Key Concepts of Photogrammetry
Photogrammetry involves taking multiple overlapping photographs from different perspectives and using them to reconstruct a three-dimensional space. Here are some essential concepts:
Overlap: Essential for accurate 3D modeling, each photograph should overlap with the next by about 60-80%. This overlap enables the software to match points across images, crucial for stitching them into a cohesive model.
Resolution: The detail in your final model is highly dependent on the camera's resolution. Higher resolution images yield more detailed 3D models.
Quick Tutorial on Capturing Images for Drone Photogrammetry
Equipment Setup
Ensure your drone is equipped with a high-resolution camera. Check that all camera settings (like ISO, shutter speed, and aperture) are consistent to avoid variations in lighting and quality across images.
2. Planning the Capture
Choose the Right Conditions: Select a day with good weather—clear skies and low wind are ideal for stable and clear imagery.
Plan the Coverage: Determine the area you need to model and plan a flight path that ensures sufficient overlap between images. Many drone applications provide tools to automate this planning, ensuring optimal coverage.
3. Capturing Images
Start the Capture: Follow the planned route, ensuring each image overlaps significantly with the previous one. This can be manually controlled or set to automatic in many drone systems.
Monitor Consistency: Keep the flight altitude and speed consistent to ensure uniform image quality and overlap.
4. Image Processing
Software Processing: Once the images are captured, upload them to photogrammetry software of choice. The software will align the images based on their overlapping regions and stitch them into a point cloud and then a 3D model.
Adjust and Refine: Clean up your mesh in your 3D modeling software of choice.
Understanding the basic concepts of photogrammetry and following these steps for image capture can help you create detailed and accurate 3D models from drone photos. This technique is invaluable for us through a variety of use cases from mapping, surveying, landscape visualization and object digitization.