Why are negative coordinates disallowed in BBox2D setters?

[varunagrawal]

Why are negative coordinates disallowed in BBox2D setters?

[varunagrawal]

Ah good catches. It doesn't make sense to have negative values for x/y values (or does it?) since you would want to clamp that to [0, H/W) for it to be meaningful for any object detection system.

I can definitely fix the constructor to put in the required checks though. Would you have any thoughts on whether allowing negative x/y values would make sense?

[varunagrawal]

Also, word of caution, currently the way I compute x2 is x2 = x1+w-1, but after talking to detection experts, they all agree that the 1-offset should be a non-artifact and x2 should be computed as x2 = x1 + w.

I am going to thus change the API behavior in the near future (hence why this project is still in beta!) and publish a v1 once I see things follow the modern practices regarding bounding boxes.

[gmyers18]

From my perspective allowing negative coordinates will allow the library to be more flexible as a means for generically describing a region of interest with a bounding box.

I think the need to clip to scene/image bounds is a very common use case with bounding boxes, but it is ultimately application dependent. But other applications might be interested in maintaining state for regions that are fully or partially out of scene, where there is information that you don't want to lose in the fact that something is (partially) out of scene. The application itself would then need to handle any sort of clipping downstream if it needs things to be fully in-bounds for visualization, etc.

[gmyers18]

Thanks for the head's up. I think the -1 offset is a fairly common point of disagreement when it comes to bounding boxes. FWIW I think the way you have it currently with the -1 is correct, but I have certainly seen it the other way too.

[varunagrawal]

I can't argue against your point for negative values. Thank you for the feedback, since this will definitely make bbox more flexible.

[varunagrawal]

I have updated the package to allow BBox2D to accept negative values. New version is 0.9.1.

[gmyers18]

Looks great. Thanks!