Calibration review step

Understanding and reviewing calibration results in Velogic Studio v4, including 3D visualization of bike plane and camera alignment.

Calibration has always been a little mysterious in Velogic Studio. What do the points mean? How do you know if you took them in the right place?

Velogic Studio v4 now has a new step in the Calibration and Measurement wizards to show you the results of the Calibration step, so you can quickly see if you've completed the calibration correctly or not.

After you've taken the 5 calibration points, you'll see a new Calibration Review step:

3D calibration review visualization showing bike plane, pitch points, and camera alignment in interactive 3D space

This can look quite bizarre at first glance, but you will quickly become familiar with it and how to use it.

If you click anywhere on the main 3D image and move your mouse (while holding the mouse button down), you'll see that you can drag the 3D image viewpoint around:

You can also use the mousewheel to zoom, and the right mouse button to drag the camera position.

What you are looking at is a 3D "snapshot" of the bike in your studio, with a visualisation of how Velogic Studio is using those points to establish the relationship between the camera and the bike. Let's dig in!

The bike plane

The first 3 points taken during calibration form a triangle, and the triangle is used to establish the "plane" of the bike. This is represented as a blue square in the visualisation, and you should see that the blue square sits in line with the frame of the bike as you drag left/right:

If the blue square is on an angle, or doesn't seem to line up nicely with the bike, you should go back and redo the calibration.

The pitch points

The last 2 points taken during calibration form a line or bar, which is used to establish the "pitch" of the bike, relative to the camera.

Calibration review interface showing pitch points visualization with green and orange calibration markers on bike frame

If the bar doesn't look like it connects the 2 pitch points you took during calibration, you should go back and redo the calibration.

Ideal vs Actual cameras

When you first move onto this step of the wizard, the virtual 3D camera will be positioned as if at the front of the bike, looking along the bike. This is to allow you to quickly see if the bike plane looks correct.

You can click on different predefined camera viewpoints by using the links on the right-hand side of the screen:

Camera viewpoint selection panel showing options for Actual camera, Ideal Driveside camera, and other preset viewing angles

If you click on "Actual camera" and then "Ideal Driveside camera" (or "Ideal Non-Driveside camera", depending on which side your camera is on), you will see a slight change in the viewpoint:

The "ideal" camera position has been calculated by Velogic Studio, using the calibration points. The "ideal" camera should be:

• directly facing the bike plane (to adjust for yaw or roll of the bike, relative to the camera)

• rotated so that the pitch bar (between the two pitch points) is level from the camera's point of view.

This is really the heart of what the calibration system is doing; it's adjusting for any misalignment of the camera with respect to the bike, so that measurements are as accurate as possible.

To further illustrate this, if you click on the "Actual camera" link and then use the mousewheel to zoom out slightly, you will see a virtual representation of both the Actual camera and the Ideal camera in the 3D scene:

3D scene showing both actual and ideal camera positions relative to bike frame for calibration accuracy assessment

If the actual camera was perfectly positioned relative to the bike, the actual and ideal camera would overlay each other.

Checking calibration numerically

On the right-hand side of this step, you can see some numeric values which quantify the relationship between the camera and the bike:

Calibration numeric values panel showing quantified relationship measurements between camera and bike orientation

With practice, you will be able to tell whether these numbers match your expectations. If your camera was perfectly flat and level to the ground, and perfectly at right-angles to the bike, and the bike was perfectly upright on the ground and perfectly level - then these numbers would all be 0.

Note that it's OK for the numbers not to be zero; calibration establishes what those numbers are, so that the measurement process can adjust for them mathematically.

After reviewing calibration

Once you are happy with the calibration points, you can click "Finish" to finish the calibration, or click "Next" to continue (if you were calibrating before measuring).