A basic task in image processing, known as "connected components extraction", consists in managing and sorting blobs defined by a series of filters. The tlBlobs object is a collection of tlMask objects that does just that. Given a binary image, it segments, extracts and labels sets of connected pixels into tlMask objects, that can then be sorted with respect to different criterions. This is extremely useful for object extraction.


Public Member Functions
	tlBlobs ()
	tlBlobs (tlImage *image, int minArea=0)
	tlBlobs (tlImage image, tlRect rect, int minArea=0)
virtual	~tlBlobs ()
int	getCount ()
tlMask *	getBlob (int index)
int	getBlob (int index, tlMask *mask)
tlMask *	getBlobCopy (int index)
int	reset ()
int	clear ()
int	extract (tlImage *image, int minArea=0)
int	extract (tlImage image, tlRect rect, int minArea=0)
int	filterArea (int minArea, int maxArea)
int	filterMinArea (int minArea)
int	filterMaxArea (int maxArea)
int	sortByArea ()
int	add (tlMask *mask)
int	insert (int index, tlMask *mask)
int	remove (int index)
int	swap (int index1, int index2)

Constructor & Destructor Documentation

tlBlobs::tlBlobs ( )

Constructor, creates an empty tlBlobs object. Call extract(tlImage *image, int minArea) to perform the extraction.

Note:: See error management for details.

tlBlobs::tlBlobs	(	tlImage *	image,
		int	minArea = `0`
	)

Constructor, creates a tlBlobs object from an initial binary image.

Parameters:

	image	binary image for blob extraction.
	minArea	minimal area a blob must have to be considered; smaller blobs are ignored.

Note:: See error management for details.

tlBlobs::tlBlobs	(	tlImage *	image,
		tlRect *	rect,
		int	minArea = `0`
	)

Constructor, creates a tlBlobs object from a portion of a binary image.

Parameters:

	image	binary image for blob extraction.
	rect	portion of the image to process.
	minArea	minimal area a blob must have to be considered; smaller blobs are ignored.

Note:: See error management for details.

tlBlobs::~tlBlobs ( ) [virtual]

Destructor.

Note:: See error management for details.

Todo:: fix blobs destructor crash

Member Function Documentation

int tlBlobs::getCount ( ) [inline]

Get the number of blobs currently in the list.

Returns:: the blob count.

tlMask * tlBlobs::getBlob ( int index )

Get the blob at a given index in the chain (if it exists).

Parameters:

index

point index

Returns:: A pointer to the existing tlMask * success, NULL otherwise. See error management for details.

Remarks:: the pointer returned points to the actual mask in the chained list. Thus, it should NOT be deleted. Use getBlobCopy() to get a copy of the blob.

int tlBlobs::getBlob	(	int	index,
		tlMask *	mask
	)

Fill an existing blob with data from the blob at a given index in the chain (if it exists).

Parameters:

	index	point index
	mask	mask to fill

Returns:: 0 on success, -1 otherwise.
See error management for details.

See also:: getBlob (int index) getBlobCopy (int index)

tlMask * tlBlobs::getBlobCopy ( int index )

Get a copy of the blob at a given index in the chain (if it exists).

Parameters:

index

point index

Returns:: A pointer to a copy of the existing tlMask on success, NULL otherwise. See error management for details.

Remarks:: the pointer returned points to a new mask. Thus, it should be deleted after use. Use getBlobCopy() to get a pointer to the actual blob.

int tlBlobs::reset ( )

Reset the blob list (remove all blobs).
Same as clear().

Returns:: 0 on success, -1 otherwise.
See error management for details.

int tlBlobs::clear ( )

Reset the blob list (remove all blobs).
Same as reset().

Returns:: 0 on success, -1 otherwise.
See error management for details.

int tlBlobs::extract	(	tlImage *	image,
		int	minArea = `0`
	)

Perform a blob extraction on the given image. This routine ignores all blobs whose area is smaller than minArea.

Parameters:

	image	binary image to perform extraction from
	minArea	minimal blob area [pix]

Returns:: The number of blobs found on success.
On error, -1 is returned and tl_errno is set.
See TL_ERROR for details.

int tlBlobs::extract	(	tlImage *	image,
		tlRect *	rect,
		int	minArea = `0`
	)

Perform a blob extraction on a portion of the given image. This routine ignores all blobs whose area is smaller than minArea.

Parameters:

	image	binary image to perform extraction from
	minArea	minimal blob area [pix]
	rect	portion of the image to process

Returns:: The number of blobs found on success, -1 otherwise.
See error management for details.

int tlBlobs::filterArea	(	int	minArea,
		int	maxArea
	)

Filters the blobs according to their apparent area and deletes blob which do not satisfy the criterias

Parameters:

	minArea	minimal blob area [pix]
	maxArea	maximal blob area [pix]

Returns:: 0 on success, -1 otherwise.
See error management for details.

int tlBlobs::filterMinArea ( int minArea )

Filters the blobs according to their apparent area and deletes blob which do not satisfy the criterias

Parameters:

minArea

minimal blob area [pix]

Returns:: 0 on success, -1 otherwise.
See error management for details.

int tlBlobs::filterMaxArea ( int maxArea )

Filters the blobs according to their apparent area and deletes blob which do not satisfy the criterias

Parameters:

maxArea

maximal blob area [pix]

Returns:: 0 on success, -1 otherwise.
See error management for details.

int tlBlobs::sortByArea ( )

Sort the blobs by area so that the biggest blob is at index 0.

Returns:: 0 on success, -1 otherwise.
See error management for details.

int tlBlobs::add ( tlMask * mask )

Insert a blob at the end of the list.

Parameters:

mask

the blob to add

Returns:: The index of the point if insertion on success, -1 otherwise.
See error management for details.

int tlBlobs::insert	(	int	index,
		tlMask *	mask
	)

Insert a blob at a specific index in the chained list.

Parameters:

	index	the index to insert to blob at
	mask	the blob to insert

Returns:: 0 on success, -1 otherwise.
See error management for details.

int tlBlobs::remove ( int index )

Remove a blob at a specific index from the chained list.

Parameters:

index

the index of the blob to remove

Returns:: 0 on success, -1 otherwise.
See error management for details.

int tlBlobs::swap	(	int	index1,
		int	index2
	)

Swap two blobs within the list.

Parameters:

	index1	the first blob
	index2	the second blob

Returns:: 0 on success, -1 otherwise.
See error management for details.

tlBlobs Class Reference

Detailed Description

Public Member Functions

Constructor & Destructor Documentation

Member Function Documentation