Random Crop yields incorrect value for bounding box

🐛 Bug

The bbox_random_crop function does not produce a reasonable result. Consider the following snippet of code.

To Reproduce

from albumentations import functional as F
bbox = (0.129, 0.7846, 0.1626, 0.818)
cropped_bbox = F.bbox_random_crop(bbox=bbox, crop_height=100, crop_width=100, h_start=0.7846, w_start=0.12933, rows=1500, cols=1500)
cropped_bbox
(0.125, 0.788999, 0.629, 1.29)
#Notice y2 is outside of crop range.
#But the following assert passes
assert bbox[3] < (100/1500) + 0.7846
#Fails
assert all([(y >= 0) & (y<=1) for y in list(cropped_bbox)])

Expected behavior

A augmented bbox that is fully within the image crop. The crop_height plus the start of the crop is larger than the y2 of the bounding box, but 1.29 coordinate in the cropped box suggestion it is outside of the crop area.

Environment

• Albumentations version (e.g., 0.1.8): 0.5.2
• Python version (e.g., 3.7): 3.7
• OS (e.g., Linux): OSX
• How you installed albumentations (conda, pip, source): pip
• Any other relevant information:

Additional context

I am making a custom augmentation to Zoom in on a given bounding box. CropSafe (but not all boxes). Is there syntax that i’m misunderstanding, it doesn’t feel like this could be the case. Dtype issue?

[Dimfred]

So I fixed the errors for me by changing the conversion in bbox_utils for the yolo case. Since yolo comes in already relative a conversion to absolute format and then back to relative will yield errors.

So instead of convertig to absolute I removed it and now with the coordinates I get from yolo

x, y, w, h = yolo_bbox

w_half, h_half = w / 2, h / 2
x_min, x_max = x - w_half, x + w_half
y_min, y_max = y - h_half, y + h_half

and vice versa in the from_albumentation case.

[Dimfred]

@veve90 https://github.com/albumentations-team/albumentations/pull/924/commits/bae5414239c50f04e50736768e027f02e61f053c#diff-78866cc64c23c9e242bdcb84933e35a5218dda5b971f3f3d9f8348d5af855cd0R233