Справочник Пользователя для National Instruments IMAQ Vision for LabWindows TM /CVI

Скачать
Страница из 119
Chapter 5
Performing Machine Vision Tasks
© National Instruments Corporation
5-5
b.
If you use 
imaqFindTransformRects()
, specify two 
rectangular objects, each containing one separate, straight 
boundary of the object, as shown in Figure 5-3. The boundaries 
cannot be parallel. The regions must be large enough to include 
the boundaries in all the images you want to inspect.
Figure 5-3.  Locating Coordinate System Axes with Two Search Areas
2.
Use the options parameter to choose the options you need to locate the 
edges on the object, the coordinate system axis direction, and the 
results that you want to overlay onto the image. Set the options 
parameter to 
NULL
 to use the default options.
3.
Choose the mode for the function. To build a coordinate transform for 
the first time, set the mode parameter to 
IMAQ_FIND_REFERENCE
To update the coordinate transform in subsequent images, set this 
mode to 
IMAQ_UPDATE_TRANSFORM
.
1
Primary Search Area
2
Secondary Search Area
3
Origin of the Coordinate System
4
Measurement Area
1
3
2
4
1
3
2
4
b.
a.