Figure 5-4. building a coordinate transform – National Instruments IMAQ Vision for LabWindows TM /CVI User Manual

Page 59

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Chapter 5

Performing Machine Vision Tasks

© National Instruments Corporation

5-7

IMAQ Vision for LabWindows/CVI User Manual

Choosing a Method to Build the Coordinate Transform

Figure 5-4 guides you through choosing the best method for building a
coordinate transform for your application.

Figure 5-4. Building a Coordinate Transform

Start

Yes

Yes

Yes

Yes

Yes

No

No

No

No

Object positioning

accuracy better

than ±65 degrees.

The object under

inspection has a straight,
distinct edge (main axis).

The object contains

a second distinct edge not

parallel to the main axis in a

separate search area.

The object contains a

second distinct edge not parallel

to the main axis in the same

search area.

Build a coordinate

transformation based on

edge detection using two

distinct search areas.

Build a

coordinate transformation

based on edge detection

using a single search area.

Object positioning

accuracy better

than ±5 degrees.

Build a coordinate

transformation based on

pattern matching

shift invariant strategy.

Build a coordinate

transformation based on

pattern matching

rotation invariant strategy.

End

No

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