Hello,
In the example of 3D Time Reversal Reconstruction For A Spherical Sensor, there is a function makecartsphere, which makes a sensor mask of 100 points evenly distributed around a sphere.
But I want to make a spherical sensor mask of 100 points not evenly distributed around the sphere.
Is there an easy way?
thanks a lot!
Hi Marina,
I'm not sure I follow exactly what you're trying to do. Do you mean you would like the sensor points to be randomly positioned over the surface of the sphere, or positioned over a different shaped surface, or something else?
Brad.
Hi Brad,
Actually I mean that I would like the sensor points to be positioned over the surface of the sphere not evenly, that is to say, I can control the distribution of these sensor points over the surface of the sphere. For example,I hope there are more sensor points somewhere (the density of sensor points is bigger) that other places over the surface of the sphere. And all the sensor points are positioned over the same surface of the sphere.
Have I made myself understood?
Thanks.
Marina
Hi Brad,
I am looking forward for your reply soon!
Thanks a lot!
Marina
Hi Marina,
I am not a member of the development team so my answer is not at all "official" but I always define the sensor point myself.
You just have to define the variable "sensor.mask" as a logical grid with the same size as your computational domain and set the value to "true" where you want to record the data.
For example, if you want to record the data at all the points of your domain :
sensor.mask(1:Nx, 1:Ny, 1:Nz) = true;
And then, you run kwave as usual:
kspaceFirstOrder3D(kgrid, medium, source, sensor, input_args{:});
This way, you control exactly where are your sensor points.
Hope it helps :-)
Anthony
Hi Anthony,
It is very very kind of you to reply my question.
If I do as what you said, it is true that I can control exactly where the sensor points are. But I need them to be on the same sphere, so I must make a lot of calculations by myself, instead of using some function like Makeball.
Could you give me more some suggestions to solve this problem?
Thanks a lot !!!
Hi Marina,
Unfortunately, if you want to place your sensor points in arbitrary positions, you will have to write some code to do this. An alternate to using a binary sensor mask as Anthony suggested would be to use a Cartesian sensor mask. This is just a list of the Cartesian coordinates of the sensor points. Using the desired radius of the sphere and the polar angles of your sensor points, it should be simple to calculate their positions.
Brad.
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