Converting bounding boxes from labels.json file to pixel values

Question

How can I convert the bounding boxes from a labels.json file to pixel values? The file follows the schema at "https://schema.cognitiveservices.azure.com/formrecognizer/2021-03-01/labels.json". Here is an example bounding box from the file:

{
    "page": 1,
    "text": "1AJ",
    "boundingBoxes": [
        [
            0.6822429906542056,
            0.07027328499721137,
            0.6919951239333604,
            0.06748466257668712,
            0.6924014628199918,
            0.08087005019520357,
            0.6822429906542056,
            0.08198549916341327
        ]
    ]
}

I need to convert these bounding boxes to pixel values. Can you provide any guidance or resources on how to do this?

Answer 1

Hi @Yves Guena ,

Thank you for using Microsoft Q&A. Form Recognizer does not have an inbuilt function to convert bounding boxes from a labels.json file to pixel values. However, you can use the formula pixel_value = bounding_box_value * image_size to calculate the pixel values for the bounding boxes.For example, if the image size is 1000x1000 pixels and the bounding box value is [0.6822429906542056,0.07027328499721137], you can calculate the pixel values as follows:

x1 = 0.6822429906542056 * 1000 = 682.2429906542056
y1 = 0.07027328499721137 * 1000 = 70.27328499721137

To use this formula, you need to know the size of the image in pixels and the normalized coordinates for the bounding boxes from the labels.json file.

You can then use the formula to calculate the pixel values for the bounding boxes. Hope this helps.

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