Reviewing and comparing fit artifacts

Complete guide to reviewing, analyzing, and comparing fit artifacts in Velogic Studio including videos, metrics, and stroke analysis

As you carry out the fit, Velogic Studio records various "artifacts" for each capture. These include:

• Raw videos from the depth camera(s) and/or any webcams you have at different positions around the rider.

• Stroke analysis videos from the depth camera(s), giving a higher virtual-frame-rate and the ability to scrub to particular crank angles

• Metrics calculated from the sensor data, e.g. body angles and movement from the Kinect camera, or ANT+ data from sensors on the rider or bike.

Velogic Studio makes it quick & easy to review and compare these artifacts, so that you can clarify the effect of changes in position - both for yourself, and to show your client what you're seeing & why you're making changes.

Hovering over thumbnails in the Fit Log

The quickest way to review a previous capture is simply to move your mouse over the thumbnail images in the Fit Log at the bottom of Step 2:

Fit Log thumbnails at bottom of Step 2 showing capture previews with mouse hover functionality

When you move the mouse over a thumbnail image for a particular capture, Velogic Studio will auto-play see the videos saved as part of that capture. The Motion Metriqs from that capture will be displayed on the right-hand side, and the title of that area will change from "Motion Metriqs" to the number and comment from that capture.

Because this is triggered by just a mouse move, if you move the mouse away, Velogic Studio will return to live mode.

Locking a capture for review

If you want to interact with the artifacts from a particular capture, just move the mouse over that capture's thumbnail (as above) and then click the "LOCK" button.

The appearance of that capture's thumbnail will change to show that it's now locked:

Locked capture thumbnail with changed appearance indicating review mode is active

...and you can then move the mouse off to interact, e.g. to scrub the videos or change into Stroke Analysis mode, or to click on a metric (see below).

Global playhead

When you're reviewing a capture (either by hovering over the thumbnail, or locking it for review) a global playhead will appear at the top of Step 2. You can use this to control all videos from a single place, and also to control things like the analysis mode (raw vs stroke) and the playback speed.

Stroke analysis mode

The default playback mode is Raw, which is just the realtime video recorded during the capture. But you can click the Stroke button in the global playhead to go into Stroke analysis mode. In that mode, the raw video will be replaced by Stroke Analysis video:

Stroke Analysis mode showing crank angle scrubber with 0°, 90°, 180°, 270°, 360° markers

Stroke Analysis is a detailed way to review a capture. There is still a scrubber bar at the top (just like for raw video), but there are some big differences. The horizontal axis of the Stroke Analysis scrubber does not represent time; instead, it represents crank angle. You can see labels for 0° (top of pedal stroke), 90° (~middle of power phase), 180° (bottom of stroke), 270° (~middle of recovery phase) and 360° (back to the top of the pedal stroke).

The small dots which appear along the horizontal axis each represent an individual frame, captured at that crank angle. Velogic Studio has automatically analysed all frames from the capture and re-ordered them to create a virtual-high-frame-rate video.

Note that because the frames have been reordered, if the rider was moving their head during the capture, their head will appear to "flicker" in the Stroke Analysis mode. You might want to ask your rider to fixate on a point and try to keep their head still during the capture to minimise this effect.

When you grab the scrubber and drag left/right, other videos from that same capture (e.g. if it was a bilateral capture) will move to the same crank angle.

Drawing tools and grid

Sometimes you want to draw on-screen to explain something to your client. If you click on the "DRAW" button at the top of the video, you'll see a drawing toolbar appear overlaid on the video:

Drawing toolbar overlay on video with annotation tools for client explanations

You can click on the border of the drawing toolbar to move it around within the video area. The tools on the toolbar are probably already familiar to you if you've used other drawing systems in the past, but here's a summary from left to right:

• The "selection" icon lets you draw a rectangle around drawings you've already made, so that you can move or delete them by clicking the Delete key on the keyboard

• The "angle" tool lets you draw an angle with 3 mouse clicks, and will show the degrees inside that angle (or the external angle if you hold the CTRL key). Note that the angle measured with these tools is a simple 2D measurement; if you were to try to use this tool to measure an angle reported as a MotionMetriq (e.g. knee angle), they are likely to be different - because MotionMetriq's are measured (more accurately) in 3D, using information from the depth camera.

• The "line" tool lets you draw a simple 1-segment line

• The "multiline" tool lets you draw a line made of multiple segments. You can double-click or press Enter to finish drawing.

• The "pencil" tool lets you draw completely freehand

• The "text" tool lets you draw textual annotation

• The "save" icon will save a snapshot of the drawing (and the current frame from the video) into the fit folder. It will ask for a name for the snapshot, and will save the snapshot into the fit folder. If you have the "Include annotated images" option turned on when you later generate the report, the snapshot will automatically be included in the report, along with the name you gave it.

• The "delete" icon will delete all drawing items.

• The "close" icon on the right will hide the drawing toolbar. The drawing items will remain on the screen; to remove them, you need you click the "delete" icon on the toolbar.

Clicking on the "GRID" button will overlay a "laser grid", so you can watch the movement against known-vertical and known-horizontal lines (in 2D):

Laser grid overlay on video showing vertical and horizontal reference lines

Focusing on one particular metric

You can click on any metric in the MotionMetriqs area:

MotionMetriqs panel with clickable metrics for detailed analysis

...and it will be highlighted with a "lock" symbol, and a number of things will happen:

• the fit log thumbnails (along the bottom of the screen) will have the value for that metric overlaid, so you can quickly see how it has changed between captures:

  

  Fit log thumbnails showing metric values overlaid for quick comparison between captures
• the visuals will automatically skip to the frame which best illustrates that metric (if appropriate)

• a visualization will be drawn on the frame, to illustrate the metric to you and your customer:

Video frame with metric visualization highlighting specific body measurement

There are many different visualizations available, here are some examples:

Joint angle visualization showing biomechanical angle measurement on rider

Lateral movement visualization displaying side-to-side motion tracking

Horizontal and vertical movement visualization showing directional motion analysis

Ankle swivel visualization demonstrating rotational movement measurement

See also:

• Ankle flexion metrics

• 

To stop focusing on that metric, just click it again in the MotionMetriqs panel to deselect it.

Comparing 2 different captures

If you already have one capture locked for review (see above), when you mouse-over a different capture you'll see a "Compare" button at the top:

Compare button interface for analyzing differences between two captures

If you click that "Compare" button, the layout of the visuals area will change to put the equivalent visuals from those 2 captures side-by-side, and you can scroll down to interact with each pair:

Side-by-side comparison view of two different captures with synchronized playback

Initially, the visuals will play in "raw" mode: just the actual video recorded during the capture period. But, if you click on the "Stroke" button at the top, or click on any of the MotionMetriqs, the videos will go into Stroke Analysis mode:

Stroke Analysis comparison mode with crank angle synchronized between two captures

... and because Stroke Analysis mode is based on crank angle, you can drag the scrubber bar at the top to move both sides with the crank angles synchronized.

In Stroke Analysis mode, there are also additional comparison modes available:

• Side-by-side (the default)

• Overlaid (image)

Overlaid comparison mode showing two positions superimposed for direct visual comparison

• Crossfade (video)

• Morph

The Crossfade and Morph visualizations both generate videos on-the-fly, for the crank angle you have selected. You can click "Save" to save the video as an .mp4 in the fit folder.

Checking and clearing lock or focus/compare state

When you've got a capture locked for review, and/or a second capture locked for comparison, and/or you're focusing on a body metric, the capture area will change:

This is helpful if you're confused about what state you're in, and also makes it easy to return to the default state. You can click the X button next to any of the indicators, or click the CLEAR ALL button to return to the default mode.

Reviewing with the Fit Log Grid

When you really want to drill into the changes between captured positions, you can pull up the Fit Log Grid by clicking on the button to the left of the fit log thumbnails, at the bottom of Step 2:

Fit Log Grid button located left of thumbnails for detailed data view

This will pull up the Fit Log Grid, so that the thumbnails (which were at the bottom of the screen) are now at the top of the screen, with all the data for each position shown underneath in a grid format:

Fit Log Grid view showing thumbnails at top with detailed metrics data below in table format

Numeric data (such as metrics) are shown with an indicator showing the change from the initial position.