The past few weeks’ releases have introduced several improvements to Misty’s simultaneous localization & mapping (SLAM) system. While still alpha features (and likely to be unreliable at this time), we’re eager to get feedback from the community, and we’ve prepared a set of tips to help you get the most out of Misty’s mapping & tracking capabilities in their current state. A step-by-step guide to mapping and tracking with Misty’s Navigation Module can be found in Misty’s developer documentation. As you experiment with these features, please refer to the tips below for best results.
Mapping Tips, Tricks, Dos, and Don’ts
- Most importantly, if you haven’t done so already, make sure to download and apply Misty’s 2020.01.07 Android patch for improved SLAM performance.
- Pay attention to the two-dimensional map in the Navigation Module while mapping, and drive Misty to new (“unknown”) areas as needed.
- Use the depth sensor’s fisheye camera to take and view a wide angle picture to make sure the visual picture isn’t backlit or washed out from too much light. If you can recognize features in the room from the picture, then Misty is likely to recognize those features, too.
- Drive at a consistent speed. For best results, we recommend using the Navigation Module’s default speed. Driving faster can cause Misty to lose pose.
- Spin Misty in open areas to quickly obtain the most coverage.
- When Misty turns on a smooth surface (such as a hardwood floor), the tracks tend to stick a little, which makes the turn a little wobbly. This is not ideal for mapping, so on these surfaces it’s sometimes best to turn Misty in an arc or perform an n-point turn, rather than just pivoting Misty or spinning her in place.
- Do not get too close to objects with a uniform appearance (i.e. a solid white wall or the back of a couch), as this can cause Misty to lose pose.
- For best results, the lighting in the environment where Misty is mapping / tracking should be consistent throughout the whole space.
- The depth sensor has a minimum working range of about 0.5 meters. Do not get closer than 0.5 meter to any object. For best results, we recommend staying about 1 meter away from all objects.
- Avoid black & shiny things. These are bad for both the depth sensor and for Misty’s vision capabilities.
- Mapping and tracking works by identifying features in the environment so that Misty can obtain and maintain pose. The SLAM system performs best in spaces with a lot of features (i.e. many edges, textures, changes in color, changes in shape, etc) vs. sparse areas with no features (i.e. near large, flat, mono-colored walls). Try to always have some objects with texture in view, especially when turning.
- If you’ve tried mapping or tracking and are are struggling to obtain or maintain pose, reset the sensor by clicking the Reset Sensor button. Wait for the values of the Sensor and SLAM status fields to be
Readyfor both sensors, and then try again.
- Drive slowly, and especially turn slowly. If you’re having trouble getting good results, try lowering Misty’s velocity to 15% of max speed when you turn the robot.
- Keep Misty’s head level, or about +5 degrees in the pitch direction. Use the Set Head button in the Navigation Module to set the head in a good orientation for mapping and tracking activities.
- When tracking, Misty can only relocalize well from similar viewpoints as the ones used to create the map. As an example, if you drive Misty clockwise while mapping around a table, Misty won’t be able to relocalize when she drives counter-clockwise around the table because she never actually saw the features of the room and table from that perspective. The solution is to drive Misty every which-way while mapping, so that Misty captures images from as many viewpoints as possible. Be aware, however, that currently Misty does have a limit on how long she can map due to memory. We’re actively working to improve this.