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fixed quaternion method from_dcm()

This commit is contained in:
tumbili 2015-02-23 22:26:41 +01:00
parent 41377709e6
commit a252f4a991
1 changed files with 28 additions and 6 deletions
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34
src/lib/mathlib/math/Quaternion.hpp
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@ -135,12 +135,34 @@ public:
data[3] = static_cast<float>(cosPhi_2 * cosTheta_2 * sinPsi_2 - sinPhi_2 * sinTheta_2 * cosPsi_2);
}
void from_dcm(const Matrix<3, 3> &m) {
// avoiding singularities by not using division equations
data[0] = 0.5f * sqrtf(1.0f + m.data[0][0] + m.data[1][1] + m.data[2][2]);
data[1] = 0.5f * sqrtf(1.0f + m.data[0][0] - m.data[1][1] - m.data[2][2]);
data[2] = 0.5f * sqrtf(1.0f - m.data[0][0] + m.data[1][1] - m.data[2][2]);
data[3] = 0.5f * sqrtf(1.0f - m.data[0][0] - m.data[1][1] + m.data[2][2]);
void from_dcm(const Matrix<3, 3> &dcm) {
float tr = dcm.data[0][0] + dcm.data[1][1] + dcm.data[2][2];
if (tr > 0.0f) {
float s = sqrtf(tr + 1.0f);
data[0] = s * 0.5f;
s = 0.5f / s;
data[1] = (dcm.data[2][1] - dcm.data[1][2]) * s;
data[2] = (dcm.data[0][2] - dcm.data[2][0]) * s;
data[3] = (dcm.data[1][0] - dcm.data[0][1]) * s;
} else {
/* Find maximum diagonal element in dcm
* store index in dcm_i */
int dcm_i = 0;
for (int i = 1; i < 3; i++) {
if (dcm.data[i][i] > dcm.data[dcm_i][dcm_i]) {
dcm_i = i;
}
}
int dcm_j = (dcm_i + 1) % 3;
int dcm_k = (dcm_i + 2) % 3;
float s = sqrtf((dcm.data[dcm_i][dcm_i] - dcm.data[dcm_j][dcm_j] -
dcm.data[dcm_k][dcm_k]) + 1.0f);
data[dcm_i + 1] = s * 0.5f;
s = 0.5f / s;
data[dcm_j + 1] = (dcm.data[dcm_i][dcm_j] + dcm.data[dcm_j][dcm_i]) * s;
data[dcm_k + 1] = (dcm.data[dcm_k][dcm_i] + dcm.data[dcm_i][dcm_k]) * s;
data[0] = (dcm.data[dcm_k][dcm_j] - dcm.data[dcm_j][dcm_k]) * s;
}
}
/**