process spectrometer CCD images help

[spencerchen]

Hi, All,
I am using JY's Triax 320 with CCD 3000 to take the data, the data is a 100pixel*256pixel image, but only 2*2pixel laser spot value is what I need. The laser beam will scan from the top to the bottom of the CCD,  now I need to pickup the 2*2 pixel value from every frame of the image and save into a file. Since there are more than 1000 frames, It is very low efficient to just save every single frame to pickup the laser spot value by hand. I am wondering if there is any efficienct way to pick up those 2*2 pixel value automatically then I don't have to save all the images. Thanks a million.

[DOC-doc]

Hi Spencerch...

May I reformulate your question (to be shure I understood it) : you are taking a serie of 1000 images and you want to locate in it the position of a 2x2 pixel bright spot that corresponds to you laser spot  and save this to a file :

wire the "new image" VI to a loop. In the loop wire the image to the "grab image" VI (you have to use the list vi to get the name of the file), then wire it to "Imaq threshold" VI with a constant value of 125 (if bright spot is saturated), then wire it to "IMAQ Particle Analysis " VI ans select in the input "center of mass X" and "center of mass y" and there you get your position .

Cheers.

PS : If you need a quick professional dev., you can contact me at www.machinevision.ch.

Message Edité par DOC-doc le 02-02-2007 10:21 AM

[spencerchen]

DOC-doc, thanks for your reply. I think I need to make it more clear about my question.

I don't output image as files yet but just simpily display on front panel chart.
My data is actually a 2D array(256*100), I already got the array, but I need to save the value of 4 bright pixel counts from the array(corresponding to the laser spot).
The laser spot intensity will change as it scans from the top to the bottom of the CCD, that's why I need to record the bright spot counts value.
But I don't know where the bright spot is, I need to compare each pixel counts value and pick up the  largest 4 values.  The CCD array element counts is about 800-1000 counts(noise level)
except the laser spot's pixel count is between 10,000 to 64,000(saturation value). 

[T-Route]

Hello Spencerch..,

If the pixel values are in a 2D array format then you can simply traverse the array and save any values above a certain threshold.  You could then add these large values to another array and then save that array to a file using which ever file writing method you prefer.  Let me know if this is not possible. 

Regards,
Mark T
Applications Engineer
National Instruments