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2021 Primer on Dual High-Speed Video Recording of a Golf Swing

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  • 2021 Primer on Dual High-Speed Video Recording of a Golf Swing

    This topic has multiple entry threads going back years. I acknowledge pioneer Inor Kuo and folks behind Kinovea software (kinovea.org). Making dual high-speed video recordings of a golf swing is now much easier than it was a few years ago. This 2021 description updates and simplifies the procedure.

    Needed
    1. Two Video Cameras (requirements later. I use Daheng 1440 x 1080; 227 fps capable, monochrome with f/1.2 or 1.4 lenses - all important choices)
    2. Computer with two USB 3 ports
    3. Software: Kinovea (free download; Beta 0.9.3). Disregard older advice that the Beta does not work for the golf swing – it does now.
    No Longer Needed
    • Audio Zone Trigger – now built into Kinovea Beta
    • VLC Media Player (free download)
    • A separate microphone. I use my laptop microphone easily.
    Information below contains the following:
    1. Steps to Make Dual Recordings and Save to Sequential Files
    2. How to Review Kinovea Videos after Each Shot
    3. Equipment and Software
    4. Dual Video Recording with FSX 2020
    Steps to Make Dual Recordings and Save to Sequential Files
    1. Plug cameras into computer USB 3 ports.
    2. Start Kinovea program Beta 0.9.3.
      • Select two capture windows (“screens” in software, I use “windows” to avoid confusion with dual computer and projector screens of golf sims)
      • Open one camera on one window and the other on the other window. You should see real time videos, likely dark at first
      • Click top bar of each capture window to set camera acquisition: Exposure and Gain determine allowable frame rate. High frame rate makes bigger files and requires more buffer. To get 227 fps Exposure is under 4300 micro-seconds (1/framerate = 1/227 sec). My Gain with Exposure=4300 microseconds is 17-18 dB (out of max 24). Stop motion better with lower Exposure (e.g. 1000 microsec = 1/1,000 s) but more Gain (3 dB per doubling/halving). If I don’t need 227 fps, I set Exposure to 10,000; Gain to 8-10 for 100 fps (or 20,000 and 3 for 50 fps), so there are choices depending on requirements. A color camera needs 5 dB more Gain for a given shutter speed due to the color filter over the sensor.
    3. Set following Kinovea Options - Preferences
      • General Tab: allow multiple instances of Kinovea to review videos after each shot
      • Drawings Tab: tick Opacity box so drawings are visible for entire video
      • Most important settings are in Capture sub-menus:
        • Capture - General: Record uncompressed video (no time to compress); Uncompressed Video Format MKV.
        • Capture - Memory: Set Delay buffers. 1.5 GB allows 2 seconds delay each camera at 227 fps. Change here for other scenarios
        • Capture - Recording Mode DELAYED; I set high speed camera frame rate threshold = 235 with display framerate of 30
        • Capture - Video Naming: set for each camera Root Directory (e.g. Kinovea\Swing Videos folder in Documents); subdirectory for each day as %year-%month-%day; Video Name as e.g. “Rear 1” or “Front 1” (can be changed later; incremented automatically).
        • Capture - Automation CRITICAL: Enable Audio Trigger; choose input mic (I use laptop mic); set Threshold (start at 56); stop recording duration of 3.5 seconds; I check Ignore File Overwrite.
      • Save updated Preferences to remain as defaults.
    4. In each Capture Window, set Delay to 2 secs. Videos go into RAM buffer so impact activates sound trigger recording including the prior 2 seconds for a total of 3.5 seconds set in the Automation Tab of Capture Options. If buffer is too small, delay will be limited - must enlarge buffer. [To use cameras as two-way delayed “mirror”: turn off trigger and set delay to 4 seconds: then project video onto hitting screen , take swings and look to see two views at real speed 4s later.]
    5. In each Capture Window, make sure video saving labels for front and rear are correct for each camera. They easily get switched around depending on the order the computer found cameras or the order Kinovea connected. If starting a new session, with, e.g. a wedge, use “PW Front 1” and “PW Rear 1” in Capture Window Video Name boxes and they will be incremented after each save.
    Now swing and/or hit balls. You don’t have to do anything to Kinovea UNLESS you want to review videos for each shot – see later. THIS procedure rapidly saves a series of videos for subsequent examination. The later procedure is for looking at each video pair after each shot. Set up the computer for dual display and put Kinovea on the computer and your golf sim on the hitting screen and happily hit balls as long as HD space allows.

    If Trigger Threshold is too low, you may accidentally record unwanted 3.5 second clips. Usually the system carries on and numbering remains consistent. Once in a while, the two video file names get out of sync (e.g. “front 31” and “back 32”), so it is good to keep checking on capture windows.
    If Trigger threshold is too high, you can miss some swings like short wedges, so I set Options - Preferences - Capture - Automation Threshold to 25 for a series of short shots. For putting, speak loudly after the stroke.

    When you want to shut down, close Kinovea and unplug cameras.

    How to Review Kinovea Videos after Each Shot

    Best approach is to run two instances of Kinovea. Flipping back and forth from two capture windows to two playback windows in a single instance resets the Delay (sometimes video file name). To start 2nd instance I right click on Kinovea taskbar icon; select Kinovea.


    Equipment and Software

    Video Cameras

    Daheng MER2-160-227U3M cameras came from www.get-cameras.com. They are one of 3 types internally supported by Kinovea; 1/3 cheaper than others using Sony IMX273 sensor; global shutter for fast motion. With 10 ft USB 3 cables, tripod mount, CS lens mount, shipping, currency, duty and tax they cost Can $500 each. Options such as IO are not required. Get-cameras.com technical support is quick, thorough and effective.

    1440 x 1080 resolution and 227 FPS is the max combination of resolution and shutter speed to fill USB 3 carrying capacity. 1440 x 1080 allows zoom to see detail. U3M model is monochrome, but color U3C model is same $. Color needs 5 dB higher Gain (max is 24; I operate mono high speed at 18). 3.5s of uncompressed mono video at 227 fps is 1 GB. Color files may be larger. CHECK if it matters!

    Much cheaper and less functional cameras are available as discussed on older golfsimulatorform.com topics:Consult them for camera alternatives. Uneekor Swing Optix and Swing Catalyst use more expensive cameras based on the same Sony Sensor.

    Lenses
    Get-cameras.com does sell lenses but I got my CS mount lenses elsewhere: 2.8 mm f/1.2 (Can$12 from Alibaba) and 3.3-12 mm f/1.4. (Can$65 Arecont MPL33-12A from PC Canada). 3.8-4 mm suffices for cameras 8-10 ft from the golf swing (2.8 mm would work 4-5 ft away). All these lenses have some distortion (more with smaller focal lengths), so if accuracy is important to measure angles or distances, get a non-distortion lens (f-stop might go up to f/2.4). Low f number is important to limit Gain: f/2.4 vs f/1.4 costs 5 dB Gain. Color camera and f/2.4 lens might never achieve maximum frame rate. If frame rate is not important don’t buy these cameras.

    Lighting: My setup has 10,000 uneven lumens in a 20 x 20 ft room. Monochrome means I should wear medium tone clothing to separate myself from dark tones of green hitting mat.

    Monochrome CMOS Sensor IR sensitive: shows flashes from IR based Launch Monitors like GCQuad. Not good to aim a camera directly into GCQuad strobe.

    Computer: Dell G7 Gaming Laptop with 1 TB SSD, 16 GB of RAM, i7-10750H processor, Nvidia RTX 2060, built-in mic and 3 USB 3 ports.

    Software
    • Kinovea (free download from kinovea.org; Beta 0.9.3). Disregard older advice that the Beta does not work for the golf swing – it does now.
    • Daheng Galaxy (Free camera controller from Daheng or get-cameras.com). Use it to set Exposure, Gain and Focus before closing Galaxy and opening other software (e.g. FSX 2020) that can’t control the cameras. Two programs cannot demand access to the same cameras, so Galaxy must be closed after setting the parameters.
    Dual Video Recording in FSX 2020
    1. Using Kinovea or Daheng Galaxy open each camera and set the Exposure/Gain to achieve 30-60 fps. Close this program to release cameras
    2. Start up FSX 2020. Go to Setup Cameras menu. Refresh Cameras. Choose Cam 1. One of the options is Daheng 1 (first camera found by operating system) – choose it. Select the box for cam 2. I don’t know why Daheng Cam 2 is available (if you get DirectShowGX from get-cameras.com), but doesn’t show any image in FSX 2020. However, the laptop camera is available and could be used for front view. Select cam 2 and close Setup menu.
    3. Hit golf shots; videos are saved TEMPORARILY in Program Files (x86)\Foresight Sports Experience\Swing Videos as mp4 files YYYY_MM_DD_HH_MM_SS.00n where n is cam 1 or 2.
    4. Review videos for any shot within FSX 2020 during the session using normal shot analysis pages.
    5. To save videos, copy them elsewhere to avoid deletion BEFORE CLOSING FSX 2020. Foresight uploads videos to FSX Live (if connected), from where you can download them later. Save a round trip into cyberspace by copying them out before closing FSX 2020. Maybe someday Foresight will let us export directly from FSX 2020.

  • #31

    I'm considering setting up my own video recording in my training/sim space as described in the thread but a third, overhead camera (similar to Uneekor) for impact would be a nice addition.

    ​​​​​​​Anybody have experience with three cameras? If so, how is the memory and cpu usage when running those in conjunction with simulation? Not opposed to the idea of using one of my slightly older gaming rigs to run the recording software standalone but it would be convenient to have them all in the same place with the same data for reference and instructional purposes.

    Comment


    • #32
      Using a top camera that exactly is aligned on the center line of my system.
      The camera is an IDS-Camera 3140, having the Python 1300 color-sensor having a 15mm lens F1.2.
      You can see the pictures below that is an added picture of the single frames the camera is recording at a speed of 500fps.
      The maximal fps the camera can record at regular frame size is 165, but reduzing the height of the frame to 256 allows to increase the fps to even more than 500fps.
      Attached are also pictures using 200fps. However, what is more important is the shutter-speed. It is set to 500 microseconds to reduce blurring.
      Using such low values, you need a lot of light. I'm using 2 x 200W absolute flickerfree LEDs (using a dimmer to adjust the birghtness) and a 40W spot centered to the ball from the top.

      Comment on the cameras I use: (IDS 3140 Rev. 2, sensor: PYTHON1300, Color), Basler MONO 1440x1040 Sensor IMX273 Mono
      Due to high speed recording and more easy post processing of the videos I use MONO recording exclusively. The colors doesn't give further information to me.
      Under these conditions, the Basler needs much less light and results in more crips images. So the IMX273 Mono sensor is a good choice to me and affordable.

      Regarding the CPU it is difficult to say, not knowing your computer. I'm personally using the video analysis exclusively on the range (Skytrak). If I play a round on TGC, it rather disturbes me.
      My personal exprience is the following:
      1 recording Kinovea-Instance uses about 30% CPU-Load on an i5, 20% on an i9 (MONO)
      1 replay Kinovea-Instances uses about 5% CPU-Load (MONO)

      So on an i5, more than 2 high speed cameras may not be possible, except, you reduce the fps and frame size.
      On an i9/9900 I have 2 cameras at 200fps (about 1024/1024 framesize, front view and down the line) and 1 top camera 500fps (1024x256 frame size, Mono)
      Adding the Skytrak - Range the total CPU-load is about 70-80%.

      Below you can find some images of the top camera. It is very interesting what happens with the club during hitting the ball and how it results in the ball flight path. Sometimes it is really different than expected (at least to my knowledge).

      Reiner

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      Attached Files

      Comment


      • #33
        Trying to learn more about cameras. Does this one look like a good option? Seems so to me. I just don't know enough yet (especially about the lenses needed to capture a swing from about 10 ft).
        Buy Arducam 120fps Global Shutter USB Camera Board, 1MP 720P OV9281 UVC Webcam Module with Low Distortion M12 Lens Without Microphones, for Computer, Laptop, Android Device and Raspberry Pi: Shutter Release Cords - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

        Comment


        • #34
          I ended up getting the camera I asked about above. It works pretty well most of the time, but I'm getting some weird flickering. I can't quite figure out what's causing it yet. I can post a video later, but I was just wondering if anyone else has noticed anything similar with this camera. It doesn't quite seem like a lighting issue, but more of an issue with the camera itself. Not sure, though...

          Comment


          • bubbtubbs
            bubbtubbs commented
            Editing a comment
            Try it with an incandescent or halogen bulb and see if it still flickers. Might just be 60Hz nonsense.

          • PantsParty7
            PantsParty7 commented
            Editing a comment
            I'll play around with it some more, but the interesting thing was that I was seeing this flicker/glitch thing every once in a while with nothing but sunlight and a GC3. It was weird. That's what led me to believe it was an issue with the camera itself.

        • #35
          Would this be a decent camera for swing recording?

          UC10MPC_ND_BH36: 720P USB Global Shutter Monochrome Box Camera OV9281 with 95 degree non-distortion Lens (spinelelectronics.com)

          Comment


          • #36
            Anyone use this for swing recording? Impressions? How far behind/to the side would it need to be to capture a full swing?

            https://store.spinelelectronics.com/...YtZhQ3zPLREvJ_ xm6TdlZyuOlHOVtmdfQStHdad7lL_Vpkjc

            Comment

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