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Convolutional Recurrent Neural Network For Text Recognition

Navdeep Singh Gill | 03 May 2023


Even with the rise of typewriters and computers today, handwritten documents are still common due to personal preferences and the technical challenges of fully migrating to digital text. Despite their authenticity, handwritten documents can develop various physical problems over time. Additionally, handwriting varies from person to person and, unlike digital text, is not always legible when read and understood by others. So here comes the CRNNs (Convolutional Recurrent Neural Networks), using which this challenge is solved.

According to a report by Markets, the OCR market is expected to grow from $7.9 billion in 2020 to $13.4 billion by 2025 at a compound annual growth rate (CAGR) of 11.0%. The market size and share are expected to be determined by factors such as the growing need for automation and digitization, advancements in artificial intelligence and machine learning, and efficient data capture and precision.

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What is Text Recognition?

Text recognition, also known as optical character recognition (OCR), converts printed or handwritten text into a digital format that is easy to edit, search and analyze. It involves analyzing images of text and recognizing the characters and words they contain.
The text recognition process usually involves several steps, such as pre-processing the image to remove noise and improve contrast, segmenting the image into individual characters or words, using algorithms for machine learning to recognize characters, then combining the recognized characters into words and sentences.
OCR (Optical Character Recognition) is a rapidly growing market due to the growing demand for document scanning and the need for efficient and accurate data capture. OCR has become an essential technology in many industries, including banking, healthcare, government, and education.

Some of the opportunities in the OCR market include:

  1. The Rise of Big Data Analytics: As digital data generated daily increases, OCR can scan and extract data from unstructured data sources such as images and documents.
  2. Machine Learning and Deep Learning Advances: OCR can be significantly improved using advanced machine learning algorithms and deep neural networks, resulting in accuracy and increased efficiency.

Text Recognition using Deep Learning

Deep learning has revolutionized the field of text recognition, resulting in dramatic improvements in accuracy and performance. There are several deep learning-based text recognition approaches, including.

  • Convolutional Neural Networks (CNNs): CNNs are often used for image-based text recognition. An input image is powered by convolutional layers that extract features and learn the text representation. The CNN output is then passed to a recurrent neural network (RNN) for further processing and text recognition.
  • Recurrent Neural Networks (RNNs): RNNs are widely used in sequence-based text recognition, such as handwriting and speech recognition. RNNs use feedback loops to process sequential data, allowing them to capture long-term dependencies and contextual information.
  • Encoder-decoder Networks: Encoder-decoder networks are used for end-to-end text recognition. An input image is first encoded into a feature vector and then decoded into a sequence of characters or words. These networks can be trained end-to-end, increasing efficiency and accuracy.
Deep Learning algorithms can give highly accurate and trustworthy results. Taken From Article, Deep Learning Challenges and Solutions

Comparison of Deep Convolutional Neural Networks (DCNN) and RNN

Deep convolutional neural networks (DCNN) and recurrent neural networks (RNN) are two popular types of neural networks used in deep learning. Both DCNNs (Deep Convolutional Neural Networks) and RNNs showed impressive performance in various tasks, including image and text recognition. However, they differ in their architecture and functionality.

Here are some critical differences between DCNNs and RNNs:

  1. Architecture: DCNNs are typically designed for image-based tasks and have a feedback architecture that includes convolution and clustering layers to extract features from the input image. In contrast, RNNs are designed for sequence-based tasks and have a recurrent architecture with a feedback loop for processing sequence data.
  2. Memory: RNNs have a memory component that allows them to retain information about previous inputs and sequential process data, unlike DCNNs. This makes RNNs better suited for tasks involving processing data sequences, such as speech recognition or language modeling.
  3. Input Size: DCNNs are designed to handle fixed-size input frames, while RNNs can handle variable-length input sequences. This makes RNNs more flexible and better suited for tasks involving variable-length sequences, such as natural language processing or speech recognition.
An artificial neural network with multiple input and output layers, mainly used for computer vision. Taken From Article, Convolutional Neural Network Use Cases

What are Convolutional Recurrent Neural Networks?

The full name of CRNN is Convolutional Recurrent Neural Network, which is a neural network architecture that combines the advantages of convolutional neural networks (CNN) and recurrent neural networks (RNN).

CRNNs (Convolutional Recurrent Neural Networks) are typically used to process and classify sequence data such as speech, text, and images. Their ability to handle variable-length sequential data and capture long-term dependencies makes them particularly effective in tasks that require understanding and modeling contextual and temporal information. CRNNs are powerful tools for modeling and processing sequential data, demonstrating peak performance on various tasks.

CRNNs work as follows:

  1. Input: The input to a CRNN is a sequence of data, such as images or audio samples.
  2. Convolutional Layers: The input sequence is fed by convolutional layers that extract features from the input. These layers are similar to those used in CNNs and are particularly effective for image-based inputs.
  3. Recurrent Layers: The output of a convolutional layer is then fed by one or more recurrent layers, which are particularly effective for processing sequential data. Repeating layers maintain a hidden state that captures information about previous entries in the sequence.
  4. Connections between convolutional and recurrent layers: The output of a convolutional layer is usually sampled before being fed into a recurrent layer. This reduces the network's computational complexity while preserving essential input characteristics.
  5. Output: The output of the last iterative layer goes through the fully connected final layer, which produces a prediction for the input sequence. This prediction can be a sequence of characters, words, or other outputs relevant to the task.

What are the challenges of Convolutional Recurrent Neural Networks?

Although convolutional recurrent neural networks (CRNNs) have many advantages, their use also presents some challenges. Here are some of the main challenges of CRNNs:

  • High Computational Complexity: CRNNs are computationally intensive, especially compared to simpler models like CNNs. This can make them challenging to train and deploy on low-power devices such as smartphones or embedded systems.
  • Challenging Architectural Design: CRNN requires careful design of convolutional and recurrent layers and how they are combined. Choosing exemplary architecture can be a long and difficult process.
  • Training Difficulty: Training CRNNs can be challenging, especially when working with large datasets. These models can suffer from problems such as overfitting, where the model learns too close to the training data and does not generalize well to new data.
  • Limited Interpretability: CRNNs can be challenging to interpret like other deep learning models. Understanding why a model makes specific predictions can be difficult and a problem in some applications.
A group of algorithms that certify the underlying relationship in a set of data similar to the human brain. Taken From Article, Artificial Neural Networks Applications

Use Cases of CRNN

The use cases of CRNNs are listed below:

Social Media

One possible use case for CRNNs in social media monitoring is sentiment analysis. Social media platforms generate vast amounts of textual data daily, and businesses and organizations can use sentiment analysis to understand what people think of their brand, product, or service. CRNNs can be trained on large datasets of social media posts to recognize patterns in the language used and determine whether a post has positive, negative, or neutral sentiment.

Another use case for CRNN in social media monitoring is topic modeling. Topic modeling is identifying themes or themes in large datasets of text documents.

Medical Drug Labels

CRNNs (Convolutional Recurrent Neural Networks) can be used for various tasks related to medication labels, such as:

  1. Text Recognition: CRNNs can be trained to recognize text on medication labels, which is helpful for automatic data extraction and analysis.
  2. Classification: CRNNs can be used to classify drug labels based on their content, such as whether they contain warnings, dosage information, or drug interactions.
  3. Information Retrieval: CRNNs can be used to retrieve specific information from drug labels, such as the side effects of a specific drug or the recommended dosage for a specific age group.

Collectively, CRNNs can help automate and simplify the process of analyzing and understanding medication labels, improving patient safety and healthcare outcomes.

What is the future scope of Convolutional Recurrent Neural Networks?

CRNNs (Convolutional Recurrent Neural Networks) show great potential in a wide range of applications, and there are several exciting future directions for research and development in this area:

  1. Multimodal Learning: One promising direction is to combine CRNNs with Other types of neural networks are combined. Networks include convolutional neural networks (CNN) for image processing and transformer networks for natural language processing. This approach allows for more complex multimodal learning and inference.
  2. Reinforcement Learning: Another promising direction is to use reinforcement learning to train CRNNs to make decisions and act based on input data, such as in robotics or autonomous systems.
  3. Interpretability and Interpretability: As deep learning models become more complex, techniques are growing needed to help explain and explain their decisions. Future research on CRNNs may focus on developing methods for interpretability and explainability.
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CRNN (Convolutional Recurrent Neural Network) is a powerful class of deep learning models that combines convolutional neural network (CNN) and recurrent neural network (RNN) to process sequential data. They have been used successfully in various applications, including speech recognition, image captioning, handwriting recognition, and natural language processing. CRNN is particularly suited to tasks involving sequential data and variable-length input, such as text and speech. They can learn to capture long-term dependencies in input data and make predictions based on context.