High performance and reliable barcode decoding. It reads torn, crumpled barcodes and also barcodes corrupted in other ways. Decodes barcodes printed on various surfaces - plastic surfaces, distorted surfaces, etc.

Can search only part of image for barcodes.

Reads all barcodes from an image at a once independently of the orientation and location of the barcode.

Does not require the barcode to have a quiet zone. That is why it can read incorrectly positioned barcodes.

Can read barcodes from noisy and blurred images.

It can find barcodes that cannot be recognized.

Decodes images that have distortions typical of scanned images and images received by fax.

Processes low resolution and dithering images.

Decodes barcodes with human-introduced artifacts (signatures, marks, etc.).

Requirements

The DataSymbol SDK library has the following system requirements:

· Linux/MacOS

Installation

Copy the SDK in any folder of your machine.

Directory Structure

DataSymbol SDK is a dynamic library written on С++. You should to copy libdsdecoder.so.1 (libdsdecoder.dylib.1) into the folder /lib, /usr/lib or any other (if your project has settings to get library from this path).

The DataSymbol SDK contains the following directories and files:

/lib	libdsdecoder.so.1 (libdsdecoder.dylib.1)
/test	C++ example

Technical Specifications

Decodes all popular barcode types.

Linear:

Interleaved 2/5, Industrial 2/5, Code 39, Code 39 Extended, Codabar, Code 11, Code 128, Code 128 Extended, EAN/UCC 128, UPC-E, UPC-A, EAN-8, EAN-13, Code 93, Code 93 Extended, DataBar Omnidirectional (RSS-14), DataBar Truncated (RSS-14 Truncated), DataBar Limited (RSS Limited), DataBar Stacked, DataBar Expanded, DataBar Expanded Stacked.

2D: PDF417 (PDF417 Compact), QRCode, DataMatrix, Aztec (Aztec Compact)

Decodes any oriented barcodes.

Decoding time: depends from many factors (library settings, image size, barcode count, etc.) but usually up to 50ms on 2 GHz machine on 840x480 image.

Approximately barcode resolution (minimal module size) in pixel

Linear: 0.7 px

PDF417: 1.3 px

DataMatrix: 2 px

QRCode: 1.6 px

AztecCode: 1.6 px

Getting Started

The usage of the library is very simple. Here below, please, find the typical sample of the library usage.

#include "DecoderWrap.h"

…

//create decoder

CDecoderWrap dec;

dec.InitLib(0);

//set decoder parameters

DW_DECODEPARAMS decParams;

decParams.barcodeTypes |= DW_ST_QRCODE|DW_ST_PDF417|DW_ST_AZTECCODE;

dec.SetDecoderParams( decParams );

int res = dec.Decode( buf, width, height, 0 );

if( res != DW_OK )

return;

int num=0;

res = dec.getResNum( &num );

printf( "Decoded: %d\n", num );

for( int i=0; i < num; ++i )

{

const char* pszStr;

unsigned int barType;

res = dec.getResHymanData( &pszStr, i );

res = dec.getResBarcodeType( &barType, i );

printf( "Barcode %d: %s\n", num, pszStr );

}

CDecoderWrap methods

InitLib

Initializes library. You need to call this method before any else.

Syntax

int InitLib(const char* pszKey);

Parameters

pszKey

Library key.

Return Value

Error code. DW_OK if no errors.

Decode

Decodes one frame. The frame is a byte matrix. Each byte has the value from 0 to 255 and represents one image pixel. 0 means a black pixel, 255 means a white pixel. Pixels are placed from the left to the right, from top to bottom, row by row.

The matrix is passed to the Decode method as a one-dimensional array. The first upper line of the image is sent first, then comes the second line and so on.

See the picture below for explanation.

Syntax

int Decode(unsigned char* pImg, int width, int height,

const DW_RECT* pRect);

Parameters

pImg	pointer to the frame array
width	frame width
height	frame height
pRect	scanning zone rectangle, if null scan whole frame

Return Value

Error code. DW_OK if no errors.

Decode

Decodes .pgm file.

Syntax

int Decode(void* pPGM, unsigned int pgmLen, const DW_RECT* pRect);

Parameters

pPgm	pointer to the .pgm file in memory
pgmLen	.pgm file length
pRect	scanning zone rectangle, if null scan whole frame

Return Value

Error code. DW_OK if no errors.

SetDecoderParams

Sets all decoder properties.

Syntax

int SetDecoderParams(const DW_DECODEPARAMS& decParams);

Parameters

decParams

DW_DECODEPARAMS structure

Return Value

Error code. DW_OK if no errors.

getResNum

Returns the quantity of barcodes which were found.

Syntax

int getResNum(int* pNum) const;

Parameters

pNum	Gets the quantityt of barcodes which were found

Return Value

Error code. DW_OK if no errors.

getResBarcodeType

Returns barcode type.

Syntax

int getResBarcodeType(unsigned int* pType, int resNum) const;

Parameters

pType

Returns barcode type

resNum

Number of the barcode you want to get. The following condition should be fulfilled:

resNum >= 0 && resNum < num (returned by getResNum)

Return Value

Error code. DW_OK if no errors.

getResHymanData

Returns human readable data (barcode string).

Syntax

int getResHymanData(const char** ppszStr, int resNum) const;

Parameters

ppszStr	Returns pointer to the zero terminated string.
resNum	Number of the barcode you want to get.

Return Value

Error code. DW_OK if no errors.

Example

const char* pszStr;

res = dec.getResHymanData( &pszStr, i );

printf( pszStr );

getResData

Returns raw barcode data. Some barcode types (PDF417, Code128, QRCode, etc.) can contain binary data, that is why to get this barcode you should better use this method instead of getResHymanData.

Syntax

int getResData(const unsigned char** ppData, int* pDataLen, int resNum);

Parameters

ppData	Returns pointer to the raw barcode data.
pDataLen	Data length.
resNum	Number of the barcode you want to get.

Return Value

Error code. DW_OK if no errors.

Example

const unsigned char* pData;

int dataLen;

res = dec.getResData( &pData, &dataLen, 0 );

for( int j=0; j < dataLen; ++j )

printf( "%d ", pData[j] );

getResDQ

Returns barcode decoding reliability (decoding quality). Possible values 0…100. Decoding quality less than 30 is considered as bad. This parameter is actual for 2D barcodes (PDF417, DataMatrix, QRCode, Aztec).

Syntax

int getResDQ(unsigned char* pDQ, int resNum) const;

Parameters

pDQ	Decoding Quality
resNum	Number of the barcode you want to get.

Return Value

Error code. DW_OK if no errors.

getResPoints

Returns barcode coordinates.

Syntax

int getResPoints(const DW_POINT** ppt, int resNum) const;

Parameters

ppt	Pointer to the array with four DW_POINT structure
resNum	Number of the barcode you want to get.

Return Value

Error code. DW_OK if no errors.

Example

const DW_POINT* pt;

res = dec.getResPoints( &pt, 0 );

printf( "(%d,%d), (%d,%d), (%d,%d), (%d,%d)\n", pt[0].x, pt[0].y, pt[1].x, pt[1].y, pt[2].x, pt[2].y, pt[3].x, pt[3].y );

Other Types

DW_DECODEPARAMS structure

Sets all decoder properties.

General
barcodeTypes	Sets what types of barcodes should be decoded. Each barcode type has specified integer value. The BarcodeTypes property can consist of any combination of these values, you should use the OR for that. Example: barcodeTypes = DW_ST_PDF417\|DW_ST_QRCODE;
inverseType	Sets what barcodes should be decoded (darks on light or lights on dark).
Linear
bLinearShowSymbologyID	Sets the value determining whether to add Symbology ID to the barcode text or not.
uiLinearFindBarcodes	Sets how many Linear barcodes should be decoded on the image. An image may contain one or several barcodes. Works only in Professional edition, Standard decodes only one barcode.
bLinearVerifyCheckDigit	Sets the value determining whether to verify the optional check digit in barcodes where this check digit is optional.
bLinearShowCheckDigit	Show the check digit or not.
bLinearShowStartStop	Show the start/stop characters or not. Some barcode types have start/stop characters (for example, Code39).
bLinearCode39EnableExtended	Decode Code 39 as Code 39 Extended or not.
bLinearUPCE2UPCA	Convert a UPC-E barcode to UPC-A or not.
uiLinearInterl25MinLen	The minimum length of an Interleaved 2/5 barcode. If the length of a read barcode is less than this value, the barcode is considered unrecognized.
uiLinearInterl25MaxLen	The maximum length of an Interleaved 2/5 barcode.
uiLinearIndustr25MinLen	The minimum length of an Industrial 2/5 barcode.
uiLinearIndustr25MaxLen	The maximum length of an Industrial 2/5 barcode.
uiLinearCode11MinLen	The minimum length of a Code11 barcode.
uiLinearCode11MaxLen	The maximum length of a Code11 barcode.
uiLinearCode39MinLen	The minimum length of a Code39 barcode.
uiLinearCode39MaxLen	The maximum length of a Code39 barcode.
uiLinearCode128MinLen	The minimum length of a Code128 barcode.
uiLinearCode128MaxLen	The maximum length of a Code128 barcode.
uiLinearCodabarMinLen	The minimum length of a Codabar barcode.
uiLinearCodabarMaxLen	The maximum length of a Codabar barcode.
uiLinearCode93MinLen	The minimum length of a Code93 barcode.
uiLinearCode93MaxLen	The maximum length of a Code93 barcode.
LinearDecSpeed	Linear barcode reading speed. Possible values: · 0 - Normal · 1 - Fast · 2 - Slow
bLinearVerify	Verify linear barcode after decoding. Improves reliability linear barcode reading.
PDF417
uiPDF417FindBarcodes	Sets how many PDF417 barcodes should be decoded on the image.
PDF417DecSpeed	PDF417 barcode reading speed.
bPDF417SymbologyID	Add Symbology ID to the barcode text or not.
DataMatrix
uiDataMatrixFindBarcodes	Sets how many DataMatrix barcodes should be decoded on the image.
DataMatrixDecSpeed	DataMatrix barcode reading speed.
bDataMatrixSymbologyID	Add Symbology ID to the barcode text or not.
DataMatrixInverseType	What barcodes should be decoded (darks on light or lights on dark).
bDataMatrixSupportECI	Support or not ECI (Extended Channel Interpretation).
QRCode
uiQRCodeFindBarcodes	Sets how many QRCode barcodes should be decoded on the image.
QRCodeDecSpeed	QRCode barcode reading speed.
bQRCodeSymbologyID	Add Symbology ID to the barcode text or not.
bQRCodeFindMicro	Finds Micro QRCode barcodes.
AztecCode
uiAztecCodeFindBarcodes	Sets how many AztecCode barcodes should be decoded on the image.
AztecCodeDecSpeed	AztecCode barcode reading speed.
bAztecCodeSymbologyID	Add Symbology ID to the barcode text or not.

Barcode Types

Barcode Type	Value	Constant
Code 128	0x00000001	DW_ST_CODE128
Code 39	0x00000002	DW_ST_CODE39
Interleaved 2/5	0x00000004	DW_ST_INTERL25
EAN-13	0x00000008	DW_ST_EAN13
EAN-8	0x00000010	DW_ST_EAN8
Codabar	0x00000020	DW_ST_CODABAR
Code 11	0x00000040	DW_ST_CODE11
UPC-A	0x00000080	DW_ST_UPCA
UPC-E	0x00000100	DW_ST_UPCE
Industrial 2/5	0x00000200	DW_ST_INDUSTR25
Code 93	0x00000400	DW_ST_CODE93
DataBar omnidirectional, DataBar Truncated	0x00000800	DW_ST_DATABAR_OMNI
DataBar limited	0x00001000	DW_ST_DATABAR_LIM
DataBar stacked	0x00002000	DW_ST_DATABAR_STACKED
DataBar Expanded	0x00004000	DW_ST_DATABAR_EXP
DataBar Expanded stacked	0x00008000	DW_ST_DATABAR_EXP_STACKED
unrecognized linear	0x01000000	DW_ST_LINEAR_UNDEC
unrecognized PDF417	0x02000000	DW_ST_PDF417_UNDEC
unrecognized DataMatrix	0x04000000	DW_ST_DATAMATRIX_UNDEC
unrecognized QRCode	0x08000000	DW_ST_QRCODE_UNDEC
unrecognized AztecCode	0x00100000	DW_ST_AZTECCODE_UNDEC
DataMatrix	0x10000000	DW_ST_DATAMATRIX
PDF417	0x20000000	DW_ST_PDF417
QRCode	0x40000000	DW_ST_QRCODE
AztecCode	0x80000000	DW_ST_AZTECCODE

Error Codes

Constant	Value	Description
DW_OK	0	Ok
DW_ERROR	1	Error
DW_ERR_IN_PARAM	2	Invalid input parameter
DW_CANT_ALLOC_MEM	3	Can't allocate memory
DW_LIB_NOT_INIT	4	Library is not initialized
DW_ERR_RES_IDX	5	Invalid decoding result index