Functions | |
void | imProcessFFT (const imImage *src_image, imImage *dst_image) |
void | imProcessIFFT (const imImage *src_image, imImage *dst_image) |
void | imProcessFFTraw (imImage *image, int inverse, int center, int normalize) |
void | imProcessSwapQuadrants (imImage *image, int center2origin) |
Forward FFT.
The result has its lowest frequency at the center of the image.
This is an unnormalized fft.
Images must be of the same size. Target image must be of type float complex.
im.ProcessFFT(src_image: imImage, dst_image: imImage) [in Lua 5]
im.ProcessFFTNew(image: imImage) -> new_image: imImage [in Lua 5]
Inverse FFT.
The image has its lowest frequency restored to the origin before the transform.
The result is normalized by (width*height).
Images must be of the same size and both must be of type float complex.
im.ProcessIFFT(src_image: imImage, dst_image: imImage) [in Lua 5]
im.ProcessIFFTNew(image: imImage) -> new_image: imImage [in Lua 5]
void imProcessFFTraw | ( | imImage * | image, | |
int | inverse, | |||
int | center, | |||
int | normalize | |||
) |
Raw in-place FFT (forward or inverse).
The lowest frequency can be centered after forward, or can be restored to the origin before inverse.
The result can be normalized after the transform by sqrt(w*h) [1] or by (w*h) [2], or left unnormalized [0].
Images must be of the same size and both must be of type float complex.
im.ProcessFFTraw(image: imImage, inverse: number, center: number, normalize: number) [in Lua 5]
void imProcessSwapQuadrants | ( | imImage * | image, | |
int | center2origin | |||
) |
Auxiliary function for the raw FFT.
This is the function used internally to change the lowest frequency position in the image.
If the image size has even dimensions the flag "center2origin" is useless. But if it is odd, you must specify if its from center to origin (usually used before inverse) or from origin to center (usually used after forward).
Notice that this function is used for images in the the frequency domain.
Image type must be float complex.
im.ProcessSwapQuadrants(image: imImage, center2origin: number) [in Lua 5]