minimum boundingbox of object

i wanna find minimum boundingbox that can fit in qr code . i searched and i diidn't know how to implement it pleade help

Answer 1

[Matt J]

load Image

BW=bwareafilt( imclose(~Image,ones(25))  ,1);

reg=regionprops(BW,'BoundingBox')

reg = struct with fields:
    BoundingBox: [428.5000 172.5000 322 321]

imshow(Image)
drawrectangle('Position',reg.BoundingBox,'Color','red');