#include <math.h>
#include "allheaders.h"

Macros
#define	DEBUG_BOXES 0

Functions
l_ok	pixQuadtreeMean (PIX pixs, l_int32 nlevels, PIX pix_ma, FPIXA **pfpixa)

l_ok	pixQuadtreeVariance (PIX pixs, l_int32 nlevels, PIX pix_ma, DPIX dpix_msa, FPIXA pfpixa_v, FPIXA *pfpixa_rv)

l_ok	pixMeanInRectangle (PIX pixs, BOX box, PIX pixma, l_float32 pval)

l_ok	pixVarianceInRectangle (PIX pixs, BOX box, PIX pix_ma, DPIX dpix_msa, l_float32 pvar, l_float32 prvar)

BOXAA *	boxaaQuadtreeRegions (l_int32 w, l_int32 h, l_int32 nlevels)

l_ok	quadtreeGetParent (FPIXA fpixa, l_int32 level, l_int32 x, l_int32 y, l_float32 pval)

l_ok	quadtreeGetChildren (FPIXA fpixa, l_int32 level, l_int32 x, l_int32 y, l_float32 pval00, l_float32 pval10, l_float32 pval01, l_float32 *pval11)

l_int32	quadtreeMaxLevels (l_int32 w, l_int32 h)

PIX *	fpixaDisplayQuadtree (FPIXA *fpixa, l_int32 factor, l_int32 fontsize)

Detailed Description


     Top level quadtree linear statistics
         l_int32   pixQuadtreeMean()
         l_int32   pixQuadtreeVariance()

     Statistics in an arbitrary rectangle
         l_int32   pixMeanInRectangle()
         l_int32   pixVarianceInRectangle()

     Quadtree regions
         BOXAA    *boxaaQuadtreeRegions()

     Quadtree access
         l_int32   quadtreeGetParent()
         l_int32   quadtreeGetChildren()
         l_int32   quadtreeMaxLevels()

     Display quadtree
         PIX      *fpixaDisplayQuadtree()


 There are many other statistical quantities that can be computed
 in a quadtree, such as rank values, and these can be added as
 the need arises.

 Similar results that can approximate a single level of the quadtree
 can be generated by pixGetAverageTiled().  There we specify the
 tile size over which the mean, mean square, and root variance
 are generated; the results are saved in a (reduced size) pix.
 Because the tile dimensions are integers, it is usually not possible
 to obtain tilings that are a power of 2, as required for quadtrees.

Definition in file quadtree.c.

Macro Definition Documentation

◆ DEBUG_BOXES

#define DEBUG_BOXES 0

Definition at line 72 of file quadtree.c.

Function Documentation

◆ boxaaQuadtreeRegions()

BOXAA * boxaaQuadtreeRegions	(	l_int32	w,
		l_int32	h,
		l_int32	nlevels )

boxaaQuadtreeRegions()

Parameters

[in]	w,h	size of pix that is being quadtree-ized
[in]	nlevels	number of levels in quadtree

Returns: baa for quadtree regions at each level, or NULL on error

Notes:
     (1) The returned boxaa has nlevels of boxa, each containing
         the set of rectangles at that level.  The rectangle at
         level 0 is the entire region; at level 1 the region is
         divided into 4 rectangles, and at level n there are n^4
         rectangles.
     (2) At each level, the rectangles in the boxa are in "raster"
         order, with LR (fast scan) and TB (slow scan).

Definition at line 445 of file quadtree.c.

References L_INSERT.

Referenced by pixQuadtreeMean(), and pixQuadtreeVariance().

◆ fpixaDisplayQuadtree()

PIX * fpixaDisplayQuadtree	(	FPIXA *	fpixa,
		l_int32	factor,
		l_int32	fontsize )

fpixaDisplayQuadtree()

Parameters

[in]	fpixa	mean, variance or root variance
[in]	factor	replication factor at lowest level
[in]	fontsize	4, ... 20

Returns: pixd 8 bpp, mosaic of quadtree images, or NULL on error

Notes:
     (1) The mean and root variance fall naturally in the 8 bpp range,
         but the variance is typically outside the range.  This
         function displays 8 bpp pix clipped to 255, so the image
         pixels will mostly be 255 (white).

Definition at line 644 of file quadtree.c.

References L_ADD_BELOW, L_CLIP_TO_ZERO, L_CLONE, and L_INSERT.

◆ pixMeanInRectangle()

l_ok pixMeanInRectangle	(	PIX *	pixs,
		BOX *	box,
		PIX *	pixma,
		l_float32 *	pval )

pixMeanInRectangle()

Parameters

[in]	pixs	8 bpp
[in]	box	region to compute mean value
[in]	pixma	mean accumulator
[out]	pval	mean value

Returns: 0 if OK, 1 on error

Notes:
     (1) This function is intended to be used for many rectangles
         on the same image.  It can find the mean within a
         rectangle in O(1), independent of the size of the rectangle.

Definition at line 265 of file quadtree.c.

Referenced by pixQuadtreeMean().

◆ pixQuadtreeMean()

l_ok pixQuadtreeMean	(	PIX *	pixs,
		l_int32	nlevels,
		PIX *	pix_ma,
		FPIXA **	pfpixa )

pixQuadtreeMean()

Parameters

[in]	pixs	8 bpp, no colormap
[in]	nlevels	in quadtree; max allowed depends on image size
[in]	pix_ma	input mean accumulator; can be null
[out]	pfpixa	mean values in quadtree

Returns: 0 if OK, 1 on error

Notes:
     (1) The returned fpixa has nlevels of fpix, each containing
         the mean values at its level.  Level 0 has a
         single value; level 1 has 4 values; level 2 has 16; etc.

Definition at line 96 of file quadtree.c.

References boxaaQuadtreeRegions(), L_CLONE, L_INSERT, pixMeanInRectangle(), and quadtreeMaxLevels().

◆ pixQuadtreeVariance()

l_ok pixQuadtreeVariance	(	PIX *	pixs,
		l_int32	nlevels,
		PIX *	pix_ma,
		DPIX *	dpix_msa,
		FPIXA **	pfpixa_v,
		FPIXA **	pfpixa_rv )

pixQuadtreeVariance()

Parameters

[in]	pixs	8 bpp, no colormap
[in]	nlevels	in quadtree
[in]	pix_ma	input mean accumulator; can be null
[in]	dpix_msa	input mean square accumulator; can be null
[out]	pfpixa_v	[optional] variance values in quadtree
[out]	pfpixa_rv	[optional] root variance values in quadtree

Returns: 0 if OK, 1 on error

Notes:
     (1) The returned fpixav and fpixarv have nlevels of fpix,
         each containing at the respective levels the variance
         and root variance values.

Definition at line 171 of file quadtree.c.

References boxaaQuadtreeRegions(), L_CLONE, L_INSERT, pixVarianceInRectangle(), and quadtreeMaxLevels().

◆ pixVarianceInRectangle()

l_ok pixVarianceInRectangle	(	PIX *	pixs,
		BOX *	box,
		PIX *	pix_ma,
		DPIX *	dpix_msa,
		l_float32 *	pvar,
		l_float32 *	prvar )

pixVarianceInRectangle()

Parameters

[in]	pixs	8 bpp
[in]	box	region to compute variance and/or root variance
[in]	pix_ma	mean accumulator
[in]	dpix_msa	mean square accumulator
[out]	pvar	[optional] variance
[out]	prvar	[optional] root variance

Returns: 0 if OK, 1 on error

Notes:
     (1) This function is intended to be used for many rectangles
         on the same image.  It can find the variance and/or the
         square root of the variance within a rectangle in O(1),
         independent of the size of the rectangle.

Definition at line 339 of file quadtree.c.

Referenced by pixQuadtreeVariance().

◆ quadtreeGetChildren()

l_ok quadtreeGetChildren	(	FPIXA *	fpixa,
		l_int32	level,
		l_int32	x,
		l_int32	y,
		l_float32 *	pval00,
		l_float32 *	pval10,
		l_float32 *	pval01,
		l_float32 *	pval11 )

quadtreeGetChildren()

Parameters

[in]	fpixa	mean, variance or root variance
[in]	level,x,y	of current pixel
[out]	pval00,pval01,pval10,pval11	four child pixel values

Returns: 0 if OK, 1 on error

Notes:
     (1) Check return value for error.  On error, all return vals are 0.0.
     (2) The returned child pixels are located at:
            level + 1
            (2x, 2y), (2x+1, 2y), (2x, 2y+1), (2x+1, 2y+1)

Definition at line 565 of file quadtree.c.

◆ quadtreeGetParent()

l_ok quadtreeGetParent	(	FPIXA *	fpixa,
		l_int32	level,
		l_int32	x,
		l_int32	y,
		l_float32 *	pval )

quadtreeGetParent()

Parameters

[in]	fpixa	mean, variance or root variance
[in]	level,x,y	of current pixel
[out]	pval	parent pixel value, or 0.0 on error

Returns: 0 if OK, 1 on error

Notes:
     (1) Check return value for error.  On error, val is returned as 0.0.
     (2) The parent is located at:
            level - 1
            (x/2, y/2)

Definition at line 524 of file quadtree.c.

◆ quadtreeMaxLevels()

l_int32 quadtreeMaxLevels	(	l_int32	w,
		l_int32	h )

quadtreeMaxLevels()

Parameters

[in] w,h dimensions of image

Returns: maxlevels maximum number of levels allowed, or -1 on error

Notes:
     (1) The criterion for maxlevels is that the subdivision not
         go down below the single pixel level.  The 1.5 factor
         is intended to keep any rectangle from accidentally
         having zero dimension due to integer truncation.

Definition at line 609 of file quadtree.c.

Referenced by pixQuadtreeMean(), and pixQuadtreeVariance().

Macros

Functions

Detailed Description

Macro Definition Documentation

◆ DEBUG_BOXES

Function Documentation

◆ boxaaQuadtreeRegions()

◆ fpixaDisplayQuadtree()

◆ pixMeanInRectangle()

◆ pixQuadtreeMean()

◆ pixQuadtreeVariance()

◆ pixVarianceInRectangle()

◆ quadtreeGetChildren()

◆ quadtreeGetParent()

◆ quadtreeMaxLevels()