polar plot of a data matrix....help is needed

[underzero]

Hello,

I'm working on an Ultrasound project, the data coming from the device is transmitted through a USB driver to the PC. I made a VI, that open a connection with the USB device and recieve the data. The coming data are recognized by the LabVIEW as stream of strings, so, i converted the data into a bytes using "string to byte array" function, then I used the function "reshape array" to reshape the data bytes into a 512x64 matrix which represents the no. of samples per ultrasound line times the no. of ultrasound lines.

I plotted the data on an intensity graph function and it worked, but the problem is that the data or the matrix must be plotted as a polar plot, not as a cartesian plot.

The problem is that I want to convert each single pixel (byte) of the (512x64) matrix from having (x,y) coordinate into a pixel that has (r, angle) coordinate.

can you help me plot these data in a polar plot. If any body has any suggestions please help.

best regards,

Underzero.

[RSibagatullin]

Rectangular to polar coordinate conversion should be very easy. You can check this link:


http://www.teacherschoice.com.au/Maths_Library/Coordinates/polar_-_rectangular_conversion.htm


Message Edited by RSibagatullin on 07-02-2008 05:13 PM

[altenbach]

You can use the "RE/IM to polar" from the "numeric...complex palette".

[smercurio_fc]

Also, once you have your data using the above function you can use the Polar Plot VI to generate a polar plot. You will find this VI in the Graphics & Sound -> Picture Plots functions palette.



There is an example that ships with LabVIEW to show you how to do polar plots. Run the Example Finder (Help -> Find Examples), and search for "polar".


Message Edited by smercurio_fc on 07-02-2008 05:36 PM

Message Edited by smercurio_fc on 07-02-2008 05:36 PM

[altenbach]

The "polar plot" is a line plot and the OP seens to want a picture.

Most likely you can loop over the pixels of the 2D intensity graph and map into your data array with transformed indices.

Do you have a typical dataset that you could attach?

[underzero]

Thanks all of you.....

First, I've searched the LabVIEW help and the examples, but all of it didn't work, and I guess the proper solution is to map the matrix according to the polar coordinates like this: ( r cosq, r sinq )  ð  ( x, y )

The angle q extends from 0 degree to 90 degree ==> the intensity graph plot area.

Now, I've to write down a formula to move about every single pixel in the intensity graph area and apply the above operation to obtain the new coordinates of every pixel.

I think I've to make a loop, I'll try.

Your help is appreciated.

Thanks alot RSibagatu…, altenbach, and smercurio…

Best regards,

Underzero.

[smercurio_fc]

---

@altenbach wrote:

The "polar plot" is a line plot and the OP seens to want a picture.

---

I didn't get that impression, but you may be right. Not sure.

[altenbach]

Here's a random ultrasound picture from the internet with some annotations added.

Typically, the scan lines are displayed radially as shown, but I would think the raw data is probably square with y=R and x=theta.

Just a wild guess. 🙂

All we need is a simple remapping in 2D, but we would need to know the x and y axis scaling.

Message Edited by altenbach on 07-03-2008 07:43 AM

[phani466]

Hi 

I need your help to Plot the data (512bytes) which is coming from PSOC through USB.

now i am able to read the data(512bytes) in labVIEW as a Bulk data but i want to plot the data(512bytes) as like analog waveforms (X and Y graph) in LabVIEW.

I am Using LabVIEW14.0. 

Thanks 

Phani

[altenbach]

Instead of adding to a 7 year old unrelated thread, you should start a new thread instead.

Please explain (maybe with an example) what you mean by "bulk data". How is the data arrannged? What is X and what is Y?