I've got a bunch of images (~3000) which have been manually classified (approved/rejected) based on some business criteria. I've processed these images with Google Cloud Platform obtaining annotations and SafeSearch results, for example (csv format):
file name; approved/rejected; adult; spoof; medical; violence; annotations
A.jpg;approved;VERY_UNLIKELY;VERY_UNLIKELY;VERY_UNLIKELY;UNLIKELY;boat|0.9,vehicle|0.8
B.jpg;rejected;VERY_UNLIKELY;VERY_UNLIKELY;VERY_UNLIKELY;UNLIKELY;text|0.9,font|0.8
I want to use machine learning to be able to predict if a new image should be approved or rejected (second column in the csv file).
Which algorithm should I use?
How should I format the data, especially the annotations column? Should I obtain first all the available annotation types and use them as a feature with the numerical value (0 if it doesn't apply)? Or would it be better to just process the annotation column as text?
I would suggest you try convolutional neural networks.
Maybe the fastest way to test your idea if it will work or not (problem could be the number of images you have, which is quite low), is to use transfer learning with Tensorflow. There are great tutorials made by Magnus Erik Hvass Pedersen, who published them on youtube.
I suggest you go through all the videos, but the important ones are #7 and #8.
Using transfer learning allows you to use the models they build at google to classify images. But with transfer learning, you are able to use your own data with your own labels.
Using this approach you will be able to see if this is suitable for your problem. Then you can dive into convolutional neural networks and create the pipeline that will work the best for your problem.
Related
I use VNImageRequestHandler and VNDetectRectanglesRequest to handle request to find rectangles in a image. But since Vision in iOS11 only provide barcode、rectangle、face finding，but I want to find cars in an image ,what should I change code to find specify object in an image?
If you’re looking for Apple to create an API named VNDetectCarRequest you should probably file a feature request. (And if it happens, I’m sure the “Apple is making a car!” rumor mill will start up again...)
For general-purpose image recognition, the path to take with Vision is to use VNCoreMLRequest and supply a machine learning model trained for the image recognition task you have in mind.
On the native programming side, all image recognition/classification tasks are the same — you can start by reusing Apple’s Classifying Images with Vision and Core ML sample code, which sets up VNCoreMLRequest and handles the VNClassificationObservation results it produces. The special sauce that changes a general “what is this” classifier into a “hotdog or not a hotdog” classifier or a “what kind of vehicle is this (if it’s one at all)” classifier is all in the model.
There might be a machine learning model that already does the task you’re looking for out there — if you find one, you can wrap it in a Core ML Model file using the scripts Apple provides.
Otherwise, you’ll need to look at one of the general purpose image classifier models out there (again, there are several already conveniently gathered on developer.apple.com) and work on specializing / retraining it to your more specific task. That part of your work is outside Apple’s API ecosystem, and there are many possible options. Web searches for “train caffe image model” or “train keras image model” or similar should be helpful there.
Once you’ve trained your model, use the Core ML tools to get it into Core ML to use with Vision.
I'm new to machine learning and trying to figure out where to start and how to apply it to my app.
My app is pulling a bunch of health metrics and based on all of them is suggesting a dose of medication (some abstract medication, doesn't matter) to take. Taking a medication is affecting health metrics and I can see if my suggestion was right of if it needs adjustments to be more precise the next time. Medications are being taken constantly so I have a lot of results and data to work with.
Does that seem like a good case for machine learning and using some of neural networks to train and make better predictions? If so - could you recommend an example for Tensorflow or Keras?
So far I only found image recognition examples and not sure how to apply similar algorithms to my problem.
I'm also a beginner into machine learning, but based on my knowledge, one way would be to use supervised learning with Keras, which uses Tensorflow as a backend. Keras is a lot easier to program than Tensorflow, but eventually Tensorflow might as well do the trick (depending on your familiarity with machine learning libraries).
You mentioned that your algorithm suggests medication based on data (from the patient).
One way to predict medication is to store all your preexisting data in a CSV file, and use the CSV module to read it. This tutorial covers the basics of reading CSV files (https://pythonprogramming.net/reading-csv-files-python-3/).
Next, you can store the data in a multi-dimensional array, and run a neural network through it. Just make sure that you have sufficiently enough data (the more the better) in comparison with the size of your neural network.
Another way, as you mentioned, would be using Convolutional Neural Networks, which theoretically could and should work, but I have very little experience programming them, so I'm afraid I can't give you any advice for that (you can program CNNs in both Keras and Tensorflow).
I do wish you good luck in your project!
Can anyone advise me way to build effective face classifier that may be able to classify many different faces (~1000)?
And i have only 1-5 examples of each face
I know about opencv face classifier, but it works bad for my task (many classes, a few samples).
It works alright for one face classification with small number of samples. But i think that 1k separate classifier is not good idea
I read a few articles about face recognition but methods from these articles reqiues a lot of samples of each class for work
PS Sorry for my writing mistakes. English in not my native language.
Actually, for giving you a proper answer, I'd be happy to know some details of your task and your data. Face Recognition is a non-trivial problem and there is no general solution for all sorts of image acquisition.
First of all, you should define how many sources of variation (posing, emotions, illumination, occlusions or time-lapse) you have in your sample and testing sets. Then you should choose an appropriate algorithm and, very importantly, preprocessing steps according to the types.
If you don't have any significant variations, then it is a good idea to consider for a small training set one of the Discrete Orthogonal Moments as a feature extraction method. They have a very strong ability to extract features without redundancy. Some of them (Hahn, Racah moments) can also work in two modes - local and global feature extraction. The topic is relatively new, and there are still few articles about it. Although, they are thought to become a very powerful tool in Image Recognition. They can be computed in near real-time by using recurrence relationships. For more information, have a look here and here.
If the pose of the individuals significantly varies, you may try to perform firstly pose correction by Active Appearance Model.
If there are lots of occlusions (glasses, hats) then using one of the local feature extractors may help.
If there is a significant time lapse between train and probe images, the local features of the faces could change over the age, then it's a good option to try one of the algorithms which use graphs for face representation so as to keep the face topology.
I believe that non of the above are implemented in OpenCV, but for some of them you can find MATLAB implementation.
I'm not native speaker as well, so sorry for the grammar
Coming to your problem , it is very unique in its way. As you said there are only few images per class , the model which we train should either have an awesome architecture which can create better features within an image itself , or there should be an different approach which can achieve this task .
I have four things which I can share as of now :
Do data pre-processing and then create a bigger dataset and train on a neural network ideally. Here, we can do pre-processing like:
- image rotation
- image shearing
- image scaling
- image blurring
- image stretching
- image translation
and create atleast 200 images per class. Please checkout opencv documentation which provides many more methods on how you can increase the size of your dataset. Once you do this, then we can apply transfer learning , which is a better approach than training a neural network from scratch.
Transfer learning is a method where we train a network on our own custom classes , and this network is already pre-trained on 1000's of classes. Since our data here is very less, I would prefer transfer learning only. I have written a blog on how you can approach this using tranfer learning after you have the required amount of data. It is linked here. Face recognition also is a classification task itself, where each human is a separate class. So, follow the instructions given in the blog , may be it would help you create your own powerful classifer.
Another suggestion would be , after creating a dataset , encode them properly. This encoding would help you preserve the features in an image and can help you train better networks. VLAD ,Fisher , Bag of Words are few encoding techniques. You can search few repositories online which have implemented these already on ORL database. Once you encode , train the network on the encodings , you will obviously see a better performance.
Even do check out , Siamese network here which is meant for this purpose I feel . Here they compare two images with similar characteristics on different networks and there by achieve better classification accuracies . Git repository is here.
Another standard approach would be using SVM , Random forests since the data is less. If you still prefer neural networks the above methods would serve you the purpose. If you intend to go with encodings , then I would suggest random forests , as it is highly preferrable in learning and flexible too.
Hopefully , this answer would help you proceed in the right direction of achieving things.
You might want to take a look at OpenFace, a Python and Torch implementantion of face recognition with deep neural networks: https://cmusatyalab.github.io/openface/
How to perform image classification from mahout? How to convert the image to a form which is accepted by mahout classification algorithms? Is the any starter code to start with? Please share me some starter tutorials. Is mahout good library for image classification?
There are two answers to your question:
The simple answer is that from a Mahout point of view classifying images is no different than classifying any other type of data. You find a suitable set of features to describe your data, and then: train, validate, test, and deploy.
The second answer is a bit more involved, and I'm going to summarize. In the case of images the step in which you compute a suitable set of features spans a whole research area (called computer vision). There are many methods: DHOG, direction of gradient, SURF, SIFT, etc. Depending on the images and what your expectations are, you may obtain reasonable results just using an existing method, or maybe not. It would be impossible to say without looking at your images and you telling us your objectives.
I'm trying to find a fast way to match descriptors from a database. My program works the following way:
1) Populates a database with descriptors of images (using proper feature detection algorithms)
2) Load an image
3) Extracts descriptor for that image and compares it to all descriptors in the DB, so it can find a proper match.
As you can imagine, it's very heavy to compute a comparison of 32 descriptors millions of times. I've used a hashing function, but that only works for two descriptors that are exactly the same, thus only matching two exactly identical images.
What do you suggest I use to speed up this search?
Cheers
EDIT:
I've decided to start by approaching a Neural Network solution. Here's a pretty good link for anyone who wants to get started on the subject.
What you are trying to accomplish is essentially called machine learning/classification. Directly comparing is really hopeless given the size of your database.
Just in case you are not aware of the terminology. The database that you have is called the learning-dataset. You need to use a machine learning algorithm like SVM (support vector machine), K-NN (K-nearest neighbours), Neural networks etc to learn a model. This model is later on used to predict the outcomes of an new and fresh instance, ie. the vector you want to compare your database with.
I would strong suggest the use of SVM, since it is the state of the art classifier in machine learning literature. There is an implementation of it called "SVM light".
http://svmlight.joachims.org/. It is also possible to do ranking with SVM-light. please have a look at that as well.
You can also try and use neural networks. I use neural network toolbox in matlab for this (nprtools) which is pretty neat.