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.
5 basic rules for capturing
- The main point when capturing is to keep on moving and to try to hold the camera still, pointing in one direction.
- 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. (Press play on the embedded sequence!)
- 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).
- Keep in mind that if you capture images that are several hundreds of meters apart from each other, they will be split into separate sequences after upload on our system. This may make it inconvenient for you to get an overview of your imagery later (both in the list on your profile and visualized on the map, where they'll only be represented by single dots).
- 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.
Note. Mobile phones are not the best choice when you want to capture while cycling. One reason is that your phone may quite easily pop out of the mount and get damaged. The other reason is that phones are usually not good at handling motion blur. We recommend that you use an action camera instead.
If you still decide to use your phone when cycling, here's what you should keep in mind.
- 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.
- 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.
Please sign in to leave a comment.