Deep Learning for 3D Point Clouds, volume detection and meshing - deep-learning

I'm working on an archaeological excavation point cloud dataset with over 2.5 Billion points. This points come from a trench, a cube 10 x 10 x 3 m. Each point cloud is a layer, the gaps between are the excavated volumes. There are 444 volumes from this trench, 700 individual point clouds.
Can anyone give me some direction to any algorithms which can mesh these empty spaces? I'm already doing this semi-automatically using Open3D and other python libraries, but if we could train the program to assess all the point clouds and deduce the volumes it would save us a lot of time and hopefully get better results.

Related

Image Classification on heavy occluded and background camouflage

I am doing a project on image classification on classifying various species of bamboos.
The problems on Kaggle are pretty well labeled, singluar and concise pictures.
But the issue with bamboo is they appear in a cluster in most images sometimes with more than 1 species. Also there is a prevalence of heavy occlusion and background camouflage.
Besides there is not much training data available for this problem.
So I have been making my own dataset by collecting the data from the internet and also clicking images from my DSLR.
My first approach was to use a weighted Mask RCNN for instance segmentation and then classifying it using VGGNet and GoogleNet.
My next approach is to test on Attention UNet, YOLO v3 and a new paper BCNet from ICLR 2021.
And then classify on ResNext, GoogleNet and SENet then compare the results.
Any tips or better approach is much appreciated.

6D pose estimation of a known 3D CAD object with limited model training for a new object

I'm working on a project where I need to estimate the 6DOF pose of a known 3D CAD object in a single RGB image - i.e. this task: https://paperswithcode.com/task/6d-pose-estimation. There are several constraints on the problem:
Usable commercially (licensed under BSD, MIT, BOOST, etc.), not GPL.
The CAD object is known and we do NOT aim for generality (i.e.recognize the class of all chairs).
The CAD object can be uploaded by a user, so it may have symmetries and a range of textures.
Inference step will be run on a smartphone, and should be able to run at >30fps.
The inference step can either be a) find the pose of the object once and then I can write code to continue to track it or b) find the pose of the object continuously. I.e. the model doesn't need to have any continuous refinement steps after the initial pose estimate is found.
Can be anywhere on the scale of single instance of a single object to multiple instances of multiple objects (MiMo). MiMO is preferred, but not required.
If a deep learning approach is used, the training time required for a new CAD object should be on the order of hours, not days.
Can either 1) just find the initial pose of an object and not have any refinement steps after or 2) find the initial pose of the object and also have refinement steps after.
I am open to traditional approaches (i.e. 2D->3D correspondences then solving with PnP), but it seems like deep learning approaches outperform them (classical are too slow - Real time 6D pose estimation of known 3D CAD objects from a single 2D image or point clouds from RGBD Camera when objects are one on top of the other?). Looking at deep learning approaches (poseCNN, HybridPose, Pix2Pose, CosyPose), it seems most of them match these constraints, except that they require model training time. Though perhaps I can use a single pre-trained model and then specialize it for each new CAD object with a shorter training step. But I am not sure of this, and I think success probably relies on the specific model chosen. For example, this project says it requires 3 hours of training time: https://github.com/DLR-RM/AugmentedAutoencoder.
So, my question: would somebody know what the state of the art, commercially usable implementation that doesn't require extensive training time for a new CAD object is?

Deep Q Learning : How to visualize convergence?

I have trained an RL agent in an environment similar to the Puckworld. Theres no puck though! The agent is in continuous space and wants to reach a fixed target. Each episode the agent is born at a random location and there is an added noise to each action to make learning less trivial.
The reward is given every step as a scaled version of the distance to the target.
I want to plot the convergence of the neural network. The same problem in discrete space and using Q learning, I would plot the sum of all elements in Q matrix vs episode number. This gave me a good understanding of the performance of the network. How can i do the same for a neural network?
Plotting the reward collected in an episode vs episode number is not optimal here.
I use PyTorch. Any help is appreciated

CNN,neural network angle detection

I have a dataset of 1000 images of 1 soft toy from different angles. Example: dataset
I have to use some neural networks and train to detect my toy and also output its angle. I want to see: Class Probability Angle.
Example: wanted output
Is there a way to modify SSD or YOLO with Tensorflow or Darknet to modify framework/network to even calculate and output angle in YOLO for example?
While searching the internet I didn't find network example that will do something like that.

Which is best for object localization among R-CNN, fast R-CNN, faster R-CNN and YOLO

what is the difference between R-CNN, fast R-CNN, faster R-CNN and YOLO in terms of the following:
(1) Precision on same image set
(2) Given SAME IMAGE SIZE, the run time
(3) Support for android porting
Considering these three criteria which is the best object localization technique?
R-CNN is the daddy-algorithm for all the mentioned algos, it really provided the path for researchers to build more complex and better algorithm on top of it.
R-CNN, or Region-based Convolutional Neural Network
R-CNN consist of 3 simple steps:
Scan the input image for possible objects using an algorithm called Selective Search, generating ~2000 region proposals
Run a convolutional neural net (CNN) on top of each of these region proposals
Take the output of each CNN and feed it into a) an SVM to classify the region and b) a linear regressor to tighten the bounding box of the object, if such an object exists.
Fast R-CNN:
Fast R-CNN was immediately followed R-CNN. Fast R-CNN is faster and better by the virtue of following points:
Performing feature extraction over the image before proposing regions, thus only running one CNN over the entire image instead of 2000 CNN’s over 2000 overlapping regions
Replacing the SVM with a softmax layer, thus extending the neural network for predictions instead of creating a new model
Intuitively it makes a lot of sense to remove 2000 conv layers and instead take once Convolution and make boxes on top of that.
Faster R-CNN:
One of the drawbacks of Fast R-CNN was the slow selective search algorithm and Faster R-CNN introduced something called Region Proposal network(RPN).
Here’s is the working of the RPN:
At the last layer of an initial CNN, a 3x3 sliding window moves across the feature map and maps it to a lower dimension (e.g. 256-d)
For each sliding-window location, it generates multiple possible regions based on k fixed-ratio anchor boxes (default bounding boxes)
Each region proposal consists of:
an “objectness” score for that region and
4 coordinates representing the bounding box of the region
In other words, we look at each location in our last feature map and consider k different boxes centered around it: a tall box, a wide box, a large box, etc. For each of those boxes, we output whether or not we think it contains an object, and what the coordinates for that box are. This is what it looks like at one sliding window location:
The 2k scores represent the softmax probability of each of the k bounding boxes being on “object.” Notice that although the RPN outputs bounding box coordinates, it does not try to classify any potential objects: its sole job is still proposing object regions. If an anchor box has an “objectness” score above a certain threshold, that box’s coordinates get passed forward as a region proposal.
Once we have our region proposals, we feed them straight into what is essentially a Fast R-CNN. We add a pooling layer, some fully-connected layers, and finally a softmax classification layer and bounding box regressor. In a sense, Faster R-CNN = RPN + Fast R-CNN.
YOLO:
YOLO uses a single CNN network for both classification and localising the object using bounding boxes. This is the architecture of YOLO :
In the end you will have a tensor of shape 1470 i.e 7*7*30 and the structure of the CNN output will be:
The 1470 vector output is divided into three parts, giving the probability, confidence and box coordinates. Each of these three parts is also further divided into 49 small regions, corresponding to the predictions at the 49 cells that form the original image.
In postprocessing steps, we take this 1470 vector output from the network to generate the boxes that with a probability higher than a certain threshold.
I hope you get the understanding of these networks, to answer your question on how the performance of these network differs:
On the same dataset: 'You can be sure that the performance of these networks are in the order they are mentioned, with YOLO being the best and R-CNN being the worst'
Given SAME IMAGE SIZE, the run time: Faster R-CNN achieved much better speeds and a state-of-the-art accuracy. It is worth noting that although future models did a lot to increase detection speeds, few models managed to outperform Faster R-CNN by a significant margin. Faster R-CNN may not be the simplest or fastest method for object detection, but it is still one of the best performing. However researchers have used YOLO for video segmentation and by far its the best and fastest when it comes to video segmentation.
Support for android porting: As far as my knowledge goes, Tensorflow has some android APIs to port to android but I am not sure how these network will perform or even will you be able to port it or not. That again is subjected to hardware and data_size. Can you please provide the hardware and the size so that I will be able to answer it clearly.
The youtube video tagged by #A_Piro gives a nice explanation too.
P.S. I borrowed a lot of material from Joyce Xu Medium blog.
If your are interested in these algorithms you should take a look into this lesson which go through the algoritmhs you named : https://www.youtube.com/watch?v=GxZrEKZfW2o.
PS: There is also a Fast YOLO if I remember well haha !
I have been working with YOLO and FRCNN a lot. To me the YOLO has the best accuracy and speed but if you want to do research on image processing, I will suggest FRCNN as many previous works are done with it, and to do research you really want to be consistent.
For Object detection, I am trying SSD+ Mobilenet. It has a balance of accuracy and speed So it can also be ported to android devices easily with good fps.
It has less accuracy compared to faster rcnn but more speed than other algorithms.
It also has good support for android porting.