Recently, there has been a significant shift in the field of natural language processing (NLP), towards the use of transformers. Some examples of specific NLP tasks that Transformers have been used for include Language Translation, Text Generation, Text Summarization, Sentiment Analysis, Dialogue Generation and language modelling.
Transformers, which were first introduced in a 2017 paper by Google researchers. Unlike RNNs and CNNs, transformers are based on the attention mechanism, which allows the model to focus on specific parts of the input when making predictions. Essentially, the transformer model first encodes the input text into a fixed-size representation and then applies a series of self-attention mechanisms to “attend” to different parts of the encoded text when making predictions.
Advantages of Transformers over CNN models:
The key advantage of transformers is that they allow the model to handle long-term dependencies and sequential data much more effectively than RNNs and CNNs. This is because the attention mechanism allows the model to focus on specific parts of the input rather than processing the entire input in a sequential or grid-like manner. Additionally, the transformer model can be parallelized, which enables faster training and inference.
Advantages of transformer for medical image analysis and computer vision tasks:
- Image classification: Transformers can be used to classify images into different categories, such as identifying the presence of specific objects or diseases in an image.
- Object detection: Transformer-based models can be trained to identify and locate specific objects within an image, such as detecting tumors in medical images.
- Image segmentation: Transformers can be used to segment images into different regions, such as identifying the boundaries of different organs or tissues in medical images.
- Image captioning: Transformers can be used to generate captions that describe the content of an image, which can be useful for image retrieval and search tasks.
- Video analysis: Transformers can be applied to video data in a similar way to how they are applied to image data to perform tasks such as object tracking and video summarization.
- Medical Image Analysis: Transformers have been used in medical imaging to identify and locate specific objects or regions within an image, such as tumors, blood vessels, or organs. They can also be used to classify medical images according to certain criteria, such as malignancy or stage of the disease.
- Medical Diagnosis: Transformer-based models can be trained to diagnose diseases from medical images, such as identifying potential tumors in mammograms or detecting signs of retinal diseases in fundus images.
- Medical Image Generation: Transformers have been used to generate medical images such as CT, or MRI scans from other modalities, like ultrasound, in order to provide more detailed and accurate images.
Limitations of transformers:
- High computational cost.
- Have large number of parameters and require a lot of memory.
- Not suited to tasks that involve small objects, as they are not able to capture the fine-grained details of the image.
- Additionally, Transformers are not as well suited to tasks that require information about the spatial relationships between pixels or voxels in an image.
- They are not able to take advantage of the natural spatial hierarchies present in images. CNNs, by design, take advantage of the hierarchy of features at different scales, which allows them to learn increasingly complex features as they move deeper into the network.