select blue as background and invert.
just “blindly” mask away the QR codes on the side. they’re always there, never near the object. define a rectangle covering them, erase that area in the mask.
don’t get your hopes up. picture is blurry, so you’ll get blue bleeding into the object, or the object getting thinner than it is.
the bluescreen isn’t terribly uniform. the more variation it has, the wider the range you have to select, which may take away from color ranges found in the foreground.
if you’re careful with everything, this blur could be dealt with and turned into grayscale transparency information (rather than a hard binary mask). still, the whole process benefits from high resolution and the object being in focus.
the object, the roots, are illuminated by the bluescreen, which is bad. bluescreen must be far enough away that they throw no light onto the foreground. or very little, which can be “drowned out” by illumination on the foreground/object.