java如何使用包含物理坐标系的标称和测量数据点的输入数组来计算估计的x'y'z?
我的要求是在Java中提供一个函数,该函数使用线性代数在三维坐标系中查找“校准”的xyz位置。下面是我试图实现的接口。如果需要,可以更改参数以适合特定的库
/**
* Given a nominal target xyz point within a three dimensional robotic coordinate system, calculate the theoretical x'y'z'
* transformation using input arrays that represent the nominal coordinates and actual measured coordinates corresponding to
* each nominal point.
*
* @param nominalPoints - a sampling of nominal values (per engineering specs) for a 3-axis robotic system
* e.g. double[][] nominalPoints = new double[][]{
* new double[]{30.0d, 68.0d, 1.0d},
* new double[]{50.0d, 6.0d, 1.0d},
* new double[]{110.d, 20.0d, 1.0d},
* new double[]{35.0d, 15.0d, 1.0d},
* new double[]{45.0d, 97.0d, 1.0d}
* };
* @param actualPoints - actual/measured values corresponding to the nominal data points. These points represent the
* variance from nominal due to manufacturing tolerances.
* e.g double[][] measuredPoints = new double[][]{
* new double[]{30.5d, 68.1d, 1.01d},
* new double[]{50.4d, 6.2d, 1.02d},
* new double[]{110.3d, 20.3d, 1.03d},
* new double[]{35.2d, 15.4d, 1.04d},
* new double[]{45.1d, 97.5d, 1.05d}
* };
* @param targetPoint - an x/y/z point in system to transform into an estimated value based on a least-squared evaluation of the
* nominal and actual arrays
*
* e.g. float[] targetPoint = new float[]{75.21f, 17.56f, 2.765f};
*
* @return
*/
public float[] getCalibratedPoint(float[][] nominalPoints, float[][] actualPoints, float[] targetPoint);
下面的代码是一个解决方案,我被告知它可以在Python中使用numpy,但我对线性代数一窍不通,很难在Java中找到实现。具体地说,我还没有找到与np等价的词。hstack(…),NP一(),,还有一个最小二乘函数,它接受两个数组参数,比如np。利纳格。lstsq(..)。到目前为止,我已经研究了apachecommons和EJML
import numpy as np
# These are the points in the Tray Coordinate System.
primary = np.array([[40., 1160., 0.],
[40., 40., 0.],
[260., 40., 0.],
[260., 1160., 0.]])
# These are points in the Stage Coordinate System.
secondary = np.array([[610., 560., 0.],
[610., -560., 0.],
[390., -560., 0.],
[390., 560., 0.]])
# Pad the data with ones, so that our transformation can do translations too
def pad(x): return np.hstack([x, np.ones((x.shape[0], 1))])
def unpad(x): return x[:, :-1]
# This is the transform function. Pass Tray Coordinates to this.
def transform(x): return unpad(np.dot(pad(x), A))
X = pad(primary)
Y = pad(secondary)
# Solve the least squares problem X * A = Y
# to find our transformation matrix A
A, res, rank, s = np.linalg.lstsq(X, Y, rcond=None) # This is where the important work is done.
# Transforming a single point.
print('Transforming point (1, 2, 3) ...')
print(transform(np.array([[1, 2, 3]])))
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