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

© National Instruments Corporation

Use 

imaqRejectBorder()

 to remove particles that touch the border of 

the image. Reject particles on the border of the image when you suspect 
that the information about those particles is incomplete.

Use 

imaqSizeFilter()

 to remove large or small particles that do 

not interest you. You can also use the 

IMAQ_ERODE

, 

IMAQ_OPEN

, and 

IMAQ_POPEN

 methods in 

imaqMorphology()

 to remove small particles. 

Unlike 

imaqSizeFilter()

, these three operations alter the size and 

shape of the remaining particles.

Use the 

IMAQ_HITMISS

 method of 

imaqMorphology()

 to locate 

particular configurations of pixels, which you define with a structuring 
element. Depending on the configuration of the structuring element, the 

IMAQ_HITMISS

 method can locate single isolated pixels, cross-shape or 

longitudinal patterns, right angles along the edges of particles, and other 
user-specified shapes. Refer to Chapter 9, Binary Morphology, of the 
IMAQ Vision Concepts Manual for more information about structuring 
elements.

If you know enough about the shape features of the particles you want to 
keep, use 

imaqParticleFilter2()

 to filter out particles that do not 

interest you.

Use 

imaqSeparation()

 or apply an erosion or an open operation 

with

imaqMorphology()

 to separate touching objects. The 

imaqSeparation()

 function is an advanced function that separates 

particles without modifying their shapes. However, erosion and open 
operations alter the shape of all the particles.

A separation is a time-intensive operation compared to an erosion or open operation. 

Consider using an erosion or open operation if speed is an issue with your application.

Use 

imaqFillHoles()

 to fill holes in the particles. Use 

imaqMorphology()

 to perform a variety of operations on the particles. 

You can use the 

IMAQ_AUTOM

, 

IMAQ_CLOSE

, 

IMAQ_PCLOSE

, 

IMAQ_OPEN

, 

and 

IMAQ_POPEN

 methods to smooth the boundaries of the particles. Open 

and proper-open smooth the boundaries of the particle by removing small