How a Camera Sensor Works
A camera sensor is like a grid of tiny buckets (pixels) that collect photons (light particles). When light hits a pixel, it generates an electrical charge proportional to brightness. The longer the exposure, the more light collected â like leaving a bucket in the rain.
Shutter Types: Global vs Rolling
The shutter determines how the sensor captures the image. This is critical for drones because they're always moving.
Global Shutter: Exposes all pixels simultaneously â like blinking your eyes. Every pixel captures the same moment. No distortion during fast motion.
Rolling Shutter: Exposes pixels row by row, from top to bottom. During fast motion, the image appears skewed or warped â known as the "jello effect."
Lens Selection for Drones
The lens determines what the camera "sees." Key parameters:
| Parameter | Description | Drone Impact |
|---|---|---|
| Focal length | Determines magnification | Longer = zoom, narrower FOV |
| Aperture (f-stop) | Light gathering ability | Lower f = more light, shallower DOF |
| FOV | Coverage area | Wide = more context, less detail |
| Distortion | Barrel/pincushion effects | Needs correction for mapping |
Camera Settings for Drone Operations
| Application | Shutter Speed | ISO | Aperture | White Balance |
|---|---|---|---|---|
| Survey mapping | 1/1000+ | 100-400 | f/5.6-f/8 | Auto |
| Cinematic video | 1/60 (24fps) | 100-200 | Wide open | Manual |
| Thermal imaging | Auto | N/A | Fixed | N/A |
| Night flying | 1/30 or slower | 800-3200 | Wide open | Auto |
RAW vs JPEG for Drone Work
JPEG: Compressed, smaller files, processed in-camera. Good for quick sharing.
RAW: Uncompressed sensor data, much larger files. Allows post-processing flexibility â critical for professional survey and inspection work.
Hands-On Project: Camera Calibration Checker
Build a tool to check camera calibration quality using OpenCV:
Key Takeaways
- Camera sensors convert light to digital signals through Bayer filtering and ADC
- Global shutter prevents distortion; rolling shutter causes jello effect
- Lens selection determines FOV, magnification, and light gathering
- RAW format preserves more data for post-processing
- Camera calibration is essential for accurate measurements from drone imagery