Magnetic Anomaly Detection Based on Energy-Concentrated Discrete Cosine Wavelet Transform
Bibliographic record
Abstract
The magnetic anomaly signal tends to be contaminated by ambient environmental noise due to the complexity and diversity in the field of magnetic anomaly detection (MAD). The current denoising methods are effective in improving the signal-to-noise ratio (SNR). However, most of them are only applicable to the Gaussian noise and perform poorly for the practical geomagnetic noise, that is the nonstationary noise with a power spectral density (PSD) of 1/ <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f<sup>a</sup></i> . To solve this issue, a MAD method based on energy concentrated discrete cosine wavelet transform is proposed in this paper. A novel framework through fusing wavelet transform and discrete cosine transform, dubbed WT-DCT, is constructed, which consists of abnormal signal acquisition, frequency domain energy concentration, and discrete wavelet transformation. The SNR of the magnetic anomaly is improved by extracting the principal components of the scale signal in wavelet transformation through the discrete cosine transform. Through comparing the WT-DCT to four commonly used and accepted methods with extensive simulations and field tests, the results demonstrate that with variations of the geomagnetic noise strengths in the range from 250 nT to 1000 nT, the proposed WT-DCT achieves the highest SNR improvement by about 44.81% and the best structural similarity (SSIM) improvement by about 84.75%.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".