Calculate the minimum camera resolution needed to detect defects of a specific size. Enter your inspection parameters below.
1. Defect & Inspection Parameters
mm (millimetres)
2. Field of View
mm
mm
3. Safety Factor
How This Calculator Works
The calculation uses the Nyquist sampling theorem: to reliably detect a feature, you need at least 2 pixels across it. For classification or measurement, more pixels are required. The formula used is:
Pixels Required = (FOV Width / Defect Size) × Pixels per Defect × Safety Factor
Resolution (MP) = Horizontal Pixels × Vertical Pixels / 1,000,000
Resolution (MP) = Horizontal Pixels × Vertical Pixels / 1,000,000
Understanding the Results
Pixels per Defect Guidelines
| Application | Pixels Needed | Why |
|---|---|---|
| Detection only | 2-3 pixels | Nyquist minimum - can tell “something is there” |
| Classification | 5-7 pixels | Enough detail to categorise defect type |
| Measurement | 10+ pixels | Sub-pixel accuracy for dimensions |
| Character reading | 3+ pixels per stroke | OCR requirements |
Common Camera Resolutions
| Resolution | Pixels | Typical Cost | Best For |
|---|---|---|---|
| 2MP (1080p) | 1920×1080 | £50-200 | Small FOV, large defects |
| 5MP | 2592×1944 | £150-400 | General inspection |
| 8MP (4K) | 3840×2160 | £300-700 | Medium precision |
| 12MP | 4096×3072 | £500-1200 | High precision |
| 20MP+ | 5472×3648+ | £1000+ | Micro-defect detection |
Next Steps
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