Get a point cloud corresponding to given pixel indices

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Hi, I'm trying to publish a point cloud which corresponds to given pixel indices.

I'm using Realsense camera so will use similar terminology.

1. I have certain indices of a color image, namely, Nx2 array indices where indices[i, :] = [i, j] for the pixel (i, j).
2. I subscribe a depth image aligned to color image, namely, alinged_depth.
3. I wanna get a point cloud (both PointCloud2 and PointCloud) which corresponds to the given indices, indices.

Is there any workaround for this?