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FourierDCTFilter[image,t]

reduces noise in image by locally thresholding the discrete cosine transforms of overlapping subimages, using the hard threshold t.

Details
Details and Options Details and Options
Examples  
Basic Examples  
Scope  
Data  
Parameters  
Applications  
Possible Issues  
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FourierDCTFilter

FourierDCTFilter[image,t]

reduces noise in image by locally thresholding the discrete cosine transforms of overlapping subimages, using the hard threshold t.

Details

  • FourierDCTFilter works with arbitrary 2D and 3D images.
  • Local DCT thresholding is applied to all overlapping 16×16 partitions of image. The value of each output pixel is the average of the corresponding pixel in all partitions that include the pixel.
  • For multichannel images, color channels are decorrelated by effectively using a 3D DCT.
  • In FourierDCTFilter[image,t], the threshold value t is typically in the range 0 to 1.

Examples

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Basic Examples  (1)

Reduce noise in an angiography image:

Scope  (3)

Data  (2)

Filter a multichannel image:

Denoise a 3D image:

Parameters  (1)

Specify the hard threshold:

Applications  (3)

Remove salt-and-pepper noise:

Remove Gaussian color noise from an image:

Unsharp masking using FourierDCTFilter:

Possible Issues  (1)

Timings grow rapidly with the dimensions of a 3D image:

Wolfram Research (2012), FourierDCTFilter, Wolfram Language function, https://reference.wolfram.com/language/ref/FourierDCTFilter.html (updated 2014).

Text

Wolfram Research (2012), FourierDCTFilter, Wolfram Language function, https://reference.wolfram.com/language/ref/FourierDCTFilter.html (updated 2014).

CMS

Wolfram Language. 2012. "FourierDCTFilter." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2014. https://reference.wolfram.com/language/ref/FourierDCTFilter.html.

APA

Wolfram Language. (2012). FourierDCTFilter. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/FourierDCTFilter.html

BibTeX

@misc{reference.wolfram_2025_fourierdctfilter, author="Wolfram Research", title="{FourierDCTFilter}", year="2014", howpublished="\url{https://reference.wolfram.com/language/ref/FourierDCTFilter.html}", note=[Accessed: 16-August-2025]}

BibLaTeX

@online{reference.wolfram_2025_fourierdctfilter, organization={Wolfram Research}, title={FourierDCTFilter}, year={2014}, url={https://reference.wolfram.com/language/ref/FourierDCTFilter.html}, note=[Accessed: 16-August-2025]}