make_extended¶
- turbustat.simulator.make_extended(imsize, powerlaw=2.0, theta=0.0, ellip=1.0, return_fft=False, full_fft=True, randomseed=32768324)[source]¶
Generate a 2D power-law image with a specified index and random phases.
Adapted from https://github.com/keflavich/image_registration. Added ability to make the power spectra elliptical. Also changed the random sampling so the random phases are Hermitian (and the inverse FFT gives a real-valued image).
- Parameters:
- imsizeint
Array size.
- powerlawfloat, optional
Powerlaw index.
- thetafloat, optional
Position angle of major axis in radians. Has no effect when ellip==1.
- ellipfloat, optional
Ratio of the minor to major axis. Must be > 0 and <= 1. Defaults to the circular case (ellip=1).
- return_fftbool, optional
Return the FFT instead of the image. The full FFT is returned, including the redundant negative phase phases for the RFFT.
- full_fftbool, optional
When
return_fft=True, the full FFT, with negative frequencies, will be returned. Iffull_fft=False, the RFFT is returned.- randomseed: int, optional
Seed for random number generator.
- Returns:
- newmapnp.ndarray
Two-dimensional array with the given power-law properties.
- full_powermapnp.ndarray
The 2D array in Fourier space. The zero-frequency is shifted to the centre.