This document explains multiple approaches to text summarization, combining frequency-based methods, position-based methods, TF-IDF-based scoring, and transformer-based models (HuggingFace Transformers).
The goal of summarization is to condense a longer body of text into its most important parts while retaining meaning.
Before applying summarization techniques, the text needs to be cleaned:
- Remove special characters and digits.
- Tokenize text into words and sentences.
- Lemmatize words using WordNetLemmatizer.
- Remove stopwords to reduce noise.
The cleaned text is then used in different summarization algorithms.
- Tokenize text into sentences.
- Count word frequency after removing stopwords.
- Normalize frequency values by dividing by the maximum frequency.
- Score each sentence based on word frequencies.
- Select the top-N sentences as the summary.
- Tokenize text into sentences.
- Score sentences based on their position in the text (earlier sentences often carry more importance).
- Select the top-N sentences by position score.
- Create a frequency matrix of words in each sentence.
- Compute Term Frequency (TF) and Inverse Document Frequency (IDF).
- Calculate TF-IDF scores for words.
- Score sentences by averaging TF-IDF values of words.
- Select the best sentences above a set threshold.
This method ensures that rare but important words have higher weight in the summary.
Input: Peter and Elizabeth took a taxi to attend the night party in the city. While in the party, Elizabeth collapsed and WAS rushed to the hospital.
Position-based summary:
Peter Elizabeth took taxi attend night party city party Elizabeth collapsed rushed hospital
- Uses pre-trained deep learning models such as
sshleifer/distilbart-cnn-12-6
. - Capable of generating abstractive summaries, unlike extractive methods.
- Requires the transformers library and a summarization pipeline.
- Frequency-based summarization selects sentences with the most frequent important words.
- Position-based summarization prioritizes sentences based on placement in the document.
- TF-IDF summarization balances word frequency with uniqueness, highlighting rare but meaningful terms.
- Transformer-based summarization (e.g., DistilBART) provides abstractive summaries, rephrasing content instead of just extracting sentences.
Each approach has strengths and trade-offs:
- Rule-based methods (frequency, TF-IDF, position) are fast and simple.
- Transformer-based methods are more accurate but computationally expensive.