Hardware manual
Impact Reference Guide Readers Drawer
3-157 Datalogic Automation Inc.
2. Click the ROI radio button. Move and size the ROI so it crosses all the bars in the barcode. Note that
the ROI can extend over background clutter. It can begin in the quiet zones on the left and right of the
barcode, it can be angled across the barcode, and it does not have to be perpendicular to the bars.
3. The detected edges are displayed on the image.
Important: Adjust the threshold and sensitivity options in the Line ROI selection area until all the bar-
code edges are marked in the image with blue points.
Subpixel detection is used automatically. Gradient and Grey Level edge detection types are supported.
In cases where Gradient edge detection picks up extra edges in a noisy image, Grey Level may offer
better results.
4. Select the number of barcode scan lines in the Scan Lines ROI area. By default the tool uses one scan
line, which is the fastest operation on easy applications. To increase the number, and the accuracy,
enter the value in the "Number of Scan Lines" property. (A maximum of ten is recommended.)
In the example below, the number of scan lines is set to ten and "Display Scan Lines" is checked. The
tool automatically determines the height of the barcode, equally spaces the lines vertically, and rotates
them so they are perpendicular to the barcode. All the scan lines pass through all the bars. The scan line
length is equal to the original ROI length. Even if the barcode is rotated so that the ROI misses some of
the bars, the tool still reads the code. If you use multiple scan lines, you also need to adjust the "Percent
of Scan Lines That Must Pass" property on the Pass/Fail setup screen.
5. Click the Pass/Fail radio button. The "Find" selection is set to "Any Type" by default. This means the
tool automatically tries to determine the barcode type and display it in the "Barcode Type Found" prop-
erty. If the tool finds a supported type, you can press the "Train Type" button to set the "Find" property