Source identification for mobile devices, based on wavelet transforms combined with sensor imperfections

One of the most relevant applications of digital image forensics is to accurately identify the device used for taking a given set of images, a problem called source identification. This paper studies recent developments in the field and proposes the mixture of two techniques (Sensor Imperfections and Wavelet Transforms) to get better source identification of images generated with mobile devices. Our results show that Sensor Imperfections and Wavelet Transforms can jointly serve as good forensic features to help trace the source camera of images produced by mobile phones. Furthermore, the model proposed here can also determine with high precision both the brand and model of the device

Identificación de la fuente en vídeos de dispositivos móviles

La realización de vídeos con dispositivos móviles se ha convertido en una actividad común dado su alto grado de utilización y el gran número de usuarios. Además, la portabilidad de este tipo de dispositivos hace que estén a mano de los usuarios gran cantidad de tiempo facilitando que se utilicen para generar vídeos en una gran diversidad de situaciones. Por tanto, estos vídeos pueden ser utilizados como evidencias en procesos judiciales. Todo lo anterior hace necesario contar con técnicas de análisis forense enfocadas en vídeos de dispositivos móviles dada las características peculiares de sus cámaras. En este trabajo se estudia la identificación de la fuente de adquisición de los vídeos de dispositivos móviles y se presenta una técnica basada en la extracción del ruido del sensor y la transformada wavelet de los fotogramas extraídos del vídeo. Estos fotogramas son extraídos mediante un algoritmo que tiene en cuenta la naturaleza de los mismos, mejorando la selección de los fotogramas a analizar. Finalmente se presentan experimentos con vídeos de dispositivos móviles para evaluar la validez de las técnicas utilizadas

Técnica digital para la medición óptica de distancia

Se describe un método de medición de distancia basado en el procesamiento de las imágenes digitales provenientes de una cámara fotográfica. Es una versión mejorada de la técnica de estadimetría. El método propuesto efectúa la medición a partir de una dimensión de referencia conocida, que se configura al comienzo de la medición. La imagen a procesar se transfiere a una PC por medio de una interfase USB o tarjeta de memoria. A partir de la identificación del objeto de referencia sobre la imagen, el algoritmo calcula automáticamente la distancia al mismo. Comparado al método tradicional, este presenta las siguientes ventajas: mejor resolución, facilidad de uso, no requiere regla graduada, cualquier objeto de dimensiones conocidas sirve como referencia, permite un registro automático de una secuencia de mediciones y pueden efectuarse mediciones en movimiento.Sociedad Argentina de Informática e Investigación Operativ

Information system for image classification based on frequency curve proximity

With the size digital collections are currently reaching, retrieving the best match of a document from large collections by comparing hundreds of tags is a task that involves considerable algorithm complexity, even more so if the number of tags in the collection is not fixed. For these cases, similarity search appears to be the best retrieval method, but there is a lack of techniques suited for these conditions. This work presents a combination of machine learning algorithms put together to find the most similar object of a given one in a set of pre-processed objects based only on their metadata tags. The algorithm represents objects as character frequency curves and is capable of finding relationships between objects without an apparent association. It can also be parallelized using MapReduce strategies to perform the search. This method can be applied to a wide variety of documents with metadata tags. The case-study used in this work to demonstrate the similarity search technique is that of a collection of image objects in JavaScript Object Notation (JSON) containing metadata tags.This work has been done in the context of the project “ASASEC (Advisory System Against Sexual Exploitation of Children)” (HOME/2010/ISEC/AG/043) supported by the European Union with the program “Prevention and fight against crime”.info:eu-repo/semantics/publishedVersio

Development of a micro-extruder with vibration mode for microencapsulation of human keratinocytes in calcium alginate

Microencapsulation is a promising technique to form microtissues. The existing cell microencapsulation technologies that involved extrusion and vibration are designed with complex systems and required the use of high energy. A micro-extruder with an inclusion of simple vibrator that has the commercial value for creating a 3D cell model has been developed in this work. This system encapsulates human keratinocytes (HaCaT) in calcium alginate and the size of the microcapsules is controllable in the range of 500-800 µm by varying the flow rates of the extruded solution and frequency of the vibrator motor ( I 0-63 Hz). At 0.13 ml/min of flow rate and vibration rate of 26.4 Hz, approximately 40 ± IO pieces of the alginate microcapsules in a size 632.14 ± I 0.35 µm were produced. Approximately I 00 µm suspension of cells at different cells densities of 1.55 x I 05 cells/ml and 1.37 x I 07 cells/ml were encapsulated for investigation of microtissues formation. Fourier transform infrared spectroscopy (FTIR) analysis showed the different functional groups and chemistry contents of the calcium alginate with and without the inclusion of HaCaT cells in comparison to the monolayers of HaCaT cells. From Field Emission Scanning Electron Microscope (FESEM) imaging, calcium alginate microcapsules were characterised by spherical shape and homogenous surface morphology. Via the nuclei staining, the distance between cells was found reduced as the incubation period increased. This indicated that the cells merged into microtissues with good cell-cell adhesions. After 15 days of culture, the cells were still viable as indicated by the fluorescence green expression of calcein­acetoxymethyl. Replating experiment indicated that the cells from the microtissues were able to migrate and has the tendency to form monolayer of cells on the culture flask. The system was successfully developed and applied to encapsulate cells to produce 3D microtissues

Development of a micro-extruder with vibration mode for microencapsulation of human keratinocytes in calcium alginate

Microencapsulation is a promising technique to form microtissues. The existing cell microencapsulation technologies that involved extrusion and vibration are designed with complex systems and required the use of high energy. A micro-extruder with an inclusion of simple vibrator that has the commercial value for creating a 3D cell model has been developed in this work. This system encapsulates human keratinocytes (HaCaT) in calcium alginate and the size of the microcapsules is controllable in the range of 500-800 µm by varying the flow rates of the extruded solution and frequency of the vibrator motor ( I 0-63 Hz). At 0.13 ml/min of flow rate and vibration rate of 26.4 Hz, approximately 40 ± IO pieces of the alginate microcapsules in a size 632.14 ± I 0.35 µm were produced. Approximately I 00 µm suspension of cells at different cells densities of 1.55 x I 05 cells/ml and 1.37 x I 07 cells/ml were encapsulated for investigation of microtissues formation. Fourier transform infrared spectroscopy (FTIR) analysis showed the different functional groups and chemistry contents of the calcium alginate with and without the inclusion of HaCaT cells in comparison to the monolayers of HaCaT cells. From Field Emission Scanning Electron Microscope (FESEM) imaging, calcium alginate microcapsules were characterised by spherical shape and homogenous surface morphology. Via the nuclei staining, the distance between cells was found reduced as the incubation period increased. This indicated that the cells merged into microtissues with good cell-cell adhesions. After 15 days of culture, the cells were still viable as indicated by the fluorescence green expression of calcein­acetoxymethyl. Replating experiment indicated that the cells from the microtissues were able to migrate and has the tendency to form monolayer of cells on the culture flask. The system was successfully developed and applied to encapsulate cells to produce 3D microtissues

Using crowdsourced web content for informing water systems operations in snow-dominated catchments

Snow is a key component of the hydrologic cycle in many regions of the world. Despite recent advances in environmental monitoring that are making a wide range of data available, continuous snow monitoring systems that can collect data at high spatial and temporal resolution are not well established yet, especially in inaccessible high-latitude or mountainous regions. The unprecedented availability of user-generated data on the web is opening new opportunities for enhancing real-time monitoring and modeling of environmental systems based on data that are public, low-cost, and spatiotemporally dense. In this paper, we contribute a novel crowdsourcing procedure for extracting snow-related information from public web images, either produced by users or generated by touristic webcams. A fully automated process fetches mountain images from multiple sources, identifies the peaks present therein, and estimates virtual snow indexes representing a proxy of the snow-covered area. Our procedure has the potential for complementing traditional snow-related information, minimizing costs and efforts for obtaining the virtual snow indexes and, at the same time, maximizing the portability of the procedure to several locations where such public images are available. The operational value of the obtained virtual snow indexes is assessed for a real-world water-management problem, the regulation of Lake Como, where we use these indexes for informing the daily operations of the lake. Numerical results show that such information is effective in extending the anticipation capacity of the lake operations, ultimately improving the system performance

Introduction to the International Journal of Spatial Data Infrastructures Research

This paper introduces the new International Journal of Spatial Data Infrastructures Research and set out its rationale and aims. The paper is organized into four main sections discussing the recent development of Spatial Data Infrastructures (SDI), the reasons justifying a specific research effort on SDIs, the areas of research that are currently central to their further development and use, and their relationships with research in the field of GI Science. An overview of the current research effort at the Joint Research Centre in this field is also presented

An Experimental investigation of presentation medium–dependent differences of picture consumption by college-aged adults

While digital camera owners are taking more photos than ever before, most of them are not printing the photos. When they do, they only print in small quantities. The reason for this is that most users share their photos online or through e-mail. While fewer people print their images at the moment they are taking them, they are saving the digital files of the photos for future use. In conducting a literature review, a good overview was acquired of the current consumer photographer\u27s practices in taking, sharing, and saving pictures. In addition, a first experiment was set up involving college-aged young adults as the population. This first experiment focused on presentation medium-dependent differences in picture consumption, as well as consumer printing behavior regarding their own photographs. A following experiment took a second look at presentation medium-dependent differences in picture consumption. In addition, it provided a more complete picture of sharing and saving behavior, as well as an understanding of the value that observers place on conventional photographic images. The outcome of these experiments showed that most participants preferred printed images over on-screen images. Regardless of this finding, participants did not print images very often for a variety of reasons, including lack of time or money. In addition, results showed that the most commonly used printing tools included Kodak Gallery EasyShare, Shutterfly, and Flickr. Finally, participants cited Photoshop, Lightroom, and Picasa as the primary editing tools, with Facebook being mentioned as the main sharing tool