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Locating edges and removing ringing artifacts in JPEG images by frequency-domain analysis
Summary
This study introduces a novel method for detecting edges in JPEG images by analyzing Discrete Cosine Transform (DCT) coefficients in the frequency domain. This approach significantly reduces computational cost for edge detection and artifact reduction in compressed images.
Area of Science:
- Digital Image Processing
- Computer Vision
- Signal Processing
Background:
- JPEG compression introduces artifacts like ringing.
- Existing edge detection methods require full image decompression.
- Discrete Cosine Transform (DCT) is central to JPEG compression.
Purpose of the Study:
- To develop an efficient edge detection method for JPEG-compressed images.
- To leverage frequency-domain information (DCT coefficients) for edge localization.
- To apply the developed method for mitigating JPEG ringing artifacts.
Main Methods:
- Operates directly on quantized DCT coefficients in the frequency domain.
- Derives an equation for edge location from DCT coefficients of a block.
- Reduces computational complexity compared to pixel-domain methods.
Main Results:
- Successfully locates edges in JPEG-coded image blocks.
- Achieves significant operational savings by avoiding dequantization and pixel transformation.
- Demonstrates a technique for alleviating ringing artifacts using the proposed method.
Conclusions:
- Frequency-domain edge detection on DCT coefficients is computationally efficient.
- The method offers a viable approach for artifact reduction in compressed images.
- This technique enhances image processing workflows for compressed visual data.
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