Documentation Index
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Overview
The NFIQ2::FingerprintImageData class represents binary data for a decompressed fingerprint image, canonically encoded as per ISO/IEC 39794-4:2019. This class inherits from NFIQ2::Data and adds fingerprint-specific metadata.
Class Definition
namespace NFIQ2 {
class FingerprintImageData : public Data {
// Public interface
};
}
Constants
Resolution500PPI
static const uint16_t Resolution500PPI { 500 };
Constructors
Default Constructor
Default constructor.
FingerprintImageData(
uint32_t width,
uint32_t height,
uint8_t fingerCode,
uint16_t ppi);
Width of the image in pixels.
Height of the image in pixels.
Finger position of the fingerprint in the image.
Resolution of the image in pixels per inch.
Full Constructor
FingerprintImageData(
const uint8_t *pData,
uint32_t dataSize,
uint32_t width,
uint32_t height,
uint8_t fingerCode,
uint16_t ppi);
Pointer to decompressed 8 bit-per-pixel grayscale image data, canonically encoded as per ISO/IEC 39794-4:2019.
Size of the buffer pointed to by pData.
Width of the image in pixels.
Height of the image in pixels.
Finger position of the fingerprint in the image.
Resolution of the image in pixels per inch.
Copy Constructor
FingerprintImageData(const FingerprintImageData &otherData);
Public Members
width
Width of the fingerprint image in pixels.
height
Height of the fingerprint image in pixels.
fingerCode
uint8_t fingerCode { 0 };
ppi
uint16_t ppi { Resolution500PPI };
Methods
copyRemovingNearWhiteFrame
NFIQ2::FingerprintImageData copyRemovingNearWhiteFrame() const;
return
NFIQ2::FingerprintImageData
Cropped fingerprint image.
NFIQ2::Exception if error performing the crop, or the image is too small to be processed after cropping.
Inherited Methods from Data
Since FingerprintImageData inherits from NFIQ2::Data, the following methods are also available:
readFromFile
void readFromFile(const std::string &filename);
NFIQ2::Exception if file cannot be opened.
writeToFile
void writeToFile(const std::string &filename) const;
NFIQ2::Exception if file cannot be opened.
toHexString
std::string toHexString() const;
NFIQ2::Exception if no data available in buffer.
fromBase64String
void fromBase64String(const std::string &base64String);
NFIQ2::Exception if invalid character is detected in string.
toBase64String
std::string toBase64String() const;
Usage Example
#include <nfiq2_fingerprintimagedata.hpp>
// Create fingerprint image data from raw pixels
uint8_t* pixels = /* ... load image data ... */;
uint32_t width = 640;
uint32_t height = 480;
uint8_t fingerCode = 1; // Right thumb
uint16_t ppi = NFIQ2::FingerprintImageData::Resolution500PPI;
NFIQ2::FingerprintImageData imageData(
pixels,
width * height,
width,
height,
fingerCode,
ppi
);
// Remove near-white borders
NFIQ2::FingerprintImageData cropped = imageData.copyRemovingNearWhiteFrame();
The fingerprint image must be:
- 8 bit-per-pixel grayscale
- Decompressed (raw pixels)
- Canonically encoded as per ISO/IEC 39794-4:2019
See Also
- Algorithm - Uses FingerprintImageData for quality scoring
- Data - Base class for binary data handling
