3 resultados para Histograms

em Universidade Federal do Rio Grande do Norte(UFRN)


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Image segmentation is the process of labeling pixels on di erent objects, an important step in many image processing systems. This work proposes a clustering method for the segmentation of color digital images with textural features. This is done by reducing the dimensionality of histograms of color images and using the Skew Divergence to calculate the fuzzy a nity functions. This approach is appropriate for segmenting images that have colorful textural features such as geological, dermoscopic and other natural images, as images containing mountains, grass or forests. Furthermore, experimental results of colored texture clustering using images of aquifers' sedimentary porous rocks are presented and analyzed in terms of precision to verify its e ectiveness.

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In this work we propose the development of an ultrasonic anemometer using distance sensors. The wind is an important tool for studying the dynamics of the atmosphere, changes in climate and agricultural crops meteorological variable. Thus it is necessary advances in studies that provide increasingly characterizing the behavior of the wind. Currently there are several types of anemometers to measure wind speed, among which stands out due to the ultrasonic anemometer accuracy in measurements. But this device has a high cost difficult to use. Therefore, we sought to lower the cost of the ultrasonic anemometer, developing an apparatus capable of measuring wind velocity using distance sensors. In this type of anemometer wind speed is measured based on the transit time of the ultrasonic pulse, in this same distance sensors to space technique measures. Here various assemblies seeking the best configuration which could use the distance sensor to measure wind speed were made. Arrangements bulkhead and separate transducers are examples of worked assemblies that will be detailed in chapter 3. With the measures collected (with and without wind) histograms, which show the distribution of records transit time of the sound wave for each case were generated. Two of the studied configurations show favorable results regarding the use of the distance sensor as the wind speed.

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This study aimed to evaluate the microclimate changes surrounding the wind farm Macau Pilot / RN, present in the municipality of the same name. To achieve this goal made use of remote sensing techniques using Landsat - 5 TM and 7 ETM +, from which made it possible evaluation of temperature changes on the surface, this around the park in periods prior to its implementation, to the today. For evaluation of the temperature data that has been generated by applying a template was performed its correlation with field data collection and evaluated the degree of correlation, in order to confirm the validity of the data acquired by satellite. Also held was a characterization of the climate of the region based on the data of this climatological station in Macau. Once collected this data made possible the evaluation of climate change policy in the study region. After validation of the temperature models, an analysis of the generated temperature histograms was performed visually could not identify any significant change. However when analyzing the temperature data at a higher level of detail, a data pattern of behavior was detected for both periods evaluated, yet could not see a distinction between the periods of pre-operation of the park, and post-operation . From this result was levantas hypotheses to explain the behavior of the data, the first of which is the presence of moisture in the soil, and the second to the soil composition. In order to validate the hypotheses were applied PDI techniques, involving a combination of different RGB bands of Landsat 5 and the implementation of Reason bands procedure that might show the elements present on the soil surface.