arImageProc.c File Reference

#include <string.h>
#include <ARX/AR/arImageProc.h>

Include dependency graph for arImageProc.c:

Functions
ARImageProcInfo *	arImageProcInit (const int xsize, const int ysize)
	Initialise image processing. More...
void	arImageProcFinal (ARImageProcInfo *ipi)
	Finish image processing and free memory. More...
int	arImageProcLumaHist (ARImageProcInfo *ipi, const ARUint8 *__restrict dataPtr)
	Calculate luminance histogram. More...
unsigned char *	arImageProcGetHistImage (ARImageProcInfo *ipi)
	Get luminance histogram as an image. More...
int	arImageProcLumaHistAndCDF (ARImageProcInfo *ipi, const ARUint8 *__restrict dataPtr)
	Calculate image histogram and cumulative density function. More...
int	arImageProcLumaHistAndCDFAndPercentile (ARImageProcInfo *ipi, const ARUint8 *__restrict dataPtr, const float percentile, unsigned char *value_p)
	Calculate image histogram, cumulative density function, and luminance value at a given histogram percentile. More...
int	arImageProcLumaHistAndCDFAndMedian (ARImageProcInfo *ipi, const ARUint8 *__restrict dataPtr, unsigned char *value_p)
	Calculate image histogram, cumulative density function, and median luminance value. More...
int	arImageProcLumaHistAndOtsu (ARImageProcInfo *ipi, const ARUint8 *__restrict dataPtr, unsigned char *value_p)
	Calculate image histogram, and binarize image using Otsu's method for foreground/background separation. More...
int	arImageProcLumaHistAndBoxFilterWithBias (ARImageProcInfo *ipi, const ARUint8 *__restrict dataPtr, const int boxSize, const int bias)
	Calculate image histogram, and box filter image. More...
int	arImageProcLumaHistAndCDFAndLevels (ARImageProcInfo *ipi, const ARUint8 *__restrict dataPtr)
	Calculate image histogram, cumulative density function, and minimum and maximum luminance values. More...

Function Documentation

arImageProcFinal()

void arImageProcFinal

(

ARImageProcInfo *

ipi

)

Finish image processing and free memory.

When processing is complete, the ARImageProcInfo structure should be disposed of by calling this function.

Parameters

ipi	ARImageProcInfo structure to be disposed of, as created by arImageProcInit.

See also

arImageProcInit

arImageProcGetHistImage()

unsigned char * arImageProcGetHistImage

(

ARImageProcInfo *

ipi

)

Get luminance histogram as an image.

Returns a pointer to a buffer containing a 256x256 8-bit grayscale texture. The texture can be uploaded to an OpenGL texture with the calls:

buf = arImageProcGetHistImage(ipi);
if (buf) {
    glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, 256, 256, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, buf);
    free(buf);
}

After uploading, the texture can be drawn as with any other OpenGL texture.

Parameters

ipi	ARImageProcInfo structure holding the most recently processed histogram, as generated by arImageProcLumaHist etc.

Returns

Pointer to the texture data.

arImageProcInit()

ARImageProcInfo * arImageProcInit	(	const int	xsize,
		const int	ysize
	)

Initialise image processing.

This function creates the ARImageProcInfo structure required for other image processing functions. The size of the image that will be processed is fixed by this call.

Parameters

xsize	Width of the images that will be processed, in pixels.
ysize	Height of the images that will be processed, in pixels.

Returns

Pointer to the ARImageProcInfo structure. When processing is complete, this structure should be disposed of by calling arImageProcFinal.

See also

arImageProcFinal

arImageProcLumaHist()

int arImageProcLumaHist	(	ARImageProcInfo *	ipi,
		const ARUint8 *__restrict	dataPtr
	)

Calculate luminance histogram.

Parameters

ipi	ARImageProcInfo structure describing the format of the image to be processed, as created by arImageProcInit.

On macOS and iOS, the calculation is accelerated using the Accelerate framework.

Returns

0 in case of success, or a value less than 0 in case of error.

arImageProcLumaHistAndBoxFilterWithBias()

int arImageProcLumaHistAndBoxFilterWithBias	(	ARImageProcInfo *	ipi,
		const ARUint8 *__restrict	dataPtr,
		const int	boxSize,
		const int	bias
	)

Calculate image histogram, and box filter image.

See https://developer.apple.com/library/ios/documentation/Performance/Reference/vImage_convolution/ On macOS and iOS, the calculation is accelerated using the Accelerate framework.

Parameters

ipi	ARImageProcInfo structure describing the format of the image to be processed, as created by arImageProcInit.

Returns

0 in case of success, or a value less than 0 in case of error.

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arImageProcLumaHistAndCDF()

int arImageProcLumaHistAndCDF	(	ARImageProcInfo *	ipi,
		const ARUint8 *__restrict	dataPtr
	)

Calculate image histogram and cumulative density function.

Parameters

ipi	ARImageProcInfo structure describing the format of the image to be processed, as created by arImageProcInit.

Returns

0 in case of success, or a value less than 0 in case of error.

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arImageProcLumaHistAndCDFAndLevels()

int arImageProcLumaHistAndCDFAndLevels	(	ARImageProcInfo *	ipi,
		const ARUint8 *__restrict	dataPtr
	)

Calculate image histogram, cumulative density function, and minimum and maximum luminance values.

Parameters

ipi	ARImageProcInfo structure describing the format of the image to be processed, as created by arImageProcInit.

Returns

0 in case of success, or a value less than 0 in case of error.

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arImageProcLumaHistAndCDFAndMedian()

int arImageProcLumaHistAndCDFAndMedian	(	ARImageProcInfo *	ipi,
		const ARUint8 *__restrict	dataPtr,
		unsigned char *	value_p
	)

Calculate image histogram, cumulative density function, and median luminance value.

Parameters

ipi	ARImageProcInfo structure describing the format of the image to be processed, as created by arImageProcInit.

Returns

0 in case of success, or a value less than 0 in case of error.

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arImageProcLumaHistAndCDFAndPercentile()

int arImageProcLumaHistAndCDFAndPercentile	(	ARImageProcInfo *	ipi,
		const ARUint8 *__restrict	dataPtr,
		const float	percentile,
		unsigned char *	value_p
	)

Calculate image histogram, cumulative density function, and luminance value at a given histogram percentile.

Parameters

ipi	ARImageProcInfo structure describing the format of the image to be processed, as created by arImageProcInit.

Returns

0 in case of success, or a value less than 0 in case of error.

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arImageProcLumaHistAndOtsu()

int arImageProcLumaHistAndOtsu	(	ARImageProcInfo *	ipi,
		const ARUint8 *__restrict	dataPtr,
		unsigned char *	value_p
	)

Calculate image histogram, and binarize image using Otsu's method for foreground/background separation.

See http://en.wikipedia.org/wiki/Otsu's_method fore more information.

Parameters

ipi	ARImageProcInfo structure describing the format of the image to be processed, as created by arImageProcInit.

Returns

0 in case of success, or a value less than 0 in case of error.

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