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Computer Vision Systems • Image Preprocessing (Augmentation, Normalization)Hard⏱️ ~3 min

Domain Specific Preprocessing Constraints

Medical Imaging Constraints
Medical images have strict preprocessing requirements. DICOM format contains metadata critical for interpretation. Window/level settings control how pixel values map to display. Wrong preprocessing leads to missed diagnoses.
Key constraints: Preserve original pixel values for regulatory compliance. Document all transformations applied. Avoid lossy augmentations that could mask pathology. Maintain aspect ratios that clinicians expect.
Satellite and Aerial Imagery
Satellite images have 12-16 bits per channel versus 8 bits for consumer photos. Spectral bands beyond visible RGB provide crucial information. Standard preprocessing designed for 8-bit RGB destroys this data.
Key constraints: Preserve full bit depth during preprocessing. Handle multiple spectral bands (not just RGB). Account for varying sun angles and atmospheric conditions across images. Geospatial metadata must survive preprocessing.
Document and Text Images
Text recognition requires different preprocessing than object classification. Orientation matters - upside-down text must be detected and corrected before OCR. Horizontal flipping is forbidden because it creates invalid characters.
Key constraints: Deskewing aligns rotated documents. Binarization separates text from background. Noise removal helps but aggressive filtering destroys thin strokes. Preserve aspect ratio - stretching distorts character shapes.
Choosing Domain-Appropriate Preprocessing
Start with domain expert consultation. Ask what transformations are acceptable for the specific use case. Test preprocessing on edge cases before training. Monitor for cases where preprocessing destroys critical information.
Key Insight: Generic preprocessing pipelines optimized for consumer photos often destroy critical information in specialized domains. Always validate with domain experts.

💡 Key Takeaways

✓Medical imaging requires preserved pixel values, documented transformations, and regulatory compliance

✓Satellite imagery uses 12-16 bit depth and multiple spectral bands - 8-bit RGB preprocessing destroys this data

✓Document/text images forbid horizontal flipping and require orientation detection, deskewing, and careful binarization

✓Generic preprocessing pipelines optimized for consumer photos often destroy critical domain-specific information

📌 Interview Tips

1Interview Tip: Ask about the domain before proposing preprocessing - satellite vs medical vs documents have opposite requirements

2Interview Tip: Mention regulatory constraints for medical imaging - transformations must be documented and reversible

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