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Image Transforms

Perform Fourier, discrete cosine, Radon, and fan-beam transforms

Functions

bwdistDistance transform of binary image
bwdistgeodesicGeodesic distance transform of binary image
graydistGray-weighted distance transform of grayscale image
houghHough transform
houghlinesExtract line segments based on Hough transform
houghpeaksIdentify peaks in Hough transform
dct22-D discrete cosine transform
dctmtxDiscrete cosine transform matrix
fan2paraConvert fan-beam projections to parallel-beam
fanbeamFan-beam transform
idct22-D inverse discrete cosine transform
ifanbeamInverse fan-beam transform
iradonInverse Radon transform
para2fanConvert parallel-beam projections to fan-beam
radonRadon transform
fft22-D fast Fourier transform
fftshiftShift zero-frequency component to center of spectrum
ifft22-D inverse fast Fourier transform
ifftshiftInverse zero-frequency shift

Topics

Fourier Transform

Learn about the Fourier transform and some of its applications in image processing, particularly in image filtering.

Discrete Cosine Transform

Learn about the discrete cosine transform (DCT) of an image and its applications, particularly in image compression.

Hough Transform

The Hough transform detects lines in an image, including lines tilted at arbitrary angles from vertical and horizontal. The Hough transform tends to be quick, but can exhibit artifacts.

Radon Transform

The Radon transform detects lines in an image, including lines tilted at arbitrary angles from vertical and horizontal. The Radon transform tends to be more accurate at the cost of longer computation time.

The Inverse Radon Transformation

The inverse Radon transform reconstructs an image from a set of parallel-beam projection data across many projection angles.

Detect Lines Using the Radon Transform

This example shows how to detect lines and identify the strongest lines in an image using the Radon transform.

Fan-Beam Projection

Use fan-beam projection and reconstruction when projections of an image are acquired along paths radiating from a point source. Medical tomography is a common application of fan-beam projection.

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