Sumários
Teorema da convolução
10 outubro 2013, 12:30 • João Miguel Sanches
Teorema da convolução Convolução de Sequencias longas
Filtragem
9 outubro 2013, 12:30 • João Miguel Sanches
In this work two types of linear and non linear filters will be used to attenuate or, if possible, to remove the noise corrupting an audio file. The noise corrupting the music is salt and pepper to simulate the traditional noise present in the old vinyl long play records. This type of noise, non additive nor Gaussian, is characterized by maximum and minimum saturations at random instants. The removing of this type of noise using linear filtering it is usually not efficient. Conversely, non linear filtering is usually quite efficient when dealing with this type of non-linear degradation process, e.g., the median filter. The output of a basic 1D median filter is the median value of the set of values composed by the intensities of the pixels in the neighborhood of the current sample plus the current sample, that is, the median of the pixel set contained in the 2M + 1 dimension neighboring window. In this strategy the noisy pixels tend to accumulate at the extrema of the window which leads to its
Filtragem
9 outubro 2013, 10:30 • João Miguel Sanches
In this work two types of linear and non linear filters will be used to attenuate or, if possible, to remove the noise corrupting an audio file. The noise corrupting the music is salt and pepper to simulate the traditional noise present in the old vinyl long play records. This type of noise, non additive nor Gaussian, is characterized by maximum and minimum saturations at random instants. The removing of this type of noise using linear filtering it is usually not efficient. Conversely, non linear filtering is usually quite efficient when dealing with this type of non-linear degradation process, e.g., the median filter. The output of a basic 1D median filter is the median value of the set of values composed by the intensities of the pixels in the neighborhood of the current sample plus the current sample, that is, the median of the pixel set contained in the 2M + 1 dimension neighboring window. In this strategy the noisy pixels tend to accumulate at the extrema of the window which leads to its
Transformadas
3 outubro 2013, 12:30 • João Miguel Sanches
Transformadas
Transformada de Fourier continua e discreta de sinais discretos