Questions tagged [yolo]

"You Only Look Once", a Deep Learning-based object recognition algorithm available in several different software implementations.

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Yolo Loss function explanation

I am trying to understand the Yolo v2 loss function: \begin{align} &\lambda_{coord} \sum_{i=0}^{S^2}\sum_{j=0}^B \mathbb{1}_{ij}^{obj}[(x_i-\hat{x}_i)^2 + (y_i-\hat{y}_i)^2 ] \\&+ \lambda_{...
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Yolo v3 loss function

The original loss function can be seen here and is more or less explained in Yolo Loss function explanation: \begin{align} &\lambda_{coord} \sum_{i=0}^{S^2}\sum_{j=0}^B \mathbb{1}_{ij}^{obj}[(x_i-...
1k views

On Yolo, and its loss function

I'm having a hard time understanding some on the inner-working of YOLO, especially the loss function depicted in this seminal paper. Bear in mind that I'm nowhere closed to being a specialist in deep ...
372 views

What is sigma function in the YOLO object detector?

I have gone through the YOLO9000 paper, in that they have mentioned that network predicts 5 coordinates of the bounding box, and from that we find the exact centre coordinates and the width and height....
745 views

Yolo loss function for detecting 1 class

I'm trying to work on a Yolo implementation which searches a 19x19 grid to find a specific item. There is only a single class in all of these images I am looking to get bounding boxes for. I'm a ...
1k views

I was going through the YOLO Object Detection Paper by Joseph Redmon. The authors use a grid size of $S = 7$. If I am not wrong, the network architecture has carefully been curated for this specific ...
907 views

YOLO loss function width and height component explanation

I am reading this paper on how yolo defines loss function. https://arxiv.org/abs/1506.02640 I did research on other posts, but these posts did not seem to answer my confusion: (How to calculate the ...
766 views

yolo cost function

At the output of the final layer of yolo, a leaky-relu is applied to the output, so if we have negative values for the width and height, the cost function will return a null value since we would have ...
2k views

How does the YOLO network create boundaries for object detection?

I'm not sure I understood how the YOLO network works. If you look at the description, https://pjreddie.com/darknet/yolo/, it appears to me that all is done thanks to convolution only. You end up with ...
762 views

Understanding the YOLO algorithm

I am trying to understand the logic behind object detection and the YOLO algorithm. I have read numerous blogs, tutorials, videos, papers, yet I am still not sure if I understood it correctly. Let's ...
1k views

How are YOLO anchor boxes generated?

I am recently trying out darkflow, a Tensorflow implementation of Darknet written by Joseph Redmon. Looking at the configuration files, I noticed a section called region as shown below. ...
644 views

What is the need of multiple Bounding Boxes per grid cell in YOLO v1?

This question is regarding YOLO v1 architecture as in here. I am confused as to why authors have used 2 bounding boxes per grid cell for training. Assuming there can be only one object per grid cell. ...
2k views

You Only Look Once (YOLO): Convolutional Neural Network

This question refers to the YOLO architecture (figure 3). In their architecture they define a convolutional layer 7x7x64-s-2 followed by a maxpool layer ...
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object detection loss function YOLO

as we know , in detection we have 2 loss : one is localization loss other is classification loss , in the formulation the 1th , 2th term related to localization loss and 3th term is related to ...
28 views

Performance of MaskRCNN/YOLO as a function of object size in pixels

I am trying to find references on how the resolution of an object affects the ability of object detection systems such as MaskRCNN and YOLO to correctly identify the object. For example, if the ...
2k views

YOLOv3 loss function

Follow-up to stats.stackexchange.com/questions/373266/yolo-v3-loss-function: In trying to finalize the development of my training labels and loss function I'm confused by the part in bold in the ...
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How to calculate the class probability of a grid cell in YOLO object detection algorithm?

I am going through the YOLO paper by Redmon, Divvala, Girshick & Farhadi (2015), "You Only Look Once: Unified, Real-Time Object Detection" (arXiV page here ) On the fourth page it mentions the ...
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Best way for robust hand tracking on PI 4

I need a robust hand tracking which should be running on a Raspberry Pi 4 model. Does anyone have some experience with that? One way could be to use OpenCV but I think it's just using the skin color ...
184 views

The reason for multiple bounding boxes use for each grid cell - YOLO

I'm not quite sure what is the main reason why YOLO uses multiple bounding boxes for a grid cell. An answer I can find on web is for multiple aspect ratio in the prediction. However I donāt think itās ...
276 views

Is YOLO a good algorithm for defect detection on images?

I wish to train an algorithm to detect defects on images of labels. These may be such things as scratches, tears and voids. I would like to try to train a YOLO algorithm to do this, but it is very ...
717 views

what purpose do the grid cells serve in YOLO object detection algorithm?

so I was looking at YOLO and I read several blogs online, but one concept I'm having trouble understanding is why do we want to divide the image into different grids, and then predict the bounding box ...
57 views

Yolov3: Single-class vs multiple class

I'm really new to object detection with Yolov3. Let's say I have 10 classes and the amount of data is approximately the same. Do I achieve better average precision when I use 10 Yolo models and train ...
30 views

Retraining of object detection CNN

I am working on an object detection system that should detect UI elements (such as button, checkbox, radio button, etc..) in the photo of a touch screen of printer (not screenshots, but literally a ...
39 views

What is the purpose of grids in YOLO?

Considering the YOLO algorithm. Assume: Input image is n x n x 3 Number of anchor boxes is m For each anchor box, we have 1 (pc = probability of object) + 4 (4 variables to predict the bounding ...
30 views

How exactly the midpoint of the object is selected in YOLO algorithm?

The boundaries of the object are encoded into 4 scalars: Bx, By, Bh, Bw. Bh and Bw are calculated using the ratio of the width of the bounding box to the width of the relative grid cell. But I can't ...
245 views

Change hyperparameter of YOLOv3 for face detection

I have tried with some github implementation on YOLOv3 in tensorflow. I trained yolov3 for faces with WIDER face dataset, I haven't changed the original configuration of YOLOv3. After training the ...
25 views

Impact of increasing number of classes on object detection rate/speed

I am trying to build a Darknet (C++) model to detect custom objects. Initially, in the testing phase for 50 objects with tiny yolo, I am getting 35 FPS speed. If I increase the number of objects to ...
42 views

YOLO architecture clarifications

I am trying to train a YOLO model to draw bounding boxes around individual handwritten words. I don't need the network to classify them and I don't need the words to be in order either. I would have ...
71 views

What YOLO architecture should I use for handwriting detection?

I want to create a cnn to draw bounding boxes around individual handwritten words. Ideally I would input a picture of a filled piece of notebook paper and get a cropped image of each word (they don't ...
13 views

Passing specific achors to YoLo training process

We are trying to improve our YoLo algorithm results of recognizing one class of varying sizes (~ varying distance to the camera). Luckily, the a priori position of the object is known with a certain ...
26 views

YOLOv3 Detection Layer

I'm learning about YOLOv3 and wanted to confirm my understanding of how the detection layer works. Just to confirm, we have some output tensor from which we would filter for the objectness score above ...
I am dealing with Yolo Loss Function (the following). \begin{align} &\lambda_{coord} \sum_{i=0}^{S^2}\sum_{j=0}^B \mathbb{1}_{ij}^{obj}[(x_i-\hat{x}_i)^2 + (y_i-\hat{y}_i)^2 ] \\&+ \lambda_{...