Questions tagged [computer-vision]

For questions related to computer vision, which is an interdisciplinary scientific field (which can e.g. use image processing techniques) that deals with how computers can be made to gain high-level understanding from digital images or videos. For example, image recognition (that is, the identification of the type of objects in an image) is a computer vision problem.

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47 views

Is there an efficient way of determining the layers with the best performance as feature extractors in GoogleNet?

I am using a caffe model of pre-trained GoogleNet trained on ImageNet from here for image retrieval task (place recognition, more specifically). I would like to know the layer with best performance ...
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2answers
182 views

Why is the validation performance better than the training performance?

I am training a classifier to identify 24 hand signs of American Sign Language. I created a custom dataset by recording videos in different backgrounds for each of the signs and later converted the ...
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1answer
93 views

In Fast R-CNN, how are input RoIs mapped to the respective RoIs in the feature map before RoI pooling?

I've been reading the Fast R-CNN paper. My understanding is that the input to one forward pass is the whole input image plus a list of RoIs (generated by selective search or another region proposal ...
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24 views

Train an AI to infer accurate mathematical calculations by simply “looking” at images of shapes/objects

I’d like to build a model that has an understanding of geometry, where it can be applied to question and answering system. Specifically, it would be nice if it could determine the volume of an object ...
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29 views

Suitable algorithms for classifying terrain condition (asphalt, dirt etc) for motor vehicles

I am required to obtain data through a sensor located on the vehicle reading speed, vibration, roll and tilt, within a sample time, to classify the current road condition using machine learning for a ...
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78 views

Intuition behind single-shot object detection

Is there a good way to understand how single-shot object detection works? The most basic way to do detection is use a sliding-window detector and look at the output of the NN to detect if a class is ...
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2answers
697 views

What are the reasons behind slow YOLO training?

I'm testing out YOLOv3 using the 'darknet' binary, and custom config. It trains rather slow. My testing out is only with 1 image, 1 class, and using YOLOv3-tiny instead of YOLOv3 full, but the ...
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1answer
100 views

YOLOv3 Model Structure: Why is filters = (classes + coords + 1) * num?

Here's a tutorial about doing custom training of YOLO (Darknet): https://medium.com/@manivannan_data/how-to-train-yolov3-to-detect-custom-objects-ccbcafeb13d2 The tutorial guides how to set values in ...
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3answers
166 views

Does a fully convolutional network share the same translation invariance properties we get from networks that use max-pooling?

Does a fully convolutional network share the same translation invariance properties we get from networks that use max-pooling? If not, why do they perform as well as networks which use max-pooling?
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69 views

Weird border artifacts when training a CNN

I've been trying to use this DeepLabv3+ implementation with my dataset (~1000 annotated images of the same box, out of the same video sequence): https://github.com/srihari-humbarwadi/...
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82 views

What are the pros and cons of Keras, PyTorch and Caffe for computer vision?

I have tried to get the basic grasp of the following deep learning frameworks with python: Keras Pytorch Caffe However, I have lately noticed that people in the computer vision community care less ...
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1answer
115 views

What is the difference between exhaustive nearest neighbor search and k-nearest neighbour search?

I have two lists of feature vectors calculated from pre-trained CNN for image retrieval task: Query: FV_Q and Reference FV_R. <...
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1answer
43 views

Does the bag-of-visual-words method improve the classification accuracy?

I'm a beginner in computer vision. I want to know which option among the following two can get better accuracy of image classification. SIFT features + SVM Bag-of-visual-words features + SVM Here's ...
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25 views

What are the current tools and techniques for image segmentation in order of pragmatism?

To explain what I mean I'll depict the two extremes and something in the middle. 1) Most pragmatic: If you need to just segment a few images for a design project, forget AI. Go into Adobe Photoshop ...
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1answer
34 views

Interpolating image to increase resolution before feeding it to a neural network

Interpolation is a common way to make an image fit the right input shape for a neural network. But is there any point in using interpolation to make it easier for the network to learn? I assume ...
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14 views

How can a new metric applied for humans causing danger on railtracks?

I am writing myself and was thinking about, what kind of metric can be applied to measure the "dangerousness" of a human being on a railtrack? For example detecting if a human is running on the rails? ...
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1answer
791 views

How feasible is it to perform pose estimation on a Raspberry Pi 4 using a Pi-Cam?

I want to estimate hand poses and recognize gestures using an open-source library like OpenPose on live video. Considering the fact that such libraries are very computationally intensive. How likely ...
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29 views

What's the best solution to find distance of an object to camera?

I have an object with known size and I want to know that's the distance from the camera and camera angle. Is there any way to do this? I have a single source (camera).
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27 views

State of the art in voice recognition

In the media there's lot of talk about face recognition, mainly with respect to identifying faces (= assigning to persons). Less attention is paid to the recognition of facially expressed emotions but ...
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1answer
254 views

Which deep learning models are suitable for image-to-image mapping?

I am working on a problem in which I need to train a neural network to map one or more input images to one or more output images (1 channel for image). Below I report some examples of input&output....
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26 views

Scoring feature vector with Support Vector Machine

I am reading the R-CNN paper by Ross Girshick1 et al. (link) and I fail to understand how they do the inference. This is described in the section 2.2.Test-time Detection in the paper. I quote: At ...
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1answer
367 views

How does non-max suppression work when one or multiple bounding boxes are predicted for the same object?

My understanding of how non-max suppression works is that it suppresses all overlapping boxes that have a Jaccard overlap smaller than a threshold (e.g. 0.5). The boxes to be considered are on a ...
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1answer
256 views

When training a CNN, what are the hyperparameters to tune first?

I am training a convolutional neural network for object detection. Apart from the learning rate, what are the other hyperparameters that I should tune? And in what order of importance? Besides, I read ...
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3answers
175 views

If I trained a model to perform semantic segmentation on images with only one object, would it also work on images with multiple objects?

I'm working on semantic segmentation tasks in the medical space using the U-Net. Let's say that I train a U-Net model on medical images with the goal of segmenting out, say, ligaments, from a medical ...
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1answer
2k views

What is a cascaded convolutional neural network?

For a project I am doing, I found the paper Face Alignment in Full Pose Range: A 3D Total Solution. It is using a cascaded convolutional neural network, but I wasn't able to find the original paper ...
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81 views

Rendering images and voxelizing the images

I am using the shapenet dataset. From this dataset, I have 3d models in .obj format. I rendered the images of these 3d models using pyrender library which gives me an image like this : Now I am using ...
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2answers
110 views

What is the reasoning behind the number of filters in the convolution layer?

Let's assume an extreme case in which the kernel of the convolution layer takes only values 0 or 1. To capture all possible patterns in input of $C$ number of channels, we need $2^{C*K_H*K_W}$ filters,...
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0answers
22 views

Can an image recognition model used for human pose estimation?

I am currently writing my thesis about human pose estimation and wanted to use Google's inception network, modify it for my needs and use transfer learning to detect human key joints. I wanted to ask ...
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334 views

Find the nearest object in a image which is captured from camera?

Objective : To find the nearest object (closer distance object) in the single camera image. But Image Contains multiple objects shown below: I searched in the net and found this formula to ...
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0answers
29 views

SLAM versus "STAM" in vision

In the paper 'Visual SLAM algorithms: a survey from $2010$ to $2016$' by Takafumi Taketomi, Hideaki Uchiyama and Sei Ikeda it is mentioned 'It should be noted that tracking and mapping (TAM) is used ...
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34 views

What is the difference between principal component analysis and singular value decomposition in image processing?

What is the difference between principal component analysis and singular value decomposition in image processing? Which one performs better, and why?
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1answer
265 views

Which AI methods are most appropriate for login face recognition?

I want to make a face authentication application. I need to approve the face during the login based on whether the registered face and the login face match. Which are the possible appropriate AI ...
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0answers
49 views

If you have a very distorted image, would affine transformations applied to images make object detection algorithms make more mistakes?

If you have a very distorted video/image, would affine transformations of the images make object detection algorithms make more mistakes compared to a normal camera?
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28 views

Ghost camera or video overlays for example in sports

Secondary camera, ghost overlay, video merge... I do not know if what I mean has a more specific name. I wonder if this is a thing. This could be insightful for example in racing sports where ...
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1answer
72 views

How to draw bounding boxes for gender classification?

I wonder what is the better way of drawing rectangles on images for gender classification. My task is to create a classifier (CNN based) to detect gender from pictures of entire bodies (not just faces)...
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0answers
48 views

How can I avoid displaying the velocity in the updated tracklets?

In target tracking, the dimensions of objects change, especially if they are detected using a LIDAR sensor. Also, the static objects in consecutive frames are not 100% static, their position changes a ...
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1answer
163 views

What is "temporal depth"?

I need some explanation about the following paragraph (page 3) from the paper A Novel Approach for Robust Multi Human Action Detection and Recognition based on 3-Dimentional Convolutional Neural ...
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2answers
97 views

Are there ensemble methods for regression?

I have heard of ensemble methods, such as XGBoost, for binary or categorical machine learning models. However, does this exist for regression? If so, how are the weights for each model in the process ...
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0answers
22 views

Do backgroundSubtractor functions in opencv only detect moving objects?

There are some backgroundsubtractor functions in opencv like backgroundsubtractormog2 , backgroundsubtractorGMG and ... . It seems that these functions only detect moving objects in a video. But I ...
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33 views

Are there free and easy-to-use annotation tools for 3D bounding boxes? [closed]

Are there free and easy-to-use annotation tools for 3D bounding boxes? There is a lot of annotation tools out there, but most of them only good for 2d boxes.
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1answer
298 views

How can I detect moving objects in a video by OpenCV without using deep learning techniques?

I want to detect moving objects in a surveillance video without using machine learning tools (like neural networks). Is there a simple way in the OpenCV library? What is an efficient solution for this ...
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0answers
14 views

Can Grad CAM feature maps be used for Training?

I am trying to recreate the architecture of the following paper: https://arxiv.org/pdf/1807.03058.pdf Can someone help me in explaining how are the feature maps coming out of the output of GradCam ...
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0answers
2k views

How many training data required for GAN?

I'm beginning to study and implement GAN to generate more dataset. I'll just try to experiment with state-of-the-art GAN models as described in here https://paperswithcode.com/sota/image-generation-on-...
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1answer
30 views

Size of image input of neural networks while resizing may not be appropriate

I have the following problem while using convolutional neural networks to detect forgeries: Resizing the image to fit the required input size may not be a good way because the forgery detection ...
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0answers
37 views

How can I improve the performance of a model trained to detect vehicle poses?

I'm looking for some suggestions on how to improve our vehicle image recognition. We have an online marketplace where customers submit photos of their vehicles. The photos need to meet certain ...
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1answer
33 views

If an image contains two distinct objects, should I create a copy of this image with distinct labels for each copy?

Suppose we want to detect whether an object is one of the following classes: $\text{Object}_1, \text{Object}_2, \text{Object}_3$ and $\text{Person}$. Should the annotated images only contain bounding ...
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39 views

How to measure object size from the disparity map using CNN?

I am a student learning about image processing using CNN. I want to learn how to measure the object size from the disparity map obtained from left and right stereo images.
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1answer
67 views

How to calculate the size of a 3d object from an image?

I am wondering how to calculate the size of a 3d object in an image without knowing the focal length of the camera but the distance from the camera to the object.
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0answers
171 views

Is there a dataset for the detection of bomb explosions? [closed]

I would like to train a deep neural network to recognize bomb explosions. I was wondering if there is an open visual dataset for bomb explosion? Alternatively, if you know a good deep architecture or ...
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0answers
51 views

Ideas on a network that can translate image differences into motor commands?

I'd like to design a network that gets two images (an image under construction, and an ideal image), and has to come up with an action vector for a simple motor command which would augment the image ...

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