fourint    Interpolate up by Fourier padding (2D and 3D)  

 

File format: SPIDER Fourier

USAGE:     fourint

          .INPUT FILE: image4086
          [Enter the name of the input file. This can be a 2d image or a 
	   3D volume. The dimensions in all directions must be the same 
	   (square of cube).(future update envisioned)]

          .OUTPUT FILE: bigimage4086
          [Enter name of output file.]

          .Enlargement factor: 2.
	  [Enter the enlargement factor. Internally the program determines if
	   the resulting dimensions are legal for the fourier transform 
	   implemented here (or in SPIDER), which requires to be a product
	   of prime number lower/equal 7. If this is not the case, the next
	   higher compatible dimensions will be used, and the adjusted
	   enlargement factor will be echoed.]

NOTES:	   If your image/volume has energy up to the Nyquist frequency you need
	   to low-pass filter your image/volume prior to Fourier up
	   interpolation, otherwise fringes may occur. A Fermi low-pass filter
	   with a radius of 0.3 and a temperature of 0.02 seems to be working
	   well. 
	   
Programs:  fourup.f

Author(s): M. Radermacher