Unable to serialize vpi.warp type object in python 3 using json, pickle and marshal - Vision Programming Interface, Jetson

Autonomous Machines Jetson & Embedded Systems Jetson Xavier NX
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1

Hi,

I tried serializing vpi.warpmap object using json.dumps(), pickle.dumps() and marshal.dumps() methods. However, I am getting the error - ‘Object of type WarpMap is not JSON serializable’.
Are VPI objects serializable? My end goal is to store the warpmap in a file and retrieve it later.
Can you kindly help.

Thanks

3

Hi,

VPI doesn’t support serialization currently.
Please convert it into other formats, ex numpy, first.

Thanks.

4

Thank you for the reply. I am able to convert a vpi.warpmap object to numpy array. However, I am unable to convert numpy array back to a vpi.warpmap object. My end goal is to use this warpmap in vpi.remap function for distortion correction.

Thanks

5

Hi,

You can manually serialize the parameter.
For example:

Serialize

# Create an uniform grid
grid = vpi.WarpGrid(imgSize)

# Create undistort warp map from the calibration parameters and the grid
undist_map = vpi.WarpMap.fisheye_correction(grid,
                                            K=camMatrix[0:2,:], X=np.eye(3,4), coeffs=coeffs,
                                            mapping=vpi.FisheyeMapping.EQUIDISTANT)

import pickle
with open('warpMap.pickle', 'wb') as f:
    pickle.dump([imgSize,camMatrix[0:2,:],np.eye(3,4),coeffs,vpi.FisheyeMapping.EQUIDISTANT], f)

Deserialize

with open('warpMap.pickle', 'rb') as f:
    [size,K,X,coeffs,mapping] = pickle.load(f)

grid = vpi.WarpGrid(size)

# Create undistort warp map from the calibration parameters and the grid
undist_map = vpi.WarpMap.fisheye_correction(grid, K=K, X=X, coeffs=coeffs, mapping=mapping)

Thanks.