Arquitectura eficiente para el procesamiento de un array ultrasónico basado en técnicas de codificación

En este trabajo se presenta una implementación basada en SoC (System on Chip), para un sistema de generación de imágenes de ultrasonidos en aire mediante el uso de macro-secuencias, derivadas de conjuntos de secuencias complementarias (CSS), con el fin de realizar la exploración de varios sectores simultáneamente. Mediante la concatenación de secuencias CSS interpoladas con ceros se obtienen macrosecuencias cuyas funciones de auto-correlación y correlación cruzada presentan una zona de correlación cero (ZCZ), la cual puede ser ajustada para lograr una ventana libre de interferencias en el área a analizar. Los resultados de correlación obtenidos a partir de los ecos de las macro-secuencias recibidas proporcionan las líneas A-scan de la imagen B-scan final. En comparación con otros esquemas de codificación, que también proporcionan ZCZ, esta solución permite reducir la carga computacional y por lo tanto el número de recursos hardware necesarios, lo que facilita un procesado en tiempo real. Se presenta la implementación hardware sobre una plataforma FPGA de Xilinx de los bloques de emisión y recepción del sistema de generación de imágenes de ultrasonidos, para un array US de 8 elementos y la exploración simultánea de hasta 32 sectores diferentes, con una profundidad de 1.5 m y una apertura de ±64º.This work presents a SoC-based implementation for ultrasonic imaging systems in airborne transmission which uses macro-sequences derived from complementary set of sequences (CSS) to achieve simultaneous beam steering in several directions. By means of CSS concatenation and zero padding a new macro-sequence can be obtained which achieves zero auto- and crosscorrelation zone (ZCZ) characteristics that can be adjusted to provide interference-free CDMA within the scanning area. The correlation results with the emitted macro-sequences provide the A-scan lines of the final B-scan image. In contrast to other encoding schemes with similar ZCZ size, the one proposed here allows a hardware design that further minimizes the computational load to make real-time processing more feasible. The hardware implementation in a Xilinx FPGA of all the stages forming the emission and reception modules of the imaging ultrasonic system is presented. The array has 8 elements and permits the simultaneous analysis of 32 different sectors, with a 1.5m depth and ±64°aperture.Máster Universitario en Sistemas Electrónicos Avanzados. Sistemas Inteligentes (M128

Ultrasonic distance scanning techniques for mobile robots

This paper discusses the application of ultrasound to mobile robot navigation. Two methods employing transducer arrays are described, namely the phased array (PA) method and the maximum-likelihood-estimation (MLE) method. These two methods are compared with the conventional time-of-flight (ToF) method. The paper shows that the PA method has advantages such as giving focused beams and allowing efficient beam steering. Limitations of the method are also discussed, including the need to assume a far-field, the undesired side grating lobes and the unavailability of suitably-sized transmitters. In order to understand the measurement uncertainty, a quantified estimation of the effective range and bearing measurement is calculated. The MLE method has the advantage of only involving one transmitter. The locations of the reflectors employed with this method can be represented in a probability map. Experimental results show that the reliability can be improved through the use of multiple receivers

Ultrasonic distance scanning techniques for mobile robots

This paper discusses the application of ultrasound to mobile robot navigation. Two methods employing transducer arrays are described, namely the phased array (PA) method and the maximum-likelihood-estimation (MLE) method. These two methods are compared with the conventional time-of-flight (ToF) method. The paper shows that the PA method has advantages such as giving focused beams and allowing efficient beam steering. Limitations of the method are also discussed, including the need to assume a far-field, the undesired side grating lobes and the unavailability of suitably-sized transmitters. In order to understand the measurement uncertainty, a quantified estimation of the effective range and bearing measurement is calculated. The MLE method has the advantage of only involving one transmitter. The locations of the reflectors employed with this method can be represented in a probability map. Experimental results show that the reliability can be improved through the use of multiple receivers