Practical Guide to Machine Vision Software: An Introduction with LabVIEW

11OCR (Optical Character Recognition)

OCR (Optical Character Recognition) is machine vision software that translates images of characters into text. To identify characters in an image, the LabVIEW software needs to be trained to identify each character. A data set of trained characters is created and saved as a character set file in advance. The set of trained characters are compared with character objects in an image for recognition.

The example of OCR provided in LabVIEW can be found from the following folders:

C:\Program Files\National Instruments\LabVIEW 2013\examples\Vision\OCR

Figure 11.1 shows the screen-captured image of the example OCR.vi. In this example, characters in the image are recognized and converted into a character string.

Figure 11.1 Example VI for OCR.

Some industrial applications of OCR for machine vision include inspecting labels, sorting, tracking packages, and verifying parts during manufacturing process.

11.1 OCR Using Vision Assistant

Example: OCR

Train the character sets in Figure 11.2 and identify numeric characters in Figure 11.3 via OCR functions. Note that the size and font of the characters may be different from those of the trained characters.

11.1.1 Character Training Using Vision Assistant

The OCR function using Vision Assistant offers an excellent procedure to train the software to recognize the imaged characters. For this ...