I am working on a project that aims to detect objects in certain difficult circumstances. I ran a test with Mask_RCNN on a dataset that contains that specific type of difficult examples and it did a pretty good job in some of them.
But some other examples didn't get detected surprisingly, when there is no obvious reason. To understand the reason behind this performance difference, I've been adviced to use Tensorboard. But then I realized that its mostly used for training phase, as I understood from this video.
At the end of the video, however, they mention about an integration project of Tensorboard, namely the Tensorflow Debugger Integration. But unfortunately I could not find further information regarding the continuation about that feature.
Is there any way to visualize weights and activation maps inside a CNN during inference/evaluation phase?
The main difference between training and inference time for tensorboard will be the global_step value. Most graphs display global step as the x-axis. You can supply your own global step counter if you like, but you'll have to decide what the x-axis should represent to you in this case since "time" isn't really a logical construct during inference. Other tabs such as the images tab don't have a time component, so using them should be the same as during training.
The tensorflow debugger is a nice terminal debugger, but wouldn't really be related to what you're trying to do here. It's certainly not a visualization tool.
Another approach might be to simply generate your own plots and output a set of PDFs with the various visualizations you need using standard tools like matplotlib for each test image. I've found tools like XnView make it really easy to look through a lot of PDF visualizations to understand what's going on. I've used this approach quite effectively. If you want to view many hundreds or thousands of results quickly you might have an easier time if all the visuals are just dumped out to a directory.
Related
I am using the TF Object Detection API. I have a custom data set. I am training using SLURM jobs and calling the API scripts from within there. I am looking to try and tune hyperparameters found in the pipeline.config files. Unfortunately, in the documentation, this kind of process is not outlined. It seems like the process is to either use the sample configs or tune the hyperparameters by hand.
Tuning by hand is somewhat feasible, for example adjusting for two parameters for three values (batch size and steps) results in nine different .configs, but adding another hyperparameter to that boosts it up to twenty-seven files I need to keep track of. This does not seem like a good way to do it, particularly because it limits the values I can try and is clumsy.
It seems like there are libraries out there that hook into Keras and other more high-level frameworks, but I have found nothing that looks like it can take the results of the Object Detection API and actually optimize it.
Is it possible to do this with a pre-built library I don't know about? I would like to avoid having to edit the API implementation or coding this myself to minimize errors.
In TF 2.x, there are a whole set of image augmentation API, take tf.image.stateless_random_flip_up_down for example. Most of these will perform the said operation at random. What I like to find out is if there’s a way to interrogate what exactly has been perform for a specific image in a specific batch. This info is critical if the target prediction involve localization like points, bounding boxes, etc. Since affine transform (like translate) performed on image, the same operation should be used to “augment” the targets (y) in a consistent manner.
I think all the image transform API in TF2.X do not return this piece of info. I would like to see if there’s easier way than creating custom ones of my own. I have done this for the older Keras data augmentation API in the past by subclasses, and would prefer not to repeat the tedium if possible.
I guess your main goal is to write a data augmentation pipeline that changes both image and its labels.
Well, then I would recommend you to use Albumentaitons library instead. It is a very popular open-source library that can easily be integrated with Tensorflow and PyTorch frameworks.
Here is its documentation: https://albumentations.ai/
Let me know if it helps!
I successfully trained multi-classificator model, that was really easy with simple class related folder structure and keras.preprocessing.image.ImageDataGenerator with flow_from_directory (no one-hot encoding by hand btw!) after i just compile fit and evaluate - extremely well done pipeline by Keras!
BUT! when i decided to make my own (not cats, not dogs, not you_named) object detector - this is became a nightmare...
TFRecord and tf.Example are just madness! but ok, i almost get it (my dataset is small, i have plenty of ram, but who cares, write f. boilerplate, so much meh...)
The main thing - i just can't find any docs/tutorial how to make it with plain simple tf/keras, everyone just want to build up it on top of someone model, YOLO SSD FRCNN, even if they trying to detect completely new objects!!!
There two links about OD in official docs, and they both using some models underneath.
So my main question WHY ??? or i just blind..? -__-
It becomes a nightmare because Object Detection is way way harder than classification. The most simple object detector is this: first train a classifier on all your objects. Then when you want to detect objects in your image, slide a window over your image, and classify each window. Then, if your classifier is certain that a certain window is one of the objects, mark it as a successful detection.
But this approach has a lot of problems, mainly it's way (like waaaay) too slow. So, researcher improved it and invented RCNNs. That had it problems, so they invented Faster-RCNN, YOLO and SSD, all to make it faster and more accurate.
You won't find any tutorials online on how to implement the sliding window technique because it's not useful anyway, and you won't find any tutorials on how to implement the more advanced stuff because, well, the networks get complicated pretty quick.
Also note that using YOLO doesn't mean you should use the same weights as in YOLO. You can always train YOLO from scratch on your own data if you want by randomly initiliazing all the weights in the network layers. So the even if they trying to detect completely new objects!!! you mentioned isn't really valid. Also also note that I still would advise you to do use the weights they used in Yolo network. Transfer Learning is generally looked at as being a good idea, especially when starting out and especially in the image processing world, as many images share common features (like edges, for example).
I am having pretty much the same problem as my images are B/W diagrams, quite different from regular pictures, I want to train a custom model on just only diagrams.
I have found this documentation section in Tensorflow models repo:
https://github.com/tensorflow/models/blob/master/research/object_detection/README.md
It has a couple of sections explaining how to bring your own model and dataset in "extras" that could be a starting point.
I haven't tried Tensorflow yet but still curious, how does it store, and in what form, data type, file type, the acquired learning of a machine learning code for later use?
For example, Tensorflow was used to sort cucumbers in Japan. The computer used took a long time to learn from the example images given about what good cucumbers look like. In what form the learning was saved for future use?
Because I think it would be inefficient if the program should have to re-learn the images again everytime it needs to sort cucumbers.
Ultimately, a high level way to think about a machine learning model is three components - the code for the model, the data for that model, and metadata needed to make this model run.
In Tensorflow, the code for this model is written in Python, and is saved in what is known as a GraphDef. This uses a serialization format created at Google called Protobuf. Common serialization formats include Python's native Pickle for other libraries.
The main reason you write this code is to "learn" from some training data - which is ultimately a large set of matrices, full of numbers. These are the "weights" of the model - and this too is stored using ProtoBuf, although other formats like HDF5 exist.
Tensorflow also stores Metadata associated with this model - for instance, what should the input look like (eg: an image? some text?), and the output (eg: a class of image aka - cucumber1, or 2? with scores, or without?). This too is stored in Protobuf.
During prediction time, your code loads up the graph, the weights and the meta - and takes some input data to give out an output. More information here.
Are you talking about the symbolic math library, or the idea of tensor flow in general? Please be more specific here.
Here are some resources that discuss the library and tensor flow
These are some tutorials
And here is some background on the field
And this is the github page
If you want a more specific answer, please give more details as to what sort of work you are interested in.
Edit: So I'm presuming your question is more related to the general field of tensor flow than any particular application. Your question still is too vague for this website, but I'll try to point you toward a few resources you might find interesting.
The tensorflow used in image recognition often uses an ANN (Artificial Neural Network) as the object on which to act. What this means is that the tensorflow library helps in the number crunching for the neural network, which I'm sure you can read all about with a quick google search.
The point is that tensorflow isn't a form of machine learning itself, it more serves as a useful number crunching library, similar to something like numpy in python, in large scale deep learning simulations. You should read more here.
I'm very new to this stuff so please bear with me. I followed a quick simple video about image recognition/classification in YT and the program indeed could classify the image with a high percentage. But then I do have some other images that was incorrectly classified.
On tensorflow site: https://www.tensorflow.org/tutorials/image_retraining#distortions
However, one should generally avoid point-fixing individual errors in
the test set, since they are likely to merely reflect more general
problems in the (much larger) training set.
so here are my questions:
What would be the best way to correct the program's guess? eg. image is B but the app returned with the results "A - 70%, B - 30%"
If the answer to one would be to retrain again, how do I go about retraining the program again without deleting the previous bottlenecks files created? ie. I want the program to keep learning while retaining previous data I already trained it to recognize.
Unfortunately there is often no easy fix, because the model you are training is highly complex and very hard for a human to interpret.
However, there are techniques you can use to try and reduce your test error. First make sure your model isn't overfitting or underfitting by observing the difference between train and test errors. If either is the case then try applying standard techniques, such as choosing a deeper model and/or using more filters if underfitting or adding regularization if overfitting.
Since you say you are already classifying correctly a high percentage of the time, I would start inspecting misclassified examples directly to try and gain insight into what you might be able to improve.
If possible, try and observe what your misclassified images have in common. If you are lucky they will all fall into one or a small number of categories. Here are some examples of what you might see and possible solutions:
Problem: Dogs facing left are misclassified as cats
Solution: Try augmenting your training set with rotations
Problem: Darker images are being misclassified
Solution: Make sure you are normalizing your images properly
It is also possible that you have reached the limits of your current approach. If you still need to do better consider trying a different approach like using a pretrained network for image recognition, such as VGG.