Set camera intrinsic parameter

Hello,

I am currently using Isaac Sim to generate images with the same camera intrinsics as my realsense D435i camera. The camera intrinsic matrix is [606.86, 0, 321.847; 0, 606.86, 244.995; 0, 0, 1] and the image resolution is 640 * 480. Is is possible to generate images with optical center no exactly in the middle? I have tried to change the get_projection_matrix function in the helpers.py in omni.syntheticdata module, but it doesn’t seems to work.

def get_projection_matrix(fov, aspect_ratio, z_near, z_far):
“”"
Calculate the camera projection matrix.

``````Args:
fov (float): Field of View (in radians)
aspect_ratio (float): Image aspect ratio (Width / Height)
z_near (float): distance to near clipping plane
z_far (float): distance to far clipping plane

Returns:
(numpy.ndarray): View projection matrix with shape `(4, 4)`
"""
a = -1.0 / math.tan(fov / 2)
b = -a * aspect_ratio
c = z_far / (z_far - z_near)
d = z_near * z_far / (z_far - z_near)
offset_x = 1.847  #value addition to the x axis (positive)
offset_y = 4.995  #value addition to the y axis (positive)
tx = (offset_x * 2) / 640
ty = (offset_y * 2) / 480
tf = np.array([[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 1, 0], [tx, ty, 0, 1]])
projection_matrix = np.dot(np.array([[a, 0.0, 0.0, 0.0], [0.0, b, 0.0, 0.0], [0.0, 0.0, c, 1.0], [0.0, 0.0, d, 0.0]]), tf)
return projection_matrix
#np.array([[a, 0.0, 0.0, 0.0], [0.0, b, 0.0, 0.0], [0.0, 0.0, c, 1.0], [0.0, 0.0, d, 0.0]])``````

@shengyu952014 You will have to update the USD camera property to generate your expected image from the renderer. `get_projection_matrix` returns the camera projection matrix based on the USD camera property values.

One thing to note in the image below is that Horizontal Aperture Offset and Vertical Aperture Offset are not implemented and hence updating their value might not impact the rendered image.