ILBlob Interface Reference

This interface holds single blob and provide functionalities of blob calculation, conversion and drawing. More...

Inheritance diagram for ILBlob:

Public Member Functions
void	AttachImage (ILImage *image)
int	CountContour ()
int	CountHole ()
void	Draw (HDC hdc, LPVBlobDrawFlags drawFlags, double zoomX, double zoomY, double panX, double panY)
void	FromRegion (ILRegion *region, ILImage *image)
double	GetAngle (BOOL alwaysUp)
ILPoint *	GetCenter ()
ILPolygon *	GetContour (int index)
double	GetContrast (LPVAggregation aggType, double percentage)
ILPolygon *	GetConvexHull ()
double	GetFeature (LPVBlobFeatures feature)
ILPolygon *	GetHole (int index)
double	GetLuminance (LPVAggregation aggType, double percentage)
ILRect *	GetRect ()
ILRect *	GetRotRect ()
ILMaskRegion *	ToRegion ()
Public Member Functions inherited from ILObject
ILObject *	Copy ()
LPVErrorCode	Load (LString filename)
void	Reset ()
LPVErrorCode	Save (LString filename)
BOOL	Valid ()

Detailed Description

This interface holds single blob and provide functionalities of blob calculation, conversion and drawing.

Usually you get the LBlob object from the ILBlobResults::Item() function. You can then use this interface to calculate the interested features, access to the detailed blob informations and draw the result on graphics windows.

Example Code

C++

ILBlobPtr blob = blobResults->Item(i);
double area = blob->GetFeature(LPVBlobFeatures::LPVBlobArea));

C#

LBlob blob = blobResults.Item(i);
double area = blob.GetFeature(LPVBlobFeatures.LPVBlobArea));

COM

ILBlobPtr blob = blobResults->Item(i);
double area = blob->GetFeature(LPVBlobFeatures::LPVBlobArea));

Member Function Documentation

AttachImage()

void AttachImage

(

ILImage *

image

)

Attach the input image to the blob, used for image-related feature calculation, such as luminance, contrast, sharpness, etc..

Parameters

[in]

image

The input image

CountContour()

int CountContour

(

)

Get count of the external contours of the blob

See also

GetContour(), CountHole()

CountHole()

int CountHole

(

)

Get count of the external contours of the blob

See also

GetHole(), CountContour()

Draw()

void Draw	(	HDC	hdc,
		LPVBlobDrawFlags	drawFlags,
		double	zoomX,
		double	zoomY,
		double	panX,
		double	panY
	)

Draw the blob onto provide device context.

Parameters

[in]

drawFlags

Flags to control the blob drawing behavior, see LPVBlobDrawFlags for usage.

See also

Use Draw Functions

Remarks

This function is currently not available on Linux / MacOS platform.

FromRegion()

void FromRegion	(	ILRegion *	region,
		ILImage *	image
	)

Construct the blob object from a region object.

Parameters

[in]	region	The input region object.
[in]	image	The input image to be attached to the blob. It is used for image-related feature calculation, such as luminance, contrast, sharpness, etc.. Pass in null if you don't want do that.

GetAngle()

double GetAngle

(

BOOL

alwaysUp

)

Get the angle of the blob. It's the same direction as the blob's rotate bounding rectangle's longer axis, in range of (-90, 90).

Parameters

[in]

alwaysUp

If it's on, return the angle of the up axis, it could either the longer axis or the shorter axis. It is useful when the difference between axes is not notable, for example, it's a square object, but the rotation is slight. An always-up angle is in range of (-135, -45).

Return values

val	Return the angle

GetCenter()

ILPoint* GetCenter

(

)

Get the center of gravity of the blob.

GetContour()

ILPolygon* GetContour

(

int

index

)

Fetch one external contour of the blob with given index.

Parameters

[in]

index

The input index, it should be a 0-based number smaller than total count.

Return values

val	Return the external contour as polygon

See also

CountContour(), GetHole()

GetContrast()

double GetContrast	(	LPVAggregation	aggType,
		double	percentage
	)

Calculate the aggregated contrast feature of the blob, only available when an image is attached to the blob.

Parameters

[in]	aggType	Aggregation type, see LPVAggregation for usage.
[in]	percentage	Specify the top/bottom percentage of pixels used in aggregation. A positive value indicates the top X% pixels sorted by their contrast value descendingly, a negative value use the bottom X%. Pass in 0 to use all pixels.

Return values

val	Return the aggregated contrast feature result.

GetConvexHull()

ILPolygon* GetConvexHull

(

)

Get the bounding convex hull of the blob

See also

GetRect(), GetRotRect().

GetFeature()

double GetFeature

(

LPVBlobFeatures

feature

)

Calculate the specified numeric feature of the blob.

Parameters

[in]

feature

Specify the required feature, see LPVBlobFeatures.

Return values

val	Return the feature result.

GetHole()

ILPolygon* GetHole

(

int

index

)

Fetch one hole of the blob with given index.

Parameters

[in]

index

The input index, it should be a 0-based number smaller than total count.

Return values

val	Return the hole contour as polygon

See also

CountHole(), GetContour()

GetLuminance()

double GetLuminance	(	LPVAggregation	aggType,
		double	percentage
	)

Calculate the aggregated luminance feature of the blob, only available when an image is attached to the blob.

Parameters

[in]	aggType	Aggregation type, see LPVAggregation for usage.
[in]	percentage	Specify the top/bottom percentage of pixels used in aggregation. A positive value indicates the top X% pixels sorted by their luminance value descendingly, a negative value use the bottom X%. Pass in 0 to use all pixels.

Return values

val	Return the aggregated luminance feature result.

GetRect()

ILRect* GetRect

(

)

Get the bounding rectangle of the blob

See also

GetRotRect(), GetConvexHull().

GetRotRect()

ILRect* GetRotRect

(

)

Get the rotated bounding rectangle of the blob

See also

GetRect(), GetConvexHull().

ToRegion()

ILMaskRegion* ToRegion

(

)

Convert the blob object to a mask region object.

Return values

region

Return the result region object.