ILPathDetector Interface Reference

This interface provide functionalities of path detection. More...

Inheritance diagram for ILPathDetector:

Public Member Functions
LPVErrorCode	Detect (ILImage *img, ILRotRectRegion *region, ILPathResults **results)
Public Member Functions inherited from ILObject
ILObject *	Copy ()
LPVErrorCode	Load (LString filename)
void	Reset ()
LPVErrorCode	Save (LString filename)
BOOL	Valid ()

Properties
int	AcceptRelativeScore [get, set]
	The relative accept score used in detection, which is useful for noise removal. The relative score is computed using the current and the next result candidate or background pixels as \( Abs(e - e') / Max(e, e') * 100% \). If the relative score is bigger than the threshold, than the candidate is accepted as the report result. It's in 0 ~ 100, by default set to 20. The smaller relative score indicates more sensitive detection and more path outputs. For low contrast between the path and the background, a larger relative score is preferred. Set to 0 to disable the relative threshold. If both the accept and relative score is defined, the result should meet either of the criteria.
int	AcceptScore [get, set]
	The accept score used in detection. It defines the minimum(LPVWhiteOnBlack ) or maximum(LPVBlackOnWhite ) score for identifying the result as a good path. It's in 0 ~ 255, by default, it's set to 0 which in fact does not work. .
int	MaxCount [get, set]
	The maximum of paths to find.
int	PathWidth [get, set]
	The width of the path used in detection. If two paths are closer than the width, they are treat as one and then merged. It's in 1 ~ 100, by default, it's set to 10 pix.
LPVPolarity	Polarity [get, set]
	The detection object polarity. It should be either LPVBlackOnWhite (the black path on the white background) or LPVWhiteOnBlack (the white path on the black background)
int	Straightness [get, set]
	The straightness controls the trend of the path. It's in 0 ~ 100, where 100 means a totally straight line, 0(default) means no punishment for steering.

Detailed Description

This interface provide functionalities of path detection.

Path detector is designed to locate a single or multiple paths in given image and along the region's direction.
The algorithm searches the input image for the darkest(LPVBlackOnWhite ) or brightest(LPVWhiteOnBlack ) vertical paths. The paths grow towards the minimum/maximum overall energy, they are in most case straight, but steer to get around the obstacles(other foreground objects or noise).

To use this interface, you should create a LPathDetector object.

Example Code

C++

ILPathDetectorPtr pathDetector = LPathDetector::Create();
pathDetector->Polarity = LPVPolarity::LPVBlackOnWhite;
LPVErrorCode err = pathDetector->Detect(img, rotRectRoi, &pathResults);
if (err != LPVErrorCode::LPVNoError) return;

C#

LPathDetector pathDetector = new LPathDetector();
pathDetector.Polarity = LPVPolarity.LPVBlackOnWhite;
LPVErrorCode err = pathDetector.Detect(img, rotRectRoi, out pathResults);
if (err != LPVErrorCode.LPVNoError) return;

COM

ILPathDetectorPtr pathDetector = LPathDetector::Create();
// or, ILPathDetectorPtr pathDetector(__uuidof(LPathDetector)), for absence of built-in Create functions (before 2.2.0)
pathDetector->Polarity = LPVPolarity::LPVBlackOnWhite;
LPVErrorCode err = pathDetector->Detect(img, rotRectRoi, &pathResults);
if (err != LPVErrorCode::LPVNoError) return;

Member Function Documentation

Detect()

LPVErrorCode Detect	(	ILImage *	img,
		ILRotRectRegion *	region,
		ILPathResults **	results
	)

Detect paths using the path detector.

Parameters

[in]	img	The input image.
[in]	region	The input region, it should be a rotated rectangle region with its direction well-defined.
[out]	results	Return the path results.

Return values

error

Return error code if anything is wrong.