Thank you for reaching out to us. I think you have questions about the value of boundingBoxes, below I will give an example to explain:
'boundingBox': [ 57.1, 683.3, 100.2, 683.3, 100.2, 673.3, 57.1, 673.3 ]
Those values represent the vertices of the bounding box as below:
(57.1,683.3) X1,Y1---->x2,y2(100.2,683.3) | | | | (57.1,673.3) X4,Y4<----x3,y3(100.2,673.3)
All the boundingBoxes for the same part of form should be the same, it shows the vertices of the target content.
If you want to measure the boundingBoxes, you can use above vertices to do the calculation.
Hope this helps!
-Please kindly accept the answer if you feel helpful, thanks!