I need to measure a "blob" in an image...

Ok, here's the deal. I have an experiment setup where a blob of colored liquid spreads under a clear plastic sheet. I am using a normal digital camera to record the process. I'd like to use labview to automate the measurement of the blob. So... I need labview to take a standard AVI file, grab each frame and give back the maximum height and width (bounding rectangle?) of "circular" blob in that frame, and do so through the whole video clip. Can anyone tell me exactly what software I need.. (Labview and Vision Develop. Module?) and maybe some hints on how to do that in Labview...?

It sounds like you will have pretty good contrast between the blob and the background, so that shouldn't be a problem.
LabVIEW and the Vision toolkit should take care of your problem. You can use the AVI routines that come with IMAQ to read each image from the AVI file. You can do automatic thresholding to convert the image to a binary image, and use the blob analysis functions to measure almost any quantity you want - width, height, area, equivalent circle diameter, etc.
If you have any control over the creation of the AVI, set the quality as high as possible. Loss of detail due to compression is most likely to be your biggest problem.
Bruce
Bruce Ammons
Ammons Engineering

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Hi Julia,
Thanks for the response. As I stated before, I have tried all of the examples available that apply. There are only three and one of those uses two counters. The two I have tried are:
Examples/Hardware Input and Output/Counter Measurements/Digital Frequency/
DigFreq-Buff-Cont-ExtClk-ArmStart.prj and
DigFreq-LowFreq1Ctr.prj
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[svn:fx-trunk] 8531: If using an embedded font, need to measure the text with it so that if auto-sizing, the correct amount of space is allocated.

Revision: 8531
Author:   [email protected]
Date:     2009-07-13 12:25:57 -0700 (Mon, 13 Jul 2009)
Log Message:
If using an embedded font, need to measure the text with it so that if auto-sizing, the correct amount of space is allocated.
QA Notes:
Doc Notes: SDK-22205.
Reviewers: will be Gordon
Ticket Links:
    http://bugs.adobe.com/jira/browse/SDK-22205
Modified Paths:
    flex/sdk/trunk/frameworks/projects/spark/src/spark/primitives/RichEditableText.as

Revision: 8531
Author:   [email protected]
Date:     2009-07-13 12:25:57 -0700 (Mon, 13 Jul 2009)
Log Message:
If using an embedded font, need to measure the text with it so that if auto-sizing, the correct amount of space is allocated.
QA Notes:
Doc Notes: SDK-22205.
Reviewers: will be Gordon
Ticket Links:
    http://bugs.adobe.com/jira/browse/SDK-22205
Modified Paths:
    flex/sdk/trunk/frameworks/projects/spark/src/spark/primitives/RichEditableText.as

Regarding Need to measure the rotation count of the Compass either by clockwise and anti clock wise from 0 to 360 degree

Dear All,
Since I am new bee for labview, I want to count the no. of rotations that the compass will be rotating. I just did for one count, but I need to measure the count continuosly. Please some one to help me as soon as possible. Attached is me code. Please do the needful.
Thanks and Regards,
Dinsulpri
Attachments:
Compass Count.vi ‏10 KB

The event structure reads the value and, depending on its last state and current state, makes a decision. You should try to look at the logic in the different states and follow what it happening.
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Simple in line frequency counter? Need to measure 48hz variable resistor

Confused.
Been searching all day. Is there a simple way to measure if I've correctly adjusted a variable resistor from 50hz to 48hz?
Below is the email to me from Russia, explaining how to adjust the variable resistor.
This is variable resistor adjust a speed of motor.
But, you need frequency measuring device for check a value of speed.
You can connect measuring device to Pilot signal socket .
50 hz signal = 25 fps.
48 Hz signal = 24 fps.
Other idea, you can take frequency from resistor R6 on PCb.
25 fps = 500 Hz
24 fps = 480 Hz.
Attachments:
image005.jpg ‏23 KB

Hi Djwerk,
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http://forums.oracle.com/forums/message.jspa?messageID=9385314#9385314
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