The communication between field and jitter is done with a mxj objects that behaves like a python box, in the sense that we design the mxj object in field using python. When a Jitter object arrives, the code is executed and the result sent to the outlet.
In order to do that, we have to do the following (one time for each plane):
1. create a zeroed array
2. extract the row vector from JitterMatrix with copyVectorToArrayPlanar
3. use the constructor SimpleMatrix(rows, cols, rowMajor, double) to convert the array into a row SimpleMatrix
4. use .combine method to add all the rows in this fashion
Then we apply a transformation with the ejml java library.
And to recover the JitterMatrix from SimpleMatrix:
1. extractVector gets a 1-row matrix
2. extractVector().getMatrix().getData() gets an array from a 1-row SimpleMatrix
3. set the array as a row of JitterMatrix with copyVectorToArrayPlanar
The problem is the performance, we could not find a way to map the jitter matrices into a java matrix class (SimpleMatrix in our example) without using row or cell descomposition which makes for example the rendering of a 320x320 image last about 3 seconds, which is not suitable for real time.
My questions would be:
a. is possible to optimize the performance of the methods that translate a jitter matrix into another formats (for the moment only floats and arrays)?
b. the same for the methods that fill a jitter matrix with another formats like floats or arrays?
c. is it feasible to build a method that transforms a jitter matrix into a java matrix class and vice versa?
I attach also an example of a filtered image with this technique.