Share Your Experience: Take the 2024 Developer Survey

# Tag Info

Accepted

### What's the role of bounding boxes in object detection?

A bounding box is a rectangle superimposed over an image within which all important features of a particular object is expected to reside. It's purpose is to reduce the range of search for those ...
• 7,513
Accepted

### How are IOUs for ground truth boxes in YOLO calculated?

My assumption was correct: the ground truth bounding box is aligned with an anchor box such that they share the same center In other words, only the widths and heights are used to calculate the ...
• 73

### YOLO - are the anchor boxes used only in training?

Object detection models behave the same during both, training and test phase, i.e. they just return thousands and thousands of bounding boxes as predictions, plus a confidence score for each box (...
• 5,308
Accepted

### How does a bounding box detection network "know" about absolute position?

It of course depends on the detection model that is used. But in your case I think you relate to a Faster-RCNN type architecture for bounding box detection. In this case only the relative position to ...
1 vote

### Can the output of non-max suppression have more bounding boxes than the number of objects the picture actually has?

Usually bounding-boxes are associated to a score or confidence. So, you loop over them considering the highest scoring first. You then set a threshold on the IoU (intersection over union) that is used ...
• 2,948
1 vote
Accepted

### Why is it called "area of union" when calculating the Intersection over Union?

Consider these two sets $A = \{1, 2, 3, 4 \}$ and $B = \{0, 2, 3, 5, 6 \}$. Their union $A \cup B = \{0, 1, 2, 3, 4, 5, 6\}$. So, $|A \cup B| = 7$. The order of these numbers in $A \cup B$ does not ...
• 40.8k
1 vote

### How to architect a network to find bounding boxes in simple images?

There are some special architectures of CNNs which are designed exactly for the task you mention. The Detector library includes a collection of these architectures, this paper describes the Mask R-CNN ...
• 225
1 vote
Accepted

### Why do the object detection networks produce multiple anchor boxes per location?

Yes, theoretically it is possible to learn the offsets to get any possible bounding box from only one anchor box. However, it is hard to learn such dramatic shifts and changes. Learning only small ...
1 vote

### Can bounding boxes further improve the performance of a CNN classifier?

Information outside of the bounding box could still be useful as context. So not to lose it you can but bounding box as pixel mask into additional "pseudo-color" layer. That way you can also have ...
• 725

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