Ejemplo: transformadas wavelet

Funciones > Transformadas y filtros > Ejemplo: transformadas wavelet

Utilice las funciones de transformadas wavelet para comprimir datos.

1. Defina una señal de onda cuadrada donde:

2. Evalúe el n y trace la señal S:

En el rango de 0 a 255, la señal S tiene una amplitud de 1 para todos los valores de n (de 96 a 160), y una amplitud de cero en los demás casos.

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3. Utilice la función wave para calcular la transformada wavelet de la señal S:

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4. Calcule el número de niveles que contiene esta transformada:

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5. Use las funciones submatrix y floor para hacerse una idea de la importancia relativa de cada nivel:

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6. Trace varios niveles de coeficientes simultáneamente:

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7. Represente la señal con menos datos mediante las siguientes dos acciones:

a. Ponga a cero los coeficientes de los niveles más altos.

b. Calcule la transformada wavelet inversa de los nuevos vectores de coeficientes.

El primer nivel en el que los coeficientes se definen en cero (L < 7) podría variar.

8. Use la función iwave para recuperar la señal original:

9. Trace y compare la señal original con la señal transformada:

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Esta técnica ofrece una forma de comprimir los datos necesarios para representar una señal.

Temas relacionados

Transformadas wavelet

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