User`s guide

Image Enhancement
Removing Periodic Noise from Video
Periodic noise can be introduced into a video stream during acquisition or
transmission due to electrical or electromechanical interference. In this
example, yo u remove perio dic noise from an intensity video using the 2-D FIR
Filter block. You can use this technique to remov e noise from other images or
video streams, but you might need to modify the filter coefficients to account
for the noise frequency content present in your signal:
1 Create a new Simulink model, and add to it the blocks shown in the
following table.
Block Library Quantity
Read Binary File Video and Image P rocess ing B lockset >
Sources
1
Image Data Type
Conversion
VideoandImageProcessingBlockset>
Conversions
1
2-D FIR Filter Video and Image P rocessing Blockset >
Filterin g
1
Video Viewer Video and Image Processing Blockset >
Sinks
3
Add S imulink > Math Operations
1
2 Open the Periodic noise reduction demo by typing vi pstripes at the
MATLAB com mand prompt.
3 Click-and-drag the Periodic Noise block i nto your model.
The block outputs a sinusoid with a normalized frequency that ranges
between 0.61π and 0.69π radians per sample and a phase that varies
between 0 and 3 radians. You are using this sinusoid to represe nt periodic
noise.
4 Place the blocks so that your model resembles the following figure. The
unconnected ports disappear when you set block parameters.
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