How can I convert image array data to PointCloud2?

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I have special image array data and I want convert it to PointCloud2.

But I can't understand meaning of PointCloud2's parameter, so I can't do converting.

Every pixel of Image array data have straight distance in the floor and have the angle from the center of bottom. ( angle and distance in real world)

This is my questions.

1. What is point_step, row_step, height, width in PointCloud2,msg?

2. What is offset and count in PointField.msg?

3. How cant I convert image array data to PointCloud2?