National Instruments IMAQTM Manual De Usuario

© National Instruments Corporation

This chapter describes how to perform particle analysis on the images. Use 
particle analysis to find statistical information about particles, such as the 
presence, size, number, and location of particle regions. With this 
information, you can perform many machine vision inspection tasks, such 
as detecting flaws on silicon wafers or detecting soldering defects on 
electronic boards. Examples of how particle analysis can help you perform 
web inspection tasks include locating structural defects on wood planks or 
detecting cracks on plastic sheets.

Figure 4-1 illustrates the steps involved in performing particle analysis.

Figure 4-1.  Steps for Performing Particle Analysis

Threshold the grayscale or color image to create a binary image. Creating 
a binary image separates the objects that you want to inspect from the 
background. The threshold operation sets the background pixels to 0 in the 
binary image, while setting the object pixels to a non-zero value. Object 
pixels have a value of 1 by default, but you can set the object pixels to any 
value or retain their original value.

You can use different techniques to threshold the image. If all the 
objects of interest in the grayscale image fall within a continuous range 
of intensities and you can specify this threshold range manually, use 

CWIMAQVision.Threshold

 to threshold the image. 

Create a Binary Image

Improve a Binary Image

Make Particle Measurements

in Pixels or Real-World Units