How to get bbox from segmentation?

[chiboreache]

i've tried

                        xy_max = max(xy_ls)
                        xy_min = min(xy_ls)
                        h, w = np.subtract(xy_max, xy_min)

but sometimes i get results below zero

[chiboreache]

            px = [a[0] for a in anno['points']]
            py = [a[1] for a in anno['points']]
            obj = {
                "bbox": [np.min(px), np.min(py), np.max(px), np.max(py)],