The Moving Picture Experts Group - 1 (MPEG-1) perceptual audio compression scheme is a successful family of audio codecs described in standard ISO/IEC 11172–3. Currently, there is no general framework to emulate nor MPEG-1 neither any other psychoacoustic model, which is a core piece of many perceptual codecs. This work presents a successful implementation of a convolutional neural network which emulates psychoacoustic model 1 from the MPEG-1 standard, termed “MCNN-PM” (Multiscale Convolutional Neural Network – Psychoacoustic Model). It is then implemented as part of the MPEG-1, Layer I codec. Using the objective difference grade (ODG) to evaluate audio quality, the MCNN-PM MPEG-1, Layer I codec outperforms the original MPEG-1, Layer I codec by up to 17% at 96 kbps, 14% at 128 kbps and performs almost equally at 192 kbps. This work shows that convolutional neural networks are a v...

This work proposes a computational algorithm which extracts the frequency, timings and signal segments corresponding to respiratory phases, through buccal and nasal acoustic signal processing. The proposal offers a computational solution for medical applications which require on-site or remote patient monitoring and evaluation of pulmonary pathologies, such as coronavirus disease 2019 (COVID-19). The state of the art presents a few respiratory evaluation proposals through buccal and nasal acoustic signals. Most proposals focus on respiratory signals acquired by a medical professional, using stethoscopes and electrodes located on the thorax. In this case the signal acquisition process is carried out through the use of a low cost and easy to use mask, which is equipped with strategically positioned and connected electret microphones, to maximize the proposed algorithm's performance. The al...

Se plantea un método de reconocimiento de marcas ópticas utilizando una cámara WEB a través del presente trabajo. El mismo se orienta al reconocimiento del código y la nota de un estudiante en un cuadernillo de evaluación. Las marcas se generan en el cuadernillo utilizando un lapicero. Se utilizan algoritmos y técnicas de procesamiento de imágenes como el filtrado espacial, umbralización, segmentación, descripción y reconocimiento a través de redes neuronales. El método propuesto permite automatizar el ingreso de notas académicas a una base de datos, sin alterar significativamente el formato de los cuadernillos utilizado en las evaluaciones de los estudiantes. Los resultados obtenidos demuestran que el método propuesto alcanza un error máximo del 2% en el proceso de reconocimiento.

Se plantea un método de reconocimiento de marcas ópticas utilizando una cámara WEB a través del presente trabajo. El mismo se orienta al reconocimiento del código y la nota de un estudiante en un cuadernillo de evaluación. Las marcas se generan en el cuadernillo utilizando un lapicero. Se utilizan algoritmos y técnicas de procesamiento de imágenes como el filtrado espacial, umbralización, segmentación, descripción y reconocimiento a través de redes neuronales. El método propuesto permite automatizar el ingreso de notas académicas a una base de datos, sin alterar significativamente el formato de los cuadernillos utilizado en las evaluaciones de los estudiantes. Los resultados obtenidos demuestran que el método propuesto alcanza un error máximo del 2% en el proceso de reconocimiento.

Cervical cancer is one of the main causes of death by disease worldwide. In Peru, it holds the first place in frequency and represents 8% of deaths caused by sickness. To detect the disease in the early stages, one of the most used screening tests is the cervix Papanicolaou test. Currently, digital images are increasingly being used to improve Pap test efficiency. This work develops an algorithm based on adaptive thresholds, which will be used in Pap smear assisted quality control software. The first stage of the method is a pre-processing step, in which noise and background removal is done. Next, a block is segmented for each one of the points selected as not background, and a local threshold per block is calculated to search for cell nuclei. If a nucleus is detected, an artifact rejection follows, where only cell nuclei and inflammatory cells are left for the doctors to interpret. The ...

This work proposes an electronic equipment aimed at measuring the color difference between fabrics for a homogeneous selection of these. The proposed method analyzes tissues with different illuminants so that, by taking measurements with a camera, the impact of effects such as metamerism can be reduced, resulting in a more accurate method that represents reality. For this, an enclosure was designed and built to allow constant lighting conditions and spotlights with standard lighting were installed. On the software side, the camera was manually configured to ensure persistent measurements over time and the colors obtained from the RGB color space were converted to CIELAB. For the calculation of the color difference, the Delta E (CMC) color difference equation was used because this is the standard used in the textile industry. Finally, a neural network was trained to estimate the color dif...

This work proposes an electronic equipment which identifies forest seeds for academic and research purposes. Existing integral solutions are prohibitively costly for silviculture laboratories used in forestry teaching. Thus, they must identify the seed by visual inspection, causing visual fatigue and results with low reliability. The state of the art proposes solutions using support vector machines, achieving a 98.82% accuracy for sunflower seeds. Other solutions extract morphological attributes of mussel seeds to identify up to 5 species with an accuracy of 95%. Most solutions only identify a single seed type with similar sizes. In this context, an electronic equipment is developed. It consists of an image acquisition enclosure, an electromechanical device to move a camera so different sizes of seeds can be imaged at different distances, and a single-board computer to control the image ...

Today, eavesdropping is becoming a common issue in the rapidly growing digital network and has foreseen the need for secret communication channels embedded in digital media. In this paper, a novel steganography technique designed for Standard Definition Digital Television (SDTV) H.264/AVC encoded video sequences is presented. The algorithm introduced here makes use of the compression properties of the Context Adaptive Variable Length Coding (CAVLC) entropy encoder to achieve a low complexity and real-time inserting method. The chosen scheme hides the private message directly in the H.264/AVC bit stream by modifying the AC frequency quantized residual luminance coefficients of intrapredicted I-frames. In order to avoid error propagation in adjacent blocks, an interlaced embedding strategy is applied. Likewise, the steganography technique proposed allows self-detection of the hidden messag...

This work proposes a computational algorithm to convert digital files containing electrocardiogram (ECG) information into 1D signals. Many medical databases have in storage files containing ECG information that is not easy to process for computational algorithms. Digitization by the proposed method makes it possible to modernize the databases of many health centers in order to perform post-processing of the signals obtained. This method is based on applying digital signal processing techniques to images obtained from a PDF file produced by an electrocardiograph. The proposed algorithm takes into consideration the thickness of the printed signal in the PDF image so that it does not introduce distortion in the final 1D signal. Due to the distribution of the ECG signals on the PDF files the algorithm identifies and segments the signals on 2 dimensions. The results show that the proposed met...

This work proposes a computational algorithm which monitors voice/audio signals demodulated from a FM receptor and detects whether they are intelligible or not. Data analytics applications which require the continuous storage of radio broadcasted audio signals into a database can benefit from this algorithm. In many instances, the broadcasted signals arrive at the receptor with heavy distortion and noise content, limiting the data analysis due to poor data quality. Moreover, radio spectrum supervisory agencies can also take advantage of this work, since broadcasted signals can be efficiently and continuously monitored to detect whether a broadcaster has stopped transmitting for an extended period. First, the algorithm processes the demodulated signals block by block, extracting its MFCC coefficients, spectral centroid, the arithmetic and geometric means of the frequency magnitude spectru...

Correctly executing exercises during training is of vital importance to ensure adequate athletic performance. Sit-ups are among the most frequently performed exercises requiring proper evaluation. This exercise contributes to increasing abdomen strength, having better posture to reduce back problems, and improving overall physical condition and appearance, among other benefits. Existing methods for evaluating the correct execution of sit-ups are manual, subjective, and inefficient in terms of time, cost, and precision. Therefore, there is a need to have technological tools that measure and monitor core abdominal strength while simultaneously verifying, through image processing, the correct execution of the exercise. Since no solutions with these capabilities have been found in the literature, this work proposes a system that performs these functions using electromyographic (EMG) sensors,...

This work proposes an electronic equipment which determines the marbling grade in beef rib eye according to the American grading scale using digital image processing and machine learning, achieving an 88.89 % coincidence level with grading done by beef specialists. Existing solutions which use image processing usually require calibration methods due to working in non-controlled environments. Furthermore, they only acquire the fat distribution from the longissimus dorsi muscle with an approximate accuracy of 80 %, without referring the distribution to any quality standard. In this work, meat samples are placed in a food grade stainless-steel enclosure with a touch screen and a digital RGB camera. The device acquires an image of the rib eye, which is then analyzed using techniques such as adaptive histogram analysis based on the HSV color model, histogram peaks detection for grayscale thre...

Long and monotonous journeys during the transport of goods can generate tiredness and/or fatigue in the driver, generating a potential vehicle accident where the driver can enter a state of micro-sleep, losing control of the vehicle for a period of time. Within the state of the art, it is observed that most of the solutions have as their fundamental axis the analysis of the ocular muscle, being these vulnerable to the variation of light intensity and facial accessories that the driver can use. On the other hand, other studies analyze EEG signals being intrusive and disturbing the driving skills of the driver. This work presents a driver fatigue monitoring system based on the angular movement of the head, the main characteristic prior to the state of micro-sleep, located in a safety helmet. To do this, an analysis of the angular movement of the driver’s head is carried out, thus avoidin...

This paper presents an analysis and design of moisture sensor for South American wood species. The proposed sensor is designed to non-invasively measure the estimated moisture content of a piece of wood based on its dielectric properties. The article provides the methodology for designing and developing an inter-digital capacitance sensor, along with its implementation using a multi-stage amplifier circuit.

This article outlines the analysis and characterization of a moisture sensor designed specifically for wood species, including uncommon ones not found in Europe and North America. The profiling of these varieties has been devised to gauge the moisture levels within a wooden specimen through the utilization of a non-intrusive capacitance sensor, deriving values from the inherent dielectric characteristics of the material. Diverse wood species underwent thorough characterization, and a proposed multiple regression model aims to facilitate the precise calibration of the sensor concerning South American timber varieties and other uncommon species not found in Europe and North America.

The present work proposes an encoder for image transmission via LoRa communication modules. These enable long-range, low-power transmission schemes and are ideal for monitoring in places with no mobile network connectivity. Nonetheless, this technology has a low transmission bitrate, which limits its use to high bandwidth applications. The state-of-the-art has numerous image encoders, but few achieve an adequate balance between image quality, compression, sequential decoding, and computational complexity. The proposed encoder uses the YCoCg color model and chromatic subsampling followed by wavelet subband decomposition, which extracts relevant subbands in the image to then reconstruct it sequentially. Each subband is quantized independently and then enters an adaptive entropic encoder. This encoder is compared to the JPEG2000 encoder using the peak signal-to-noise ratio (PSNR) and struct...

Article

Weather radar calibration is a crucial factor to be considered for quantitative applications, such as QPE (Quantitative Precipitation Estimation), which is used as input for weather risks management. The present work proposes a novel approach to the end-to-end radar calibration method through the characterization of the radar weighting functions. These are Gaussian functions that model an additional attenuation factor to the radar received power. This approach, based on the inclusion these parameters, allow the obtainment of a calibrated equivalent reflectivity factor expression for a Doppler dual-polarization weather radar that operates in the X band. To calculate these parameters, a UAS (Unmanned Aircraft System) was implemented for suspending the calibration target with a well-defined cross-section and for measuring its inclination due to wind using an IMU (Inertial Measurement Unit)....

Weather radar calibration is a crucial factor to be considered for quantitative applications, such as QPE (Quantitative Precipitation Estimation), which is used as input for weather risks management. The present work proposes a novel approach to the end-to-end radar calibration method through the characterization of the radar weighting functions. These are Gaussian functions that model an additional attenuation factor to the radar received power. This approach, based on the inclusion these parameters, allow the obtainment of a calibrated equivalent reflectivity factor expression for a Doppler dual-polarization weather radar that operates in the X band. To calculate these parameters, a UAS (Unmanned Aircraft System) was implemented for suspending the calibration target with a well-defined cross-section and for measuring its inclination due to wind using an IMU (Inertial Measurement Unit)....

Maximizing crop production efficiently and sustainably through plant health monitoring is key for global food security. Monitoring large areas with remote sensing technologies such as unmanned aerial vehicles (UAVs) with sensors deals with time and money issues; however, the usage of advanced sensors such as hyperspectral, multispectral and thermal cameras limit their usage among all the stakeholders. In this study we explore different vegetation indices (VIs) extracted from aerial RGB images acquired in different flights to differentiate the nutritional and water statuses of Hass avocado plantations. We used an image processing workflow consisting of image selection through a convolutional neural network (CNN) model, tree crown segmentation, color correction and feature extraction to automate the computation of VIs from RGB images. To compare the performance of VIs in the differentiatio...