I need to convert an image into an matrix to do math with it, like what is done with Matlab (imadd, imsubtract, immultiply, imdivide).
I only managed to do this:
CvMat mtx = new CvMat(iplUltima);
opencv_core.cvTranspose(mtx,mtx);
iplUltima = new IplImage(mtx);
pbxImagenTransformada.setIcon(new ImageIcon(iplUltima.getBufferedImage()));
but when I try to do the same with cvSum or cvAdd I got errors. Can you give me an example of use? I tried to replace cvTranspose by cvAdd but it is an error.
Related
I have got a question regarding array's visualization in R. There is an image() function which makes a 2d-image based on the matrix that it is received; however, this function are not valid for arrays.
So, how is it possible to make a 3d-image through a 3d-array?
For instance:
y<-matrix(round(runif(144)),nrow = 12,ncol = 12,byrow = TRUE)
image(y, axes=F)
Now how we can make a 3d image if we have:
y=array(data=round(runif(12*12*12))+1,dim = c(12,12,12))
Regards,
Shapour
there is image3d function in misc3d:
library(misc3d)
library(rgl)
y=array(data=round(runif(12*12*12))+1,dim = c(12,12,12))
image3d(y)
I was experimenting with GameplayKit’s GKAgent3D class to move a SCNNode within a scene. I was able to update the SCNNode with the agent’s position, but not rotation. The issue being the agent’s rotation is stored as a matrix_float3x3, which doesn’t match any of data types SceneKit uses for storing rotational information.
So what I’d like to know is if there’s a simple function or method that could convert a rotation stored as matrix_float3x3 to any SceneKit data types?
To expand on #rickster 's answer, here's a nice way to take the top-left 3x3 of a 4x4 matrix in Swift, taking advantage of the expanded simd support in the iOS 11/ tvOS 11/ High Sierra version of SceneKit:
extension float4 {
var xyz: float3 {
return float3(x, y, z)
}
init(_ vec3: float3, _ w: Float) {
self = float4(vec3.x, vec3.y, vec3.z, w)
}
}
extension float4x4 {
var upperLeft3x3: float3x3 {
let (a,b,c,_) = columns
return float3x3(a.xyz, b.xyz, c.xyz)
}
init(rotation: float3x3, position: float3) {
let (a,b,c) = rotation.columns
self = float4x4(float4(a, 0),
float4(b, 0),
float4(c, 0),
float4(position, 1))
}
}
Then, to update your agent to match your node's orientation, you'd write:
agent.rotation = node.simdTransform.upperLeft3x3
Or, if the node in question is not at the "root" level (as in, a direct child of the rootNode), you might want to use the node's worldTransform:
agent.rotation = node.simdWorldTransform.upperLeft3x3
EDIT: If the node in question has a dynamic physics body attached, or is being animated with an SCNTransaction block, the node's presentation node will more accurately reflect its current position on screen:
agent.position = node.presentation.simdWorldPosition
agent.rotation = node.presentation.simdWorldTransform.upperLeft3x3
EDIT: added code above for going in the other direction, moving the node to match the agent.
node.simdTransform = float4x4(rotation: agent3d.rotation, position: agent3d.position)
Note that if you have a physics body attached to the node, it should be kinematic rather than dynamic if you're going to be directly modifying the node's transform in this way.
SceneKit takes transform matrices as SCNMatrix4, and provides utilities for converting from SIMD matrix_float4x4: init(_ m: float4x4) for Swift and SCNMatrix4FromMat4 for ObjC/C++.
Sadly, I don't see a built-in way to convert between SIMD 3x3 and 4x4 matrices using the assumption that the 3x3 is the upper left of the 4x4. (Seems like you'd expect that in the SIMD library, so it's worth filing a bug to Apple about.)
But it's not too hard to provide one yourself: just construct a 4x4 from column vectors, using the three column vectors of the 3x3 (padded out to float4 vectors with zero for the w component) and identity for the fourth column (0,0,0,1). (Implementation code left for the reader, partly because I don't want to write it for three languages.) After converting float3x3 to float4x4 you can convert to SCNMatrix4.
Edit: In iOS 11 / tvOS 11 / macOS 10.13 (why didn't they just call this year's macOS version 11, too?), SceneKit has a whole parallel set of APIs for using SIMD types like float4x4 directly; e.g. simdTransform. However, you still need to convert a 3x3 to a 4x4 matrix.
I am trying to create an array of structures in Simulink and got some problems with it.
first of all i tried to create it directly in Simulink using this:
function a = fcn(Dibhole, t , x, const)
%#codegen
%Output = zeros(10,10);
f1 = 'number';
f2 = 'move';
cube = struct(f1, 0, f2, 0);
a = repmat(cube, 20, 10);
for i = 1:20
for j = 1:10
a(i,j).number = 0;
a(i,j).move = 0;
end
end
and i got this error:
Derived output was of type struct. 'Inherited type' is unsupported for this
type and a defined bus object must be used instead. Click on 'a' and
set data type for 'a' to be 'Bus: ', where '' is
the name of a bus object from the MATLAB workspace.
So i found some example how to create struct in Matlab and receive this to Simulink: http://blogs.mathworks.com/seth/2011/12/05/initializing-buses-using-a-matlab-structure/
That works perfectly but i still can't repeat this with array:
f1 = 'number';
f2 = 'move';
cube = struct(f1, 0, f2, 0);
myStruct2 = repmat(cube, 20, 10);
for i = 1:20
for j = 1:10
myStruct2(i,j).number = 1;
myStruct2(i,j).move = 1;
end
end
busInfo = Simulink.Bus.createObject(myStruct2);
Can anyone clarify to me what's the problem? Or maybe there is different way to create array of struct in Simulink?
Mihail
Simulink wants you to define the output of the function to be a bus.
As 'Bus: My_test_bus', for example.
Take a look at the Simulink Bus Editor. You can find it in any model under the menu, Edit->Bus Editor.
This would be a good start.
Rick, i think you are right!
i have tried this problem for a long time, and have got this results:
the irony is that I was never able to create array of structures BUT i did this with structure of arrays! :D
I made this steps for it:
to use structure of arrays we need to define and initialize it in some MATLAB function. Like this:
number = zeros(10,1);
move = zeros(10,1);
for i = 1:10
number(i,1) = i+1;
move(i,1) = i+2;
end
a = struct('numbers',number,'movement', move);
To work this data we must use Bus Selector.
So we have array in "numbers" and "movement".
BUT! Here we go, Rick: we must define type of output of MATLAB function like Bus! How to do this in simulink? i found this way:
in model properties in simulink Callbacks/PreLoadFcn define some function and in same folder as project create .m file named like this just defined function.
In this file create structure of array and define Bus type for it:
number = zeros(10,1);
move = zeros(10,1);
a = struct('numbers',number,'movement', move);
busInfo = Simulink.Bus.createObject(a);
Now we have Bus type for our structure at first loading of simulink model.
Last step: define MATLAB function output type directly.
in Model Explorer choose your MATLAB function. choose output variable. Set DataType for it: Bus:slBus1 (the name of this Bus type you can see in wokspace of matlab, because its a global variable).
That's all! now it works!
(tried to add pictures, but i have no enough reputation :( )
Now my program works in this way, but i also tried to create array of structures and still have the problems. i tried to create Bus for it, but can't transmit it to Bus Selector - it doesn't know what to do with structures... i also tried to add one more MATLAB function to create some data from structures and then display it, but it doesn't works too(
I am learning to build a surface using JMonkey api. The class Surface has a method
createNurbsSurface(controlPoints, nurbKnots, uSegments, vSegments, basisUFunctionDegree, basisVFunctionDegree).
I am trying to make a simple example to understand the meaning of the arguments. However, I can't initialize the second argument:
List<Float>[] nurbKnots
I tried:
List<Float>[] nurbKnots = {new ArrayList<Float>()};
but it complains that you cannot create a generic array of List<Float>.
Could someone show me how to initialize this nurbKnots.
It works for non-generic List:
List[] listNonGeneric = new ArrayList[10];
But this won't work:
List<Float>[] listGeneric = new ArrayList<Float>[10];
You have to use:
List<List<Float>> nurbKnots = new ArrayList<>();
and pass the argument as
(List<Float>[])nurbKnots.toArray();
One friend helped. He told me:
In Java, it's not really possible to have arrays of generic types (safely). You have to allow unchecked assignment. Something like:
#SuppressWarnings("unchecked")
List<Float>[] f = new List[2];
f[0] = new ArrayList<Float>();
f[0].add(0.1);
f[1] = new ArrayList<Float>();
f[1].add(0.2);
But, it worked!
I'm trying to convert the byteArray of a Sound Object to an array with floats. The Sound Object plays back fine & at full length, but the float Array i get from it is cut off (but sounds correct), so i must be doing something wrong in the conversion:
var s:Sound = mySound;
s.play(); // plays fine
var bytes:ByteArray = new ByteArray();
bytes.endian = Endian.LITTLE_ENDIAN;
s.extract(bytes, s.bytesTotal, 0);
var leftChannel:Array = new Array();
var rightChannel:Array = new Array();
bytes.position = 0;
while (bytes.bytesAvailable)
{
leftChannel.push(bytes.readFloat());
rightChannel.push(bytes.readFloat());
}
and this is what i get:
The top two channels are the original Sound Object.
The lower two is the float Array Data. I aligned them so you can see that the beginning is cut off and obviously the length is incorrect.
Thanks for any answers...
ok there were two problems:
the mp3 file i was importing was somehow corrupt, that caused the beginning to be cut off
the length i defined to extract was not correct, to find the full sound length use
var numTotalSamples:Number = int(s.length * 44.1); //assuming 44.1kHz sample rate
then:
s.extract(bytes, numTotalSamples, 0);