Best Approach for Radial Image Drawing - Sector Scan Sonar

[PeterGross]

This is not a problem, but asking for opinions on best approach.

I need to image data from a sector scan sonar.  This device rotates 360 degrees (sub degree segments) and generates a series of data points from the origin - radially outward at a step angle - to an end point.  Hence, for each sonar 'ping' I need to graph data points from the center of a circle, outwards at a radial angle.

I"m not sure if I should be using LabView vi tools for drawing, or going to ActiveX or  ? ? ?

Does anyone have a suggestion on the best approach for this?

Thanks
Peter

[LucaP.]

Hi Peter

I would have a look at the "Polar Plot Demo.vi" which you find in the LabVIEW Example Finder. I think it shows what you're looking for,

[aeastet]

I was working with someone the other day on this type of plot. The application is different but the theme should be the same.

http://forums.ni.com/t5/LabVIEW/calculating-mean-value-of-sorted-data-and-drawing-polar-plot/m-p/118...

[PeterGross]

Thank you Luca, appreciate your comments.

I am aware of the polar plot vi.  The problem is that I need to plot each radial line from origin to the end, with several hundred data points of varying intensity.  The polar plot vi won't allow that.

So I"m thinking either modify that vi myself, or write my own routine  - perhaps in ActiveX.

I"m trying to get some expert opinions of people who have had similar drawing challenges in LabView

Cheers

Peter

[PeterGross]

Thanks for the note.  That's not quite what I need.

Here's an example of a 360 degree plot of acoustical data.  I need to create something like this.

[aeastet]

Do you have a data file to play with?

[PeterGross]

I do have several data files, but they are quite large.

The data is an array of bytes.  Each radial line consists of 1024 bytes, each byte representing an intensity value.  Hence, for each degree around the circle I have an array of 1024 intensity values that need to be plotted from the circle origin outwards.

[Tom_Limerkens · Accepted solution]

Peter,

You could use a LabVIEW intensity chart for that kind of display.

Maybe not the most performant way, but it is possible.

In attachement I have made an example with your specifications.

1024 datapoints per degree

See image as example :

Basic principle :

- Create data matrix of 2048 x 2048 points

- For each 'angle line' calculate what pixel to replace for each datapoint in the line

- Because the 'datapoints' become bigger further from the center, repeat the action for several 'sub angles' . eg for 85 deg. also calc. 84.6, 84.8, 85, 85.2, 85.4

It gives you an idea for the possibilities, but performance optimization might be required.

- Calc only outer x pixels over more degrees

- Do some kind of anti aliasing to avoid pixelated lines.

See example attached. (LV 8.6)

[Tom_Limerkens]

Some more examples showing possibilities of intensity plot.

Success.

Tom

[PeterGross]

That's absolutely EXACTLY what I"m trying to do.

Excellent suggestion Tom!

I really appreciate this focused advise.  I was very ambiguous of the best approach and you nailed it.

Warm Regards

Peter