Modules
	RLC Moments

Functions
void	rlc_feature (feature f, U16 rlc, I32 color)
	Calculate Compound Features in Unlabelled Run Length Code (RLC). More...

I32	rl_ftr2 (U16 rlc, ftr f, U32 n)
	Calculate Object Features in the Labelled RLC. More...

I32	rl_ftr3 (U16 rlc, ftr f, U32 n)
	Calculate Object Features in the Labelled RLC (Subpixel Version). More...

I32	rlc_feret (U16 src, F32 alpha, F32 fer)
	Calculate Feret Diameters of all Objects in Labelled RLC. More...

I32	rlc_minmax_feret (U16 pRlc, I32 nsteps, F32 fMinAngleRad, F32 fMaxAngleRad, F32 minferets, F32 minangles, F32 maxferets, F32 *maxangles)
	Calculate Minimum and Maximum Ferets for All Objects in Labelled RLC. More...

Detailed Description

For a description see the section Features.

Function Documentation

◆ rlc_feature()

void rlc_feature	(	feature *	f,
		U16 *	rlc,
		I32	color
	)

The function calculates features in the unlabelled RLC. The parameter color can be used to specify if the features for all black (color = 0) or all white (color = 0xFFFF) pixels of the RLC should be calculated. All pixels of a given color (black or white) are included. There is no differentiation according to objects. The following features are calculated:

area: Pixel Count of the chosen Color.
x_center: x-Coordinate of the Center of Gravity.
y_center: y-Coordinate of the Center of Gravity.
x_min: Smallest x Coordinate (Bounding Box).
x_max: Largest x Coordinate (Bounding Box).
y_min: Smallest y Coordinate (Bounding Box).
y_max: Largest y Coordinate (Bounding Box, Contour Point Y).
x_lst: Last x-coordinate in the last line (Contour Point X).

The maximum and minimum values of x and y define the bounding box around the pixels chosen with color. rlc is the start address of the run length code in memory. f is a pointer to the feature list stored in the feature struct.

Memory Consumption: None.

See also: feature, rlc_area(), rl_ftr2().

◆ rl_ftr2()

I32 rl_ftr2	(	U16 *	src,
		ftr *	f,
		U32	n
	)

The function calculates object features of all objects in the labelled RLC. The following features are calculated:

area: Pixel Count.
x_center: x-Coordinate of the Center of Gravity.
y_center: y-Coordinate of the Center of Gravity.
x_min: Smallest x Coordinate (Bounding Box).
x_max: Largest x Coordinate (Bounding Box).
y_min: Smallest y Coordinate (Bounding Box).
y_max: Largest y Coordinate (Bounding Box, Contour Point Y).
x_lst: Last x-coordinate in the last line (Contour Point X).
x_lst: Last x-coordinate in the last line (Contour Point X).
color: Color (0=Black, 0xFFFF=White).

The maximum and minimum values of x and y define the bounding box around the chosen object. The object pixels are guaranteed to be contiguous. The coordinates (x_lst, y_max) specify a point which can serve as the initial value for contour following. Please make sure, that the connectedness of the object labelling (e.g. sgmt()) corresponds to the contour following algorithm. rlc is the start address of the labelled run length code in memory. f is a pointer to the feature list, ftr as struct array, n is the maximum number of objects, i.e. usually the dimension of the struct array. A pointer to the struct array is passed to this function. The pointer need not be initialized before you call this function. The struct array is provided with the correct features of all objects after the function is called.

The return value of the function is the number of objects in the labelled RLC.

See also: rl_area2(), rlc_feature().

Memory Consumption: None.

Return values

ERR_SLC	if RLC is Unlabelled.
ERR_RLC_ONOVR	if an Object Number Overrun occured.
Object Count	on Success.

◆ rl_ftr3()

I32 rl_ftr3	(	U16 *	src,
		ftr *	f,
		U32	n
	)

The function calculates object features of all objects in the labelled RLC. The following features are calculated:

area: Pixel Count.
x_center: x-Coordinate of the Center of Gravity.
y_center: y-Coordinate of the Center of Gravity.
x_cf: x-Coordinate of the Center of Gravity (Subpixel accurate).
y_cf: y-Coordinate of the Center of Gravity (Subpixel accurate).
x_min: Smallest x Coordinate (Bounding Box).
x_max: Largest x Coordinate (Bounding Box).
y_min: Smallest y Coordinate (Bounding Box).
y_max: Largest y Coordinate (Bounding Box, Contour Point Y).
x_lst: Last x-coordinate in the last line (Contour Point X).
color: Color (0=Black, 0xFFFF=White).

The maximum and minimum values of x and y define the bounding box around the chosen object. The object pixels are guaranteed to be contiguous. The coordinates (x_lst, y_max) specify a point which can serve as the initial value for contour following. Please make sure, that the connectedness of the object labelling (e.g. sgmt()) corresponds to the contour following algorithm.

In contrast to function rl_ftr2() which calculates the center of gravity only with pixel resolution, the function rl_ftr3() calculates it also in subpixel resolution and places the result in two additional variables in the data structure which are not used otherwise. rlc is the start address of the labelled run length code in memory. f is a pointer to the feature list (here: a struct array), n is the maximum number of objects, i.e. usually the dimension of the struct array. The struct used has the following structure:

typedef struct { 
   U32   area;     // object area                 
   U32   x_center; // x_center - normalized       
   U32   y_center; // y_center - normalized       
   I32   x_min;    // x_min                       
   I32   x_max;    // x_max                       
   I32   y_min;    // y_min                       
   I32   y_max;    // y_max                       
   I32   x_lst;    // last x                      
   I32   color;    // object color 0 = black      
   float x_cf;     // x_center, normalized, float 
   float y_cf;     // y_center, normalized, float 
} ftr;

A pointer to the struct array is passed to this function. The pointer need not be initialized before you call this function. The struct array is provided with the correct features of all objects after the function is called.

The function returns the standard error code or, if no error occurred, the number of objects in the labelled RLC.

Memory Consumption: None.

See also: rl_area2(), rlc_feature(), rl_ftr2().

Return values

ERR_SLC	if RLC is Unlabelled.
ERR_RLC_ONOVR	if Object Count exceeds `n`, or is Invalid.
Object Count	Count of Objects in the Labelled RLC.

◆ rlc_feret()

I32 rlc_feret	(	U16 *	src,
		float	alpha,
		float *	fer
	)

The function calculates the feret diameter for all objects and the projection of all objects with respect to angle alpha. The feret diameter is the size of the projection of the object into a certain angular direction, comparable to the measurement with a caliper held in that direction. For this purpose, the boundary of the object is projected into the direction alpha. The feret diameters of all objects is output as an array of float values.

The float array for the result (pointer fer) must have a size of at least nobj elements. (nobj = number of objects in RLC/SLC)

Parameters

src	Labelled Source RLC.
alpha	The projection angle in rad [0..PI].
fer	The result array pointer (size = nobj elements).

Memory Consumption: None.

See also: rlc_minmax_feret().

Return values

ERR_SLC	if RLC is unlabelled.
ERR_RLC_ONOVR	if SLC object count is inappropriate.
ERR_MEMORY	if internal feret list cannot be allocated.
ERR_NONE	on success.

◆ rlc_minmax_feret()

I32 rlc_minmax_feret	(	U16 *	pRlc,
		I32	nsteps,
		float	fMinAngleRad,
		float	fMaxAngleRad,
		float *	minferets,
		float *	minangles,
		float *	maxferets,
		float *	maxangles
	)

The function calculates the feret diameter for all objects. The feret diameter is the size of the projection of the object into a certain angular direction, comparable to the measurement with a caliper held in that direction. For this purpose, the boundary of the object is projected into the direction of nsteps angles in the range of [fMinAngleRad .. fMaxAngleRad). The feret diameters of all objects are output as arrays of float values.

Unlike the function rlc_feret(), the function rlc_minmax_feret() calculates the minimum and maximum feret diameters for all objects. This is done by calling the function rlc_feret() nsteps times and sweeping the projection angle starting at angle = fMinAngleRad incresing angle from step to step by delta = (fMaxAngleRad - fMinAngleRad)/nsteps.

In addition to the minimum and maximum diameters, the angles where the maximum and minimum were detected are also provided for earch object.

The float arrays for the result ferets and angles must have a size of at least nobj elements each. (nobj = number of objects in RLC/SLC)

All angles are in rad.

Parameters

pRlc	Labelled Source RLC.
nsteps	number of steps for feret calculation (angular resolution)
fMinAngleRad	the minimum angle for the interation [rad].
fMaxAngleRad	the maximum angle for the interation [rad].
minferets	result array pointer for minimum feret or NULL.
minangles	result array pointer for minimum angle or NULL.
maxferets	result array pointer for maximum feret or NULL.
maxangles	result array pointer for maximum angle or NULL.

Memory Consumption: None.

See also: rlc_feret().

Return values

ERR_SLC	for unlabelled RLC.
ERR_SLC_INCON	if SLC object count is inappropriate.
ERR_PARAM	for fMinAngleRad >= fMaxAngleRad.
ERR_PARAM	for fMinAngleRad < -PI.
ERR_PARAM	for fMinAngleRad >= 2*PI.
ERR_MEMORY	if out ou memory.

RLC Features

Modules

Functions

Detailed Description

Function Documentation

◆ rlc_feature()

◆ rl_ftr2()

◆ rl_ftr3()

◆ rlc_feret()

◆ rlc_minmax_feret()