Cal. using Vision Ass't v7.0.0 returns wrong units for area measurement.

[DaveD]

I am trying to use NI Motion Assistant ver7.0.0 to measure the area of a scanned image using the Measure, processing function.  After performing a simple calibration to determine the script for pixel to centimeter conversion, the measure function will return the length in centimeters but an area measurement always returns the results in pixels rather than square centimenters.

Calibration was done on a bitmap image of a section of graph paper scanned from a plotter.  I have used this procedure for many years using Image Builder 5.0 and have just upgraded to LabVIEW 7.0 and Vision Assistant 7.0.0.

Another problem is the columns on the screen that display the measurements are so narrow that only 2 digits of the length measurement are displayed.

Dave Deutscher
U of S, Saskatoon SK, Canada

[RManion]

Hi Dave,

If you are describing a VI written in Labview, the column width issue should be fairly easy to correct.  Simply drag the edge of the numeric display in order to expand the width of the item.  If you are not working in LabVIEW, can you please describe what environment you are working with?

If you just upgraded, you should currently be on version 7.1 of LabVIEW and Vision.  Regarding the Measure function, in 7.1 you should be able to use the IMAQ Particle Analysis VI to perform an area measurement using the calibrated datatype. 

Let me know if you have any other questions,

Robert

[DaveD]

For this project I am not using LabVIEW at all.  I am just running Vision Assistant and the "Measure Function" to determine the area of a scanned image (in .bmp format) of a pressure-volume diagram.  After performing a calibration to convert pixels to my desired units, centimeters, the length measurement function works and returns thecorrect length in cm but when I do an area measurement the area is shown in pixels and not cm^2.

I was previously using IMAQ Vision Builder and it worked well for this application, but Vision Assistant came with our LabVIEW upgrade so I thought I should try it out.

Thank You