Regardless of whether capturing with your mobile phone or some other camera, there are a few basic rules for capturing for Mapillary. Further below in this article, you'll find some extra guidelines as well as tips specific to capturing on foot, by bicycle, or by car, and a few different strategies for how to move as you capture different objects.
5 basic rules for capturing
- The main point when capturing is to keep on moving and to try and hold the camera itself still.
- Mapillary supports images in landscape orientation. Adjust the camera to be level with the horizon (the Mapillary apps have tilt lines on the camera screen to help with that).
- Normally you aim the camera towards the direction of movement, where the road in front of you meets the horizon.
- The ideal environment for a Mapillary sequence is to have the sun behind you, minimal traffic and fewer people about.
- Take many images in one sequence (at least 10, but more is better) and in close proximity to each other (5 m is good).
We use a computer vision technology called Structure from Motion (SfM) to create an immersive experience when you're viewing the sequences. SfM works based on overlapping points between different images. If you follow the above tips, your images will have enough overlap and you will end up with seeing something like this.
- Avoid capturing in the rain and in low-light situations. The images will turn out much worse than what you see with the human eye. (This particularly applies when you're in a car.)
- Keep a consistent angle of the camera. Most times you would keep it pointing straight ahead, although sometimes you may want to capture e.g. at a 90- or 45-degree angle with respect to your direction of moving. If you change the camera angle mid-capture, the sequences will end up looking jumpy and "dizzy".
- If you keep or mount the camera steady, you can lock the compass angle to the direction your device is pointing, instead of using the device's compass that might be affected by disturbances. There's a little arrow or compass icon at the top right of the app's Capture screen for changing that this setting.
- Turn off WiFi and Bluetooth to save battery while you capture. You might want to use a power bank (or a phone charger, if in a car) for extra power supply.
- For longer capture sessions, consider extra micro-SD cards to expand the memory available for capture (if your device supports it).
- Try to keep the camera in line with the horizon. It's a bit harder when walking compared to other modes of moving, but the tilt lines on the camera screen will help you.
- You can try putting the phone in a pouch around your neck or taped on your chest. That should help keep the camera steady.
- You might also try to use a selfie stick which might be more comfortable to hold than the phone itself.
- Normally you would use an automatic capture mode. However, you can also use the manual mode if you for some reason want custom control over when an image is captured.
- For example, the manual mode might be a good idea if your images turn out blurry—try stopping for each image you take.
- Ride slow and preferably on smooth surfaces. This has two reasons: to reduce blur that results from shocks absorbed by the bike and to make sure your phone doesn’t pop out of the holder.
- To be on the safe side, we strongly suggest that you use rubber bands or lanyards to secure your phone to the mount.
- For capturing on more bumpy rides (and also those on sand, gravel, and dirt roads) we recommend using an action camera.
- The position of the mount also affects potential glare from the dashboard (that will be visible in your images). You can also try a few other tricks for reducing glare:
- Remove any lighter objects from your dashboard.
- Cover the dashboard with a black matt cloth (like felt).
- Try a DIY polarizer filter. You can use a lens from disposable 3D glasses from the cinema—cut it out and tape it over your camera lens. You might want to try rotating and turning it around to find the position that works best for you.
- You can achieve really good results in terms of both quantity and quality of images by using an action camera or a rig of several cameras that you mount externally to the car.
Strategies for capturing different objects
Streets and roads
When you want to cover a street, make sure the camera is pointed in the direction of the street. If you have time, first cover one direction and then the other. When that is done, you can orientate the camera left or right to the direction of travel.
When walking around corners, it is best to take more images with lots of overlap to create smoother transitions. Selecting manual mode or adjusting the frequency of automatic capture can help achieve this.
For facades, point the camera to the left or right of the direction of travel. This works best on wide streets so that large parts of the facades are visible, and you are moving slowly. For the best viewing results, aim to have a 50% overlap between the images.
For panoramas, e.g. street intersections or spectacular views, you can use the automatic mode. The distance-based auto mode (default in the app) reacts to compass angle change, so you just need to turn around slowly and take images with enough overlap, which provides a nice viewing experience.
To capture a single focal point such as a statue or a small structure, orbit around it taking pictures at different angles. (In some cases, manual capture mode might be more suitable for this than automatic.)