How to measure distance using ARCore?

When using ARCore to measure distance, we primarily achieve this by creating and analyzing anchors in the virtual space. The entire process involves the following steps:

1. Initialize the ARCore session and configuration

First, initialize the ARCore session within the application. This step typically involves configuring the session to utilize required features, such as tracking the device's position and orientation.

java
Session session = new Session(context);
Config config = new Config(session);
config.setUpdateMode(Config.UpdateMode.LATEST_CAMERA_IMAGE);
session.configure(config);

2. Capture planes and add anchors

In ARCore, distance measurement is typically performed on planes identified within the user's environment. Once the application detects a plane, the user can create anchors between two points on that plane.

java
for (Plane plane : session.getAllTrackables(Plane.class)) {
    if (plane.getType() == Plane.Type.HORIZONTAL_UPWARD_FACING && plane.getTrackingState() == TrackingState.TRACKING) {
        Anchor anchor1 = plane.createAnchor(plane.getCenterPose());
        // User-selected second point
        Anchor anchor2 = plane.createAnchor(plane.getCenterPose().compose(Pose.makeTranslation(0.5f, 0, 0)));
        break;
    }
}

3. Calculate the distance between two anchors

Once two anchors are established, the distance can be measured by calculating the Euclidean distance between them. This is achieved by retrieving the positions of each anchor and computing the distance between these positions.

java
Pose pose1 = anchor1.getPose();
Pose pose2 = anchor2.getPose();

float dx = pose2.tx() - pose1.tx();
float dy = pose2.ty() - pose1.ty();
float dz = pose2.tz() - pose1.tz();

float distanceMeters = (float) Math.sqrt(dx * dx + dy * dy + dz * dz);

4. Update UI or provide feedback

Finally, the measured distance can be used to update the user interface or provide feedback to the user. This can be done through simple text display or more complex graphical representations.

java
textView.setText("Distance: " + distanceMeters + " meters");

Example:

For example, in an AR measurement tool application, users can select the corners at both ends of a room as anchors. ARCore calculates and displays the distance between these two points, assisting users in understanding the room's length.

Summary:

Through the above steps, we can effectively use ARCore to measure the distance between two points in an augmented reality environment. This technology can be widely applied in fields such as interior design, interactive gaming, and education.