After stacking, noise reduction is the next step to enhance your astrophotos. Here are common mathematical filters used:
- Median Filtering: Replaces each pixel with the median of neighboring pixels to remove outliers like cosmic rays.
- Gaussian Smoothing: Applies a weighted average that smooths noise but keeps edges sharp.
- Wavelet Transforms: Breaks the image into frequency layers, allowing selective noise removal at different scales.
Each method balances noise suppression with detail retention, making your final image cleaner without losing faint stars or nebula structures.
