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


  • 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.


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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, (updated 2014).


Wolfram Research (2012), FourierDCTFilter, Wolfram Language function, (updated 2014).


Wolfram Language. 2012. "FourierDCTFilter." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2014.


Wolfram Language. (2012). FourierDCTFilter. Wolfram Language & System Documentation Center. Retrieved from


@misc{reference.wolfram_2024_fourierdctfilter, author="Wolfram Research", title="{FourierDCTFilter}", year="2014", howpublished="\url{}", note=[Accessed: 18-July-2024 ]}


@online{reference.wolfram_2024_fourierdctfilter, organization={Wolfram Research}, title={FourierDCTFilter}, year={2014}, url={}, note=[Accessed: 18-July-2024 ]}