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By default, 

imaqReadDataMatrixBarcode()

 assumes the barcode cells 

are square. If the barcodes you need to read have round cells, set the 

cellShape

 element of the options parameter to 

IMAQ_ROUND_CELLS

.

Specify round cells only if the Data Matrix cells are round and have clearly defined 

edges. If the cells in the matrix touch one another, you must set 

cellShape

 to 

IMAQ_SQUARE_CELLS

.

By default, 

imaqReadDataMatrixBarcode()

 assumes the shape of the 

barcode is square. If the shape of your barcode is rectangular, set the 

barcodeShape

 element of the options parameter to 

IMAQ_RECTANGULAR_BARCODE_2D

.

Setting the 

barcodeShape

 element to 

IMAQ_RECTANGULAR_BARCODE_2D

 when 

the barcode you need to read is square reduces the reliability of your application.

By default, 

imaqReadDataMatrixBarcode()

 automatically detects the 

type of barcode to read. You can improve the performance of the your 
function by specifying the type of barcode in your application. IMAQ 
Vision supports Data Matrix types ECC 000 to ECC 140, and ECC 200.

Use 

imaqReadPDF417Barcode()

 to read values encoded in a PDF417 

barcode.

imaqReadPDF417Barcode()

 can locate automatically one or multiple 

PDF417 barcodes in an image. However, you can improve the inspection 
performance by locating the barcodes using one of the techniques described 
in this chapter. Then pass in the ROI location to 

imaqReadPDF417Barcode()

.

If you need to read only one barcode per image, set the searchMode parameter to 

IMAQ_SEARCH_SINGLE_CONSERVATIVE

 to increase the speed of your application.

You can overlay the results obtained at various stages of you inspection 
process on the window that displays your inspection image. The software 
attaches the information that you want to overlay to the image, but it does 
not modify the image. The overlay appears every time you display the 
image in an external window.