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Diffstat (limited to 'help/en_US/medfilt1.xml')
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diff --git a/help/en_US/medfilt1.xml b/help/en_US/medfilt1.xml index 2766e88..2760fe9 100644 --- a/help/en_US/medfilt1.xml +++ b/help/en_US/medfilt1.xml @@ -18,68 +18,107 @@ <refnamediv> <refname>medfilt1</refname> <refpurpose>1D median filtering</refpurpose> + <para> </para> </refnamediv> <refsynopsisdiv> <title>Calling Sequence</title> <synopsis> + y = medfilt1(x) + y = medfilt1(x, n) + y = medfilt1(x, n, dim) + y = medfitl1(__, nanflag, padding) </synopsis> + <para> </para> </refsynopsisdiv> <refsection> <title>Description</title> <para> y = medfilt1(x) -Applies a 3rd order 1-dimensional median filter to input x along the -first non-zero dimension. The function appropriately pads the signal + </para> +<para>Applies a 3rd order 1-dimensional median filter to input x along the +first non-zero dimension.</para> + <para>The function appropriately pads the signal with zeros at the endings. For a segment, a median is calculated as the middle value (average of two middle values) for odd number -number (even number) of data points. -y = medfilt1(x,n) -Applies a nth order 1-dimensional median filter. -y = medfilt1(x,n,dim) -Applies the median filter along the n-th dimension -y = medfilt1(__, nanflag, padding) -nanflag specifies how NaN values are treated. padding specifies the -type of filtering to be performed at the signal edges. - </para> - <para> -</para> +number (even number) of data points.</para> +<para> </para> +<para>y = medfilt1(x,n)</para> +<para>Applies a nth order 1-dimensional median filter.</para> +<para> </para> +<para>y = medfilt1(x,n,dim)</para> +<para>Applies the median filter along the n-th dimension</para> +<para> </para> +<para>y = medfilt1(__, nanflag, padding)</para> +<para>nanflag specifies how NaN values are treated. padding specifies the +type of filtering to be performed at the signal edges.</para> + + <para> </para> </refsection> <refsection> <title>Parameters</title> <variablelist> <varlistentry><term>x:</term> - <listitem><para> int | double</para></listitem></varlistentry> + <listitem><para> int | double</para> <para>Input signal.</para></listitem></varlistentry> <varlistentry><term>n:</term> - <listitem><para> positive integer scalar</para></listitem></varlistentry> + <listitem><para> positive integer, scalar</para><para> + Filter order. </para> + <para> Defaults to 3.The order of the median filter. Must be less than + (length of the signal) where signals are 1D vectors along the + dimension of x to be filtered </para></listitem></varlistentry> <varlistentry><term>dim:</term> - <listitem><para> positive integer scalar</para></listitem></varlistentry> + <listitem><para> positive integer scalar</para><para> + Dimension to filter along. </para> + <para> Defaults to first non-singleton dimension of x</para></listitem></varlistentry> <varlistentry><term>nanflag:</term> - <listitem><para> 'includenan' (default) | 'omitnan'</para></listitem></varlistentry> - <varlistentry><term>* includenan:</term> - <listitem><para> Filtering such that the median of any segment</para></listitem></varlistentry> - <varlistentry><term>* omitnan:</term> - <listitem><para> Filtering with NaNs omitted in each segment. If a segment</para></listitem></varlistentry> + <listitem><para> 'includenan' (default) | 'omitnan'</para> <para> + NaN condition.</para> + <para> * includenan: Filtering such that the median of any segment containing a NaN is also a NaN. </para> + <para>* omitnan: Filtering with NaNs omitted in each segment. If a segment contains all NaNs, the result is NaN</para> +</listitem></varlistentry> + <varlistentry><term>y:</term> - <listitem><para> int | double</para></listitem></varlistentry> + <listitem><para> int | double</para><para> + The filtered signal.</para> + <para>y has the same size as x</para></listitem></varlistentry> </variablelist> + <para> </para> </refsection> <refsection> <title>Examples</title> <programlisting role="example"><![CDATA[ -1) Noise supression using median filtering -fs = 1e3; -t = 1:1/fs:1; -s = sin(2*%pi*2*t)+ cos(2*%pi*5*t); -// Adding noise -x = s + 0.1*randn(size(s)); -y = medfilt1(x); +//Generate a sinusoidal signal sampled for 1 second at 100 Hz. Add a higher-frequency sinusoid to simulate noise. +fs = 100; +t = 0:1/fs:1; +x = sin(2*%pi*t*3)+0.25*sin(2*%pi*t*40); +//Use a 10th-order median filter to smooth the signal. Plot the result. +y = medfilt1(x,10); +plot(t,x,t,y) +legend('Original','Filtered'); +y = round(y*10000)/10000; +y = y' ]]></programlisting> + +<scilab:image> +//Generate a sinusoidal signal sampled for 1 second at 100 Hz. Add a higher-frequency sinusoid to simulate noise. +fs = 100; +t = 0:1/fs:1; +x = sin(2*%pi*t*3)+0.25*sin(2*%pi*t*40); + +//Use a 10th-order median filter to smooth the signal. Plot the result. +y = medfilt1(x,10); +plot(t,x,t,y) +legend('Original','Filtered'); +y = round(y*10000)/10000; +y = y' +</scilab:image> + + </refsection> <refsection> |