square elongation for cropmodel

[bw4sz]

From an unpublished paper, which I can later link.

Instead of cropping tightly around the object, we
convert the bounding boxes into square shapes by extending the shorter side to match the length of the longer side.
Another way to think of it is that we are doing padding
with natural pixels. Our box expansion approach maintains
the original aspect ratios of objects without introducing artifacts, reducing the likelihood of misidentification.

We could do this for the cropmodel workflow.

The relevant code is here:

DeepForest/deepforest/model.py

Line 161 in 8815d4b

xmin, ymin, xmax, ymax = box

[ethanwhite]

This is a really cool idea!

[NaganathanM]

Hi! If my understanding is correct, you want to adjust the xmin, xmax or ymin, ymax depending on the longer side, to make the box square. Shall I take up and work on this if it's still open?

[bw4sz]

For sure, let me know if you need help.

[NaganathanM]

Hello! Sorry I took long time. So, I've implemented a function that takes boxes - a list of coordinates and return the adjusted coordinates. Here, if length on x-axis is longer, then length on y-axis is adjusted, keeping the ymin the same. Similarly, xmin is kept the same and x-axis length is elongated if y-axis length is longer. Go through the code and give me your feedback:

def square_bounding_box(boxes):
    """
    The square_bounding_box function takes a list of x and y coordniates as arguments from the 'boxes' liat; calculates the longer side,
    and adjust the shorter side such that both lengths are equal to form a square, and return the coordniates
    boxes (list): A list of bounding box coordinates in the format [xmin, ymin, xmax, ymax]
    """
    if abs(boxes[1])-abs(boxes[0]) > abs(boxes[3])-abs(boxes[2]):
        boxes[3] = boxes[2] + abs(boxes[1])-abs(boxes[0])
    if abs(boxes[3])-abs(boxes[2]) > abs(boxes[1])-abs(boxes[0]):  
        boxes[1] = boxes[0] +  abs(boxes[3])-abs(boxes[2])         
        
    return boxes

#help(square_bounding_box)
if __name__ == "__main__":
    print(square_bounding_box([3,8,4,7]))
    print(square_bounding_box([6,9,2,9]))

[bw4sz]

good start, cleaning up code readability

def square_bounding_box(boxes: list) -> list:
    """
    Adjusts the bounding box coordinates to form a square.

    Args:
        boxes (list): A list of bounding box coordinates in the format [xmin, ymin, xmax, ymax]

    Returns:
        list: Adjusted bounding box coordinates to form a square
    """
    xmin, ymin, xmax, ymax = boxes

    width = xmax - xmin
    height = ymax - ymin

    if width > height:
        # Adjust height to match width
        ymax = ymin + width
    elif height > width:
        # Adjust width to match height
        xmax = xmin + height

    return [xmin, ymin, xmax, ymax]

if __name__ == "__main__":
    print(square_bounding_box([3, 8, 4, 7]))  # Example 1
    print(square_bounding_box([6, 9, 2, 9]))  # Example 2