Score extraction usign MPEG-4 T/F partial encoding

This paper describes the preliminary work in the development of an MPEG-4 audio transcoder between the time/frequency (T/F) and the structured audio (SA) formats. Our approach consists in not going from T/F format through to waveform data and back again to SA, but extracting the score information from an intermediate stage. For this intermediate form we have chosen the input of the filterbank and block switching tool, which consists of frequency data. This data is the result of windowing and applying the modified discrete cosine transform (MDCT) to the signal. The size of the window to be used is determined in a frame-by-frame basis by a psychoacoustics analysis of the data. In this paper we show that this approach is feasible by developing a system which extracts the score information from the filterbank and block switching tool output in a MPEG-4 T/F encoder by adapting and fine-tuning some existing processing techniques.Peer ReviewedPostprint (published version

An experimental course on digital communications

In this paper a laboratory course on digital communications is presented. This course has been designed for medium degree professionals in the telecommunications field, and it is based on training equipment developed to change the usual theoretical classrooms for laboratory seminars.Peer ReviewedPostprint (published version

New receivers for DS-SS in time variant multipath channels based on the PN alignment concept

We present new combined blind equalization and detection schemes for a DS-SS system. The new proposed algorithms improve the bit error rate compared to traditional RAKE receivers in time-variant channels with multipath. This improvement is obtained in both simulated and a real ionospheric HF link. Its very low computational complexity makes them suitable to be implemented in real receivers.Peer ReviewedPostprint (published version

DSP-based ionospheric radiolink using DS-CDMA and on-line channel estimation

In this paper, a new blind multiuser detection algorithm is presented. It can both cancel multiuser interference and estimate the multipath channel response in a blind way. The method has been specially conceived for low coherence bandwidth channels such as the ionospheric channel and exhibits very low computational requirements. Real-time measurements from a fully digital HF radio-link are presented that confirm the reliability of the method for the ionospheric channel.Peer ReviewedPostprint (published version

Combining computer vision and deep learning to classify varieties of Prunus dulcis for the nursery plant industry

Varietal control to avoid unwanted varietal mixtures is an important objective for the nursery plant industry. In this study, we have developed and analyzed the capabilities of a computer vision system based on deep learning for the control of plant varieties in the nursery plant industry and for evaluating its capabilities. For this purpose, three datasets of nursery plant images were compared. The datasets came from two varieties of almond trees (Prunus dulcis) named Soleta and Pentacebas. Each dataset contained images with three different scales: whole plant, leaf, and venation. The Gradient-weighted Class Activation Mapping (Grad-CAM) technique was used to unveil the most important features to discriminate between both varieties. The three datasets provided classification accuracies above 97% in the test set, being the leaf dataset, with a 98.8% accuracy, the one providing the best results. Concerning the most important features of the plants, the Grad-CAM showed that they are located in the center of the leaf, that is, the venation. In conclusion, we have shown that computer vision is a promising technique for the control of plant varietal mixtures.Spanish Ministry of Economy andCompetitiveness, Grant/Award Number:AGL2015-70106-R, AEI/FEDER, UE;Industrial Doctorates Plan of theSecretariat of Universities and Research ofthe Department of Economy andKnowledge of the Generalitat of Catalonia,Grant/Award Number: DI-COF 2017Peer ReviewedPostprint (published version

Sistemas audiovisuales

Conté: 1. Televisión analógica y digitalEl libro presenta una descripción detallada de los diferentes sistemas de televisión analógica y digital e incluye un análisis exhaustivo de numerosos aspectos tecnológicos e históricos, siempre desde una perspectiva sistemática y generalista dirigida tanto a estudiantes universitarios como a técnicos de grado superior. Tras una introducción a los sistemas de comunicación visual, en la que se analizan las distintas etapas de la conversión de una escena tridimensional real en una señal de televisión, se tratan conceptos tan variados como la percepción de imágenes en movimiento, la descomposición de la luz y los principios de colorimetría, los sistemas de representación de imágenes en tres dimensiones, las relaciones de aspecto y los formatos panorámicos en cine y televisión, el muestreo temporal de la escena o el ancho de banda de las señales de televisión, y se introducen los formatos de televisión analógicos y digitales. Los temas dedicados específicamente a la televisión analógica (sistemas de blanco y negro, generalidades de los dispositivos de representación de imágenes mediante tubos de rayos catódicos y sistemas de color compatibles NTSC y PAL) y a la televisión digital (principios de codificación para imágenes estacionarias, JPEG, e imágenes en movimiento, MPEG-1 y MPEG-2, definición de la naturaleza de la información en las tramas de bits que se transmiten en los sistemas de radiodifusión de señales de televisión en formato digital, DVB) pueden abordarse de forma independiente y son autocontenidos. La parte final del libro se dedica al análisis de los sistemas de formación de imágenes, sensores CCD, unidades y parámetros de iluminación y tipos de cámaras