dataops.c File Reference

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "dataops.h"

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Defines
#define	MIN(a, b)   ( (a)<(b)? (a) : (b) )
#define	MAX(a, b)   ( (a)>(b)? (a) : (b) )
#define	ELEM_SWAP(a, b)   { register float t=(a);(a)=(b);(b)=t; }
Functions
void	make_overlay (double theta, int npixx, int npixy, float *overlay, char *arrowfile)
	Make an overlay containing N-E axes.
void	scaleasinh (float *buffer, int npixx, int npixy, float median, float minval, float maxval, float sdev, double theta, int neoverlay, float contrast, char *coordfile)
	Apply asinh scaling to the image.
float	get_binned (int ix, int iy, int binsize, int npixx, float *buffer)
void	get_zscales (float contrast, int n1, int n2, float *buffer, float *z1, float *z2)
void	get_maxmin (float *buffer, long long npixels, float *min, float *max, float *median, float *mean, float *sdev)
	Calculate max and min from a subset of the fits image pixels.
int	compare (const float *v1, const float *v2)
void	lsfit (int ndata, float *xdata, float *ydata, float *a, float *b)
float	quick_select (float arr[], long long n)

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Detailed Description

Author:

Ian Bond, IfA, University of Edinburgh

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Define Documentation

#define ELEM_SWAP	(	a,
		b		)	{ register float t=(a);(a)=(b);(b)=t; }

Referenced by quick_select().

#define MAX	(	a,
		b		)	( (a)>(b)? (a) : (b) )

Referenced by get_maxmin(), make_overlay(), and scaleasinh().

#define MIN	(	a,
		b		)	( (a)<(b)? (a) : (b) )

Referenced by scaleasinh().

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Function Documentation

int compare	(	const float *	v1,
		const float *	v2
	)

Comparison operation that is used in conjunction with the standard C library qsort function.

Referenced by get_zscales().

float get_binned	(	int	ix,
		int	iy,
		int	binsize,
		int	npixx,
		float *	buffer
	)

Bin the image buffer data at the given pixel (ix, iy) and given binsize

Referenced by get_jbuffer().

void get_maxmin	(	float *	buffer,
		long long	npixels,
		float *	min,
		float *	max,
		float *	median,
		float *	mean,
		float *	sdev
	)

Calculate max and min from a subset of the fits image pixels.

References MAX, and quick_select().

Referenced by mef2jpeg().

void get_zscales	(	float	contrast,
		int	n1,
		int	n2,
		float *	buffer,
		float *	z1,
		float *	z2
	)

Calculate z1 and z2 using the "z scale" algorithm for a given contrast. The calculation of z1 and z2 is done by implementating the algorithm used in IRAF. See the IRAF documentation for "display" for more details.

References compare(), and lsfit().

void lsfit	(	int	ndata,
		float *	xdata,
		float *	ydata,
		float *	a,
		float *	b
	)

Implement the least squares formula on the two arrays of a and y data. Here we have y = a + bx.

Referenced by get_zscales().

void make_overlay	(	double	theta,
		int	npixx,
		int	npixy,
		float *	overlay,
		char *	arrowfile
	)

Make an overlay containing N-E axes.

References MAX.

Referenced by scaleasinh().

float quick_select	(	float	arr[],
		long long	n
	)

References ELEM_SWAP.

Referenced by get_maxmin().

void scaleasinh	(	float *	buffer,
		int	npixx,
		int	npixy,
		float	median,
		float	minval,
		float	maxval,
		float	sdev,
		double	theta,
		int	neoverlay,
		float	contrast,
		char *	coordfile
	)

Apply asinh scaling to the image.

References make_overlay(), MAX, and MIN.

Referenced by mef2jpeg().