This repository contains camera parameters (intrinsics and extrinsics) for Human3.6M dataset in handy format. File camera-parameters.json stores all parameters extracted from metadata.npy (see metadata.xml from official code package) using generate.py script.
- R - 3x3 rotation matrix
- t - 3x1 translation vector
- calibration_matrix - 3x3 calibration matrix
- distortion - 5 values [k1, k2, p1, p2, k3] (see this OpenCV article)
To build projection matrix P just multiply calibration and extrinsics matricies:
P = calibration_matrix @ np.hstack([R, t])
print(P.shape) # (3, 4)To project 3D point X to image plane:
X = np.random.rand(3) # random 3D point
X_homo = np.hstack([X, 1.0]) # convert to homogenous
x_homo = P @ X_homo # project
x = x_homo[:2] / x_homo[2] # convert back to cartesian (check that x_homo[2] > 0)