq axis components were generated using the αβ reference signals. The single-phase grid voltage was used as the α component, whereas the αβ component was derived by delaying the grid voltage by 90° in phase. The dynamics of the proposed PLL were compared to those of the SRF-PLL. The frequency measurement using the new PLL showed better performance over the SRF-PLL and a second-order generalized integrator (SOGI) PLL. The proposed PLL displayed better performance under both variable frequency and distorted grid voltage conditions. Experimental results were used to validate the dynamics obtained from the simulation results. The proposed method adds very little complexity to the conventional SRF-PLL.