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Re: Image processing of laser lines for DEM

Posted by Michael Schmid on May 04, 2010; 10:03am
URL: http://imagej.273.s1.nabble.com/Image-processing-of-laser-lines-for-DEM-tp3688407p3688408.html

Hi Dave,

if suitable background subtraction does not help to get continuous  
lines (did you try 'Subtract Background' or the background  
subtraction of the 'Fast Filters' at http://imagejdocu.tudor.lu/ with  
various options?):
If the spacing between the lines is larger than the longest gap,  
dilate the thresholded lines (Process>Filters>Maximum or Minimum  
might be better because it has a circular, not square kernel). Then  
skeletonize the lines.

Michael
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On 3 May 2010, at 20:31, Dave Luzi wrote:

> Hi, I have not posted here before and if my request is unclear feel  
> free to inform me. I have images where I have taken pictures of a  
> surface and use line lasers to illuminate the surface in order to  
> obtain elevations. Each image has 5 laser lines. The processing  
> into real world coordinates is done in Labview, but I am  
> preprocessing the images in ImageJ. Currently, I run a macro where  
> I despeckle, subract a value and multiply a value of an image in  
> order to reduce noise and light for processing. Unfortunately some  
> of the laser lines either are not continuous or the pixel values  
> are not high enough above my processing threshold. As a result I  
> have to go through each image to ensure that the laser lines are  
> complete ( tracing lines by the cursor and filling in the spaces),  
> there are 90 images per sample and I have about 100 samples  
> (current time is 4-5 min per image---so I will be busy for a long  
> time). Is there a way to run a macro which would interpolate  
> between gaps in the laser automatically?
>
> I am unsure whether to append an image file as an example they are  
> 1281 KB, if this would help please let me know and I can post an  
> example.
>
> dave