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How to Calibrate RoboCap Cameras

Follow this guide to collect the camera and IMU recordings needed to calibrate your RoboCap, then upload them to the calibration website.

Calibration Overview

Before starting, here's what you need to know:

  • Cost: $3 per calibration run, per RoboCap, regardless of whether calibration succeeds or fails.

  • Processing time: Approximately 3 hours.

  • Results: You'll receive an email once processing is complete.

You'll need

  • Calibration board: Get a Tag6-500-55mm calibration board (500 × 500 mm). You can purchase a calibration board or download the PDF version for reference.

    • When ordering, specify:

      • Model: Tag6-500-55mm

      • Size: 500 × 500 mm

      • Pattern: 6 × 6 tags (55 mm each, with 16.5 mm gaps)

      • Material: Aluminum

  • Mounting surface: Secure the board upright on a stable, preferably plain white wall. Adjust its height to suit the person performing the calibration.

  • RoboCap: Make sure your device is powered and connected to a sufficiently charged power bank.

  • Lighting: Choose a well-lit area without glare or shadows on the board.

Calibration Process

1. Set Up the Calibration Board

  • Mount the calibration board securely on a flat, upright surface.

  • Adjust its height so you can comfortably face the center of the board.

  • Make sure the entire pattern is visible, well-lit, and unobstructed.

2. Prepare RoboCap

  • Connect RoboCap to its power bank and turn it on.

  • Hold RoboCap securely with both hands.

  • Point the cameras being calibrated directly toward the center of the board.

You'll record four separate videos at the following distances:

Recording

Camera Position

Distance

1

Front cameras

40 cm

2

Eye cameras

40 cm

3

Left side camera

100 cm

4

Right side camera

100 cm

Important: Measure the distance from the cameras, not your body. Reposition RoboCap for each recording so the correct cameras face the board.

3. Record the Calibration Videos

Record four separate videos, one for each camera position.

For each video:

  • Position RoboCap at the required distance.

  • Start recording.

  • Follow the demonstration video for that camera position, completing all seven movements.

  • Stop recording before moving to the next position.

Each recording should take approximately 2 minutes, with about 15 seconds per movement.

Recording 1: Front Cameras (40 cm)

Position the front cameras approximately 40 cm from the calibration board.

Recording 2: Eye Cameras (40 cm)

Position the eye cameras approximately 40 cm from the calibration board.

Recording 3: Left Side Camera (100 cm)

Position the left side camera approximately 100 cm from the calibration board.

Recording 4: Right Side Camera (100 cm)

Position the right side camera approximately 100 cm from the calibration board.

4. Collect IMU Calibration Data (2 Hours)

In addition to the four videos, you must collect 2 hours of IMU data while RoboCap remains completely still.

  • Place RoboCap on a flat, stable surface where it won't be disturbed.

  • Start recording and leave RoboCap completely still for at least 2 hours.

  • Stop recording after 2 hours.

Expected IMU Files

With a 10-minute recording segment duration, you'll collect:

  • 12 recording segments (approximately 10 minutes each).

  • 2 .db files per segment: one for the left IMU and one for the right IMU.

  • 24 .db files in total.

Important: Do not move or rotate RoboCap during this recording. Keep it connected to a sufficiently charged power bank throughout.

5. Save and Prepare Your Files

Once all recordings are complete:

  • Make sure recording has stopped.

  • Allow RoboCap to finish saving the files before disconnecting power.

  • Connect RoboCap to your computer and copy the calibration files.

Keep the .mp4 camera recordings and their corresponding .db IMU files together so you can identify them when uploading.

6. Open the Calibration Website

  • Go to https://calibrations.robocap.io/.

  • If this is your first time, click Sign Up to create an account. Otherwise, log in with your existing credentials.

  • Open the Devices tab.

  • Add your RoboCap using its 16-character device ID.

  • Select your RoboCap and open the Calibrate tab.

7. Upload Your Calibration Files

Under Calibration data, you'll find five sections. Click Choose files in each section to upload the corresponding recordings.

Files Required for Each Section

Section

Required Files

IMU intrinsics (data5)

All 24 IMU .db files from the 2-hour stationary recording

Front cameras + IMUs (data6)

Left and right front camera .mp4 files + both IMU .db files from Recording 2

Eye cameras + IMUs (data7)

Left and right eye camera .mp4 files + both IMU .db files from Recording 1

Left camera + IMUs (data8)

Left side camera .mp4 file + both IMU .db files from Recording 3

Right camera + IMUs (data9)

Right side camera .mp4 file + both IMU .db files from Recording 4

Examples of Files to Upload

Use the examples below to identify the correct files for each section.

1. IMU Intrinsics (data5)

Upload all 24 .db files from the 2-hour stationary recording:

  • 12 left IMU files

  • 12 right IMU files

Example files: robocap_segment1_imu_left.db, robocap_segment1_imu_right.db, through segment 12.

2. Front Cameras + IMUs (data6)

Upload 4 files from Recording 2:

  • robocap_segment1_video_left_front.mp4

  • robocap_segment1_video_right_front.mp4

  • robocap_segment1_imu_left.db

  • robocap_segment1_imu_right.db

3. Eye Cameras + IMUs (data7)

Upload 4 files from Recording 1:

  • robocap_segment1_video_left_eye.mp4

  • robocap_segment1_video_right_eye.mp4

  • robocap_segment1_imu_left.db

  • robocap_segment1_imu_right.db

4. Left Camera + IMUs (data8)

Upload 3 files from Recording 3:

  • robocap_segment1_video_left.mp4

  • robocap_segment1_imu_left.db

  • robocap_segment1_imu_right.db

5. Right Camera + IMUs (data9)

Upload 3 files from Recording 4:

  • robocap_segment1_video_right.mp4

  • robocap_segment1_imu_left.db

  • robocap_segment1_imu_right.db

Important: Each camera recording must include its corresponding left and right IMU files. Do not mix files from different recordings.

Actual filenames may vary depending on the recording segment.

8. Wait for Uploads to Complete

  • Wait for all selected files to finish uploading.

  • Check the upload progress shown below each section.

  • Confirm that every required file has uploaded successfully.

A green checkmark appears when a section has all its required files.

9. Start Calibration

Each calibration run costs $3 per RoboCap, regardless of whether it succeeds or fails.

Once all required files have been uploaded:

  • The Start calibration (v2) button will become available.

    Note: The button remains disabled until all required files are present.

  • Click Start calibration (v2) to begin calibration.

Calibration processing may take longer than 3 hours.

10. Receive Your Calibration Results

You don't need to stay on the website while waiting. Your calibration results will be sent to your email once processing is complete.

  • Successful calibration: You'll receive the calibration results.

  • Failed calibration: You'll receive a report explaining the issues found during calibration, along with recommendations on how to resolve them.

You can also check the results on the website:

  • Go to the History tab.

  • Find your calibration and check its status.

  • Click Results.

  • If successful, click Download as ZIP to download the calibration files.

The ZIP file will be saved to your computer's Downloads.

Note: If your calibration is still processing, check again later or wait for the email notification.

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