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IMAQ Pattern Matching Does Not Find All Objects



Primary Software:
Primary Software Version: 2012.01
Primary Software Fixed Version: N/A
Secondary Software: N/A

Problem:
I have many objects in my image, and I need to find all of them. IMAQ Pattern Matching only returns a couple of items. What VIs are available to detect all items?

Solution:
The IMAQ Advanced Setup Match Pattern 2 VI allows users to specify the search strategy of IMAQ Pattern Matching.
  1. Open the functions palette and place an IMAQ Advanced Setup Match Pattern 2 VI on the block diagram.
  2. Right-click and select Create»Control from the Advanced Rotation Match Options input on the IMAQ Advanced Setup Match Pattern 2 VI. The Advanced Rotation Match Options control is an array of values, for each initialized array cell the Pattern matching will become more specific to the users needs.
  3. To produce more results change the Setup Data Item to Search Strategy, you can then set the Item Value to 1. This is the conservative search option, it is processor intensive but very accurate, 2 is Balanced - it will find most objects, 3 is Aggressive which is very fast, but you may miss many of the objects.
  4. Double check that the Number of Matches Requested on IMAQ Match Pattern 2 is large enough.
Should you still fail to see all the items, check your camera and lighting settings. The Practical Guide to Machine Vision Lighting linked below contains information on how to easily improve your image, resulting in better pattern matching.

Related Links:
Developer Zone Tutorial: A Practical Guide to Machine Vision Lighting - Part I

Attachments:





Report Date: 05/02/2003
Last Updated: 02/03/2014
Document ID: 2X139CH6

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