PPF (Pixels Per Foot) indicates the level of detail captured by a camera. It’s calculated using the formula:
PPF = Horizontal Pixels / Field of View Width
In this formula, the Field of View Width is the width (in feet) of the area captured by the camera at the target distance.
When the FoV width is measured directly at the target distance, you can calculate the PPF with a simple division. For example, a 1080p camera with 1920 horizontal pixels covering a 10‑foot wide area gives:
PPF = 1920 / 10 = 192
This means there are 192 pixels for every foot in the captured image.
For high-quality imaging—essential for tasks such as facial recognition and license plate reading—a PPF between 60 and 180 (or around 192 in our examples) is ideal. With higher resolution, you can increase the FoV width (or distance to target) while still maintaining the desired PPF.
The table below shows recommended examples for various camera resolutions. The recommended FoV width is calculated using the formula:
FoV Width = Horizontal Pixels / Target PPF
(with a target PPF ≈ 192 for high quality).
| Camera Resolution | Horizontal Pixels | Recommended FoV Width (ft) | Calculated PPF | Quality Category |
|---|---|---|---|---|
| 1080p | 1920 | 10.0 | 1920 ÷ 10 = 192 | High Quality |
| 3 MP | 2048 | 2048 ÷ 192 ≈ 10.7 | 2048 ÷ 10.7 ≈ 191.3 | High Quality |
| 5 MP | 2560 | 2560 ÷ 192 ≈ 13.3 | 2560 ÷ 13.3 ≈ 192.5 | High Quality |
| 8 MP | 3840 | 3840 ÷ 192 = 20.0 | 3840 ÷ 20 = 192 | High Quality |
| 12 MP | 4000 | 4000 ÷ 192 ≈ 20.8 | 4000 ÷ 20.8 ≈ 192.3 | High Quality |
| 16 MP | 5120 | 5120 ÷ 192 ≈ 26.7 | 5120 ÷ 26.7 ≈ 191.8 | High Quality |
These examples demonstrate that as the resolution increases, the camera can cover a wider area (or a further target distance) while still maintaining a high-quality PPF.
While resolution and FoV width are critical for calculating PPF, other factors can also affect the final image quality:
