I am using the Object Detection API and already have a trained model for my specific object classes.
With my task, there will be more and more object classes over time. Since retraining on the combined data sets takes very long, I am interested in a way to only train the pre-trained net on the new data.
I have found this:
Retrain Tensorflow Object detection API but since I would need to load the checkpoint on the already trained data and train it again on a combined dataset, which contains the old data, wouldn't that lead to severe over fitting on the old data?
No actually, we usually call this trick as fine-tune. The new training dataset containing both old classes and new classes enables CNN to learn a more general representation for all those classes.
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here I want to train a object detection model, so I have annotated the data using roboflow and then exported it as tfrecords and also got the (.pbtxt file) and after that I don't have any clue on how to train a can model from scratch with just 2,3 number of hidden layers. am not getting on how to use that tfrecord to fit in my model which I have created. please help me out.
tfrecord files are usually used with Tensorflow Object Detection. It's pretty old and I haven't seen it used in practice recently, but there's a Tensorflow Object Detection tutorial here that uses these tfrecord files.
If there's not a particular reason you need to use TF Object Detection I'd recommend using a newer and more well-supported model like YOLOv5 or YOLOv7.
I am using TF-Agents for a custom reinforcement learning problem, where I train a DQN (constructed using DqnAgents from the TF-Agents framework) on some features from my custom environment, and separately use a keras convolutional model to extract these features from images. Now I want to combine these two models into a single model and use transfer learning, where I want to initialize the weights of the first part of the network (images-to-features) as well as the second part which would have been the DQN layers in the previous case.
I am trying to build this combined model using keras.layers and compiling it with the Tf-Agents tf.networks.sequential class to bring it to the necessary form required when passing it to the DqnAgent() class. (Let's call this statement (a)).
I am able to initialize the image feature extractor network's layers with the weights since I saved it as a .h5 file and am able to obtain numpy arrays of the same. So I am able to do the transfer learning for this part.
The problem is with the DQN layers, where I saved the policy from the previous example using the prescribed Tensorflow Saved Model Format (pb) which gives me a folder containing model attributes. However, I am unable to view/extract the weights of my DQN in this way, and the recommended tf.saved_model.load('policy_directory') is not really transparent with respect to what data I can see regarding the policy. If I have to follow the transfer learning as I do in statement (a), I need to extract the weights of my DQN and assign them to the new network. The documentation seems to be quite sparse for this case where transfer learning needs to be applied.
Can anyone help me in this, by explaining how I can extract weights from the Saved Model method (from the pb file)? Or is there a better way to go about this problem?
I am trying to understand what I need from any pre-trained model used in the API regardless of any additional code found on the Tensorflow object detection API.
For example: ssd_mobilenet_v1_coco_2017_11_17, depending on what I have understood: it is a model that is already trained to detect objects (there is a classification to know the category of the object + Regression to bound the objects with rectangles and those rectangles are actually the x,y,w,h coordinates on the object).
How do we benefit from the regression output of that model (x,y,w,h coordinates) to use them in another model?
Let's assume we want to print out just the coordinates x,y,w,h of a detected object on an image without any need of the code of Tensorflow object detection API, how can we do that?
Certainly you can use the pretrained model provided in tensorflow object detection model zoo without installing object detection api. The alternative solution is to use opencv.
Opencv has provided both c++ and python api to call .pb models generated by tensorflow. Here is a nice tutorial.
I have trained the object detection API using ssd_mobilenet_v1_coco_2017_11_17 model to detect a custom object. But after training, the API only detects the custom object and not the objects for which the API is already trained. ssd_mobilenet_v1_coco_2017_11_17 model detect 90 objects.
Is there any way to add more classes to an existing model so that it can detect new objects along with the one it has been trained for?
This question is already asked here and some answer could be found here.
The very last layer of the networks is softmax layer. when the network is trained, the weights of the network is optimized for the exact number of classes on the training set. So, if you need to add a new class and also the classes it was trained, the easiest way is to get the original dataset it was trained on along with your new class images. Then start the training from the pre-trained model weights. The training should converge faster as it has to do relatively little adjustments.
I'm using tensorflow objection detection API with the coco dataset provided in the tutorial.
If I use the api to detect custom objects, how do I "add" to the list of objects being detected from the coco dataset? Is there a way to merge?
If you mean using a model which is trained on the COCO dataset to detect objects that are not in the COCO dataset, you cannot do that. I think you will need to train a model, in this case one already trained on COCO, on your new objects that you want to detect. There is a tutorial here that shows how to train a model on a custom dataset.
If you do not want to train a model you need to find one that is already trained for the objects that you want to detect.
Have I understood correctly?