FingerprintImage Class Reference

Description

Class encapsulating fingerprint image data plus associated metadata.

This structure is used by FingerprintListener to deliver the results of successful fingerprint image captures to the user.

Thread safety:

• Static functions: safe
• Concurrent accesses to distinct objects: safe
• Concurrent accesses to same object: unsafe, unless all accesses are read-only (i.e. query functions, generateBase64(), generateBitmap())

Classes
enum	TypeID
	Enumeration of fingerprint image types for capture and enrolment functions. More...

Public Member Functions
	FingerprintImage ()
	Default construction - null (empty) image.
	FingerprintImage (@NonNull byte[] initData, @NonNull TypeID initType, int initRows, int initColumns)
	Construction with given image data and metadata. More...
int	columns ()
	Query the number of pixel columns in the image. More...
byte []	data ()
	Query the contents of the fingerprint image. More...
String	generateBase64 (@NonNull ErrorCode error)
	Encode a fingerprint image as a MIME-compliant Base64 string. More...
byte []	generateBitmap (@NonNull ErrorCode error)
	Attempt to generate a grey-scale bitmap (BMP/DIB format) from the image. More...
TypeID	imageType ()
	Query the type of image data represented by the object. More...
int	rows ()
	Query the number of pixel rows in the image. More...
void	setColumns (int newColumns)
	Set the number of pixel columns in the image. More...
void	setData (@NonNull byte[] newData)
	Set the contents of the fingerprint image. More...
void	setImageType (@NonNull TypeID newType)
	Set the type of image data represented by the object. More...
void	setRows (int newRows)
	Set the number of pixel rows in the image. More...
String	typeName ()
	Obtain the name of the current image type ID. More...

Static Public Member Functions
static String	typeName (@NonNull TypeID imageType)
	Obtain the name of a given image type ID. More...

Constructor & Destructor Documentation

FingerprintImage()

FingerprintImage	(	@NonNull byte []	initData,
		@NonNull TypeID	initType,
		int	initRows,
		int	initColumns
	)

Construction with given image data and metadata.

Parameters

initData	Initial value of the image data, passed by copy
initType	Initial value of the image type ID
initRows	Initial count of pixel rows in the image; must be non-negative
initColumns	Initial count of pixel columns in the image; must be non-negative

Exceptions

IllegalArgumentException

if any of the supplied parameters are invalid

Member Function Documentation

columns()

int columns

(

)

Query the number of pixel columns in the image.

Returns

Number of pixel columns

data()

byte [] data

(

)

Query the contents of the fingerprint image.

For uncompressed images this will use a raw 8bpp grayscale format - i.e. one byte per pixel, scanning left to right within each row, and rows ordered from top to bottom. No header or footer data is included.

For images in the V1 or WSQ formats, the specified data format is used; refer to the relevant format specifications for additional details.

Returns

Image contents, represented in the specified format and passed by copy

generateBase64()

String generateBase64

(

@NonNull ErrorCode

error

)

Encode a fingerprint image as a MIME-compliant Base64 string.

If the supplied error code indicates no prior errors, and the image is not in the V1 compression format, then an attempt will be made to convert the fingerprint image to the BMP (DIB) format as per generateBitmap(). The resultant image data is then encoded as a Base64 string, with a suitable MIME type header prepended.

Parameters

error

Error code; operation proceeds only if set to NO_ERROR. If an error is detected during this operation, then the parameter will be updated with the details.

Returns

Generated encoding if the operation proceeds and is successful; empty string otherwise

generateBitmap()

byte [] generateBitmap

(

@NonNull ErrorCode

error

)

Attempt to generate a grey-scale bitmap (BMP/DIB format) from the image.

If the supplied error code indicates no prior errors, and the image is not in the V1_COMPRESSION format, then an attempt will be made to convert that image to the Microsoft BMP (DIB) format.

Image data for this function is typically taken from a FingerprintListener.imageEvent callback parameter.

Note

This decoder has not been FBI-certified, and is not guaranteed to be accurate for the purposes of automatic fingerprint comparison.

Parameters

error

Error code; operation proceeds only if set to NO_ERROR. If an error is detected during this operation, then the parameter will be updated with the details.

Returns

Generated bitmap file if the operation proceeds and is successful, empty (0x0) bitmap otherwise

imageType()

TypeID imageType

(

)

Query the type of image data represented by the object.

Returns

Image type; see TypeID for details

rows()

int rows

(

)

Query the number of pixel rows in the image.

Returns

Number of pixel rows

setColumns()

void setColumns

(

int

newColumns

)

Set the number of pixel columns in the image.

Parameters

newColumns

New number of pixel columns

setData()

void setData

(

@NonNull byte []

newData

)

Set the contents of the fingerprint image.

Refer to data() for the details of the format.

Parameters

newData

Image contents, represented in the specified format

setImageType()

void setImageType

(

@NonNull TypeID

newType

)

Set the type of image data represented by the object.

Parameters

newType

New image type in the TypeID format

setRows()

void setRows

(

int

newRows

)

Set the number of pixel rows in the image.

Parameters

newRows

New number of pixel rows

typeName() [1/2]

String typeName

(

)

Obtain the name of the current image type ID.

Returns

String representation of imageType() if known; empty string if unknown

typeName() [2/2]

static String typeName ( @NonNull TypeID  imageType )

static

Obtain the name of a given image type ID.

Parameters

imageType

The type of image which is being queried

Returns

String representation of supplied image type if known; empty string if unknown