National Instruments IMAQTM - Manual (Page 18)

© National Instruments Corporation 2-1 IMAQ Vision for Visual Basic User Manual
2
Getting Measurement-Ready
Images
This chapter describes how to set up an imaging system, acquire and
display an image, analyze the image, and prepare the image for additional
processing.
Set Up Your Imaging System
Before you acquire, analyze, and process images, you must set up an
imaging system. The manner in which you set up the system depends on the
imaging environment and the type of analysis and processing you need to
do. Your imaging system should produce images with high enough quality
so that you can extract the information you need from the images.
Follow the guidelines below to set up an imaging system.
1. Determine the type of equipment you need based on the space
constraints and the size of the object you need to inspect. For more
information, refer to Chapter 3, System Setup and Calibration, of the
IMAQ Vision Concepts Manual.
a. Make sure the camera sensor is large enough to satisfy the
minimum resolution requirement.
b. Make sure the lens has a depth of field high enough to keep all of
the objects in focus regardless of their distance from the lens.
Also, make sure the lens has a focal length that meets your needs.
c. Make sure the lighting provides enough contrast between the
object under inspection and the background for you to extract the
information you need from the image.
2. Position the camera so that it is parallel to the object under inspection.
If the camera acquires images of the object from an angle, perspective
errors occur. Even though you can compensate for these errors with
software, NI recommends that you use a perpendicular inspection
angle to obtain the fastest and most accurate results.
3. Select an image acquisition device that meets your needs. National
Instruments offers several image acquisition devices, such as analog