Bsoft function

img_ctf_rough_fit

Source:

src/img/img_ctf.c

Description:

Determines the approximate defocus, baseline and envelope.

Algorithm: 

	The radial power spectrum and a moving average of itself are calculated.

	A range of defocus values are selected and the minima (zeroes) for each

	calculated. The correct approximate defocus is determined by comparing

	the radial power spectrum with its moving average. The objective 

	function is:

		R = sum(rps/marps)

		where:  rps:	radial power spectrum

		        marps:  moving average of the rps

				the sum is over all minima in the given resolution range

	The baseline is fitted to the minima and the envelope to the maxima.

	Input: Power spectrum (not its logarithm).

	The resultant CTF parameters are returned in the image structure.

Arguments:

Bimage* pimage structure.
CTF* em_ctfCTF parameter structure.
float loreslow resolution limit.
float hireshigh resolution limit

Returns:

double R factor.

Prototype:

double img_ctf_rough_fit(Bimage* p, CTF* em_ctf, float lores, float hires)

Functions used:

bfree
ctf_zeroes

Other objects included:

struct Bimage
struct Bmarker

Generated by bdoc.pl on Mon Jun 15 11:47:48 2009

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