F_VN_GradeQRCodeExp

Syntax

Definition:

FUNCTION F_VN_GradeQRCodeExp : HRESULT
VAR_INPUT
    ipSrcImage            : ITcVnImage;
    ipDecodedData         : Reference To  ITcVnContainer;
END_VAR
VAR_IN_OUT
    stCodeGrades          : TcVnCodeGradesQR;
END_VAR
VAR_INPUT
    fModuleWidth          : REAL;
    ipResultVisualization : Reference To  ITcVnImage;
    ipMarginGrades        : Reference To  ITcVnContainer;
    ipContour             : Reference To  ITcVnContainer;
    hrPrev                : HRESULT;
END_VAR
VAR_OUTPUT
    fAngleDeg             : REAL;
END_VAR

 Inputs

 In/Outputs

 Outputs

 Return value

HRESULT

Further information

The function F_VN_GradeQRCodeExp is an expert variant of F_VN_GradeQRCode. It contains additional parameters.

Parameter

Input image

The input image ipSrcImage must be an 1-channel image with element type USINT (8 bits). The input image may only contain the code to be checked, including the corresponding quiet zones.

To achieve meaningful results, uniform illumination, not underexposed or overexposed, good focusing on the code plane and an image sensor plane aligned parallel to it are required. Furthermore, the image resolution must be high enough for the module size. For 2D codes, the smallest module should be covered with at least 5 pixels in order to achieve good results.

Read data

The data read from the code are returned as a string in the container ipDecodedData. The container is of the type ContainerType_String_SINT. Once the code has been successfully found and decoded, the content can be exported to a string using the function F_VN_ExportContainer_String.

hr := F_VN_ExportSubContainer_String(ipDecodedData, sText, nMaxLength, hr);

Different decoding results Decoding with the respective reference algorithm can lead to deviating results. It is therefore possible that the code content can be read by other devices or functions, but the reference algorithm fails.

Presentation of results

ipResultVisualization returns an image with the visualization of the scan grid and the respective evaluation results. The modules are color-coded according to the individual grades: >= 3 as green, >= 2 as light blue, >= 1 as orange, < 1 as red. This parameter is optional and can be set to 0 if it is not required.

Margin information

ipMarginGrades returns additional information on the individual margin ratings of each module for a more detailed evaluation. The return vector of the type ContainerType_Vector_TcVnVector3_REAL contains the X and Y position of the center points and the grade for each module. This parameter is optional and can be set to 0 if it is not required.

Position of the code

The parameter ipContour returns the code corner points as four contour points of the type ContainerType_Vector_TcVnPoint2_DINT. The corner points are in the middle of the outer modules. The contour can be drawn directly with F_VN_DrawContours, for example, or further analyzed with the Contour Analysis functions. This parameter is optional and can be set to 0 if it is not required.

Rotation angle ^{(return value)}

fAngleDeg returns the clockwise rotation angle in degrees.

Application

The print quality of a QR code can be determined in this way, for example:

hr := F_VN_GradeQRCodeExp(
    ipSrcImage              := ipSrcImage,
    ipDecodedData           := ipDecodedData,
    stCodeGrades            := stCodeGrades,
    fModuleWidth            := fModuleWidth,
    ipResultVisualization   := ipResultVisualization,
    ipMarginGrades          := ipMarginGrades,
    ipContour               := ipContour,
    hrPrev                  := hr,
    fAngleDeg               => fAngleDeg);

Required License

TC3 Vision Code Quality

System Requirements