CHAPTER 9. POS TERMINAL
71
These LabVIEW techniques are also required for this project:
•
– Create a custom control for the
Barcodes
Vision Assistant script output and insert this into the data highway
•
–
Format Into String
•
– Use
IMAQ Overlay Text
to insert a text string into the
nondestructive image overlay
•
– Select the “NI Vision” font and adjust its size
•
Create “Inventory” Cluster of Arrays
– Create a cluster of arrays to store
the product inventory with item codes, names, and values
9.2
Development Tips
Representative Images
•
Gather at least five items that contain barcodes.
•
Conduct an Internet search to learn more about the structure of an EAN-13
barcode and write a paragraph to describe your findings. Also look for
a site that can generate an EAN-13 barcode given a user-supplied value.
•
Determine the camera distance and camera mode (resolution and frame
rate) that achieves your required spatial resolution while maximizing the
frame rate.
•
Experiment with your barcode items to determine a suitable background
color; you may find that a piece of white paper works well to protect the
surface of the table-top camera copy stand. Ambient room light should suf-
fice; keep the lighting as uniform as possible to avoid lighting “hot spots.”
•
Use a line grid target to align the camera so as to minimize perspective
distortion.
•
Adjust the camera attributes to maximize the contrast of the barcode’s
black-and-white pattern. The NI Vision Assistant
Barcode Reader
step is
robust and should be able to ignore the other features visible on the object.
(2:58)
10
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11
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12
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13
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Содержание NI myRIO
Страница 1: ...Ed Doering NI myRIO Vision Essentials Guide...
Страница 2: ......
Страница 11: ...Part I Machine Vision Fundamentals...
Страница 12: ......
Страница 31: ...Part II Introductory Machine Vision Projects...
Страница 32: ......
Страница 38: ...32 CHAPTER 4 CAMERA SETUP...
Страница 44: ...38 CHAPTER 5 STEREO VISION...
Страница 61: ...Part III Machine Vision Application Projects...
Страница 62: ......
Страница 72: ...66 CHAPTER 8 COIN COUNTER...
Страница 85: ...CHAPTER 10 KEYED OPTICAL LOCK 79 Figure 10 3 Typical expected results for the Geometric Matching step...
Страница 86: ...80 CHAPTER 10 KEYED OPTICAL LOCK...
Страница 92: ...86 CHAPTER 11 DMM TEST STAND...
Страница 134: ...128 CHAPTER 17 MARBLE SORTER...
Страница 135: ...Part IV Appendices...
Страница 136: ......
Страница 143: ...B MXPandMSPConnectorDiagrams Figure B 1 MXP myRIO eXpansion Port connector diagram...
Страница 144: ...138 APPENDIX B MXP AND MSP CONNECTOR DIAGRAMS Figure B 2 MSP miniSystem Port connector diagram...
Страница 148: ...142 APPENDIX D BUILD A STAND ALONE APPLICATION...
Страница 149: ...E MarbleSorterConstructionDetails To be continued...
Страница 150: ...144 APPENDIX E MARBLE SORTER CONSTRUCTION DETAILS...