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This page covers instructions on how to set up and use the Prime Color video camera.

Overview


Prime Color Camera

The Prime Color camera is a full-color video camera that can be synchronized to a mocap system to be used as a reference camera or that can be used to record synchronized high-speed and quality videos. The camera enables recording of high frame rate videos (up to 500 FPS at 480p) with resolutions up to 1080p (at 250 FPS) by performing onboard compression (H.264) of captured frames.
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eStrobe

When capturing high-speed videos, especially with shorter exposure times, it is important to provide sufficient lighting in order to obtain clear images. The eStrobe is designed to optimally brighten the image taken by a Prime Color camera. This is achieved by synchronizing the LED illumination on the eStrobe with the exposure and frame rate of the camera. This synchronization allow the LEDs to illuminate as bright as they can be when the Prime Color camera is exposing and also to save up power when it is not exposing. The Prime Color camera and eStrobe syncrhonize with each other through an RCA sync cable connection.
  • PrimeColor Overview eStrobe.png
  • PrimeColor Overview eStrobe2.png

Hardware Setup


Focus and F-Stop

A Prime Color camera can be equipped with either the 12mm F#1.8 lens or the 6mm F#1.6 lens. The 12mm lens is zoomed in more and is more suitable for capturing at longer ranges. On the other hand, the 6mm lens has a larger field of view and is more suitable for capturing at a wider angle. Both lenses have adjustable f-stop and focus settings, which needs to be optimized for capture:

  • F-Stop: It is recommended to set the f-stop to a low value to make the aperture size bigger. A lower f-stop value will allow in more light onto the imager, but will also decrease the camera's field of view.
  • Focus: For best image quality, make sure the lenses are focused on the target tracking area.

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Note for 6mm F#1.6 lens: When capturing 1080p images with 6mm F#1.6 lens, you may see vignetting in each corner of the captured frames due to imager size limitations.

Load Balancing

Data Bandwidth

Before going into details of setting up a system with Prime Color cameras, it is important to cover the topic of data bandwidth availability within the camera network. One Prime Color camera can transmit data at a rate of up to ~100 Megabytes-per-second (MBps), or ~800 Megabits-per-second (Mbps), at its maximum bit-rate. In comparison, a tracking camera in Object Mode outputs data at a rate less than 1MBps, which is several magnitudes smaller than the output from a Prime Color camera. A standard network switch (1 Gb switch) and network card only support network traffic of up to 1000 Mbps (or 1 Gbps). For this reason, when Prime Color camera(s) are used, they can take up a large portion, or all, of the available bandwidth, and extra attention to bandwidth use will be needed while first setting up.
If there is not enough bandwidth, captured 2D frames may drop out due to the bottleneck. Thus, when first setting up the system, take the bandwidth consumption into account and make sure an appropriate set of network switches (PoE and Uplink), Ethernet cables, and a network card is used. If a 1 Gb network/uplink switch is used, then only one Prime Color camera can be used at its maximum bit rate. If 2 or more Prime Color cameras are used, then either a 10 Gb network setup will need to be used, as shown in the following section, or the bit-rate setting on the cameras will need to be turned down. A lower bit-rate will further compress the image with a tradeoff on the image quality, which may or may not be acceptable depending on the capture application.
It is also important to keep an eye on the data bandwidth when recording with color cameras because the size of the Take file will be larger. For example, if you record a 10-second take with a data throughput of 1 GBps, the resulting TAK file will have 10 GB file size, and it can quickly fill up the storage device.

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Detecting Dropped 2D Frames

Every 2D frame drops are logged under the Status Log panel, and it can also be identified in the Devices pane. It will be indicated with a warning sign next to the corresponding camera. You may see a few frame drops when booting up the system or when switching between Live and Edit modes; however, this should only occur just momentarily. If the system continues to drop 2D frames, that indicates there is a problem with receiving the camera data. If this is happening with Prime Color cameras, try lowering down the bit-rate, and if the system stops dropping frames, that means there wasn’t enough bandwidth availability. To use the cameras in a higher bit-rate setting, you will need to properly balance out the load within the available network bandwidth.

Note: Due to the current architecture of our bug reporting in Motive, a single color camera will not display dropped frame messages. If you need these messages you will need to either connect another camera or an eSync into the system.

Cabling

One or Two Color Cameras

Prime Color cameras connect to the camera system just like other Prime series camera models. Simply plug the camera onto a PoE switch that has enough bandwidth available and it will be powered and synchronized along with other tracking cameras. When you have two color cameras, make sure they are distributed evenly onto different PoE switches so that the data load is balanced out.
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Multiple Color Cameras

When using multiple Prime Color cameras, we recommend connecting the color cameras directly into the 10-gigabit uplink switch, because such setup is best for preventing bandwidth bottleneck. A PoE injector will be required if the uplink switch does not provide PoE. This allows the data to travel directly onto the uplink switch and to the host computer through the 10-gigabit network interface. This will also separate the color cameras from the tracking cameras.
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eStrobes

The eStrobe is designed to receive exposure signals from a Prime Color camera via RCA cable connection and synchronize its illuminations to the camera exposures. Depending on the frame rate of the camera system, the eStrobe will vary its illumination frequency, and it will also vary its percent duty cycle depending on the exposure length. Multiple eStrobes can be daisy-chained in series by relaying the sync signal from the output port to the input port of another as shown in the diagram.


  • PrimeColor eStrobeSetup.png
  • PrimeColor eStrobeSetup2.png

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Power Requirement The amount of power drawn by each eStrobe will vary depending on the system frame rate as well as the length of camera exposures, because the eStrobe is designed to vary its illumination rate and percent duty cycle depending on those settings.

At maximum, one eStrobe can draw up to 240 Watts of power. A typical 110V wall outlet outputs 110V @ 15A; which totals up to 1650W of power. Also, there may be other factors such as restrictions from the surge protector or extension cords that are used. Therefore, in general, we recommend connecting no more than five eStrobes onto a single power source.

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Warning:

  • Please be aware of the hot surface. The eStrobe will get very hot as it runs.
  • Avoid looking directly at the eStrobe, it could damage your eyes.
  • Make sure the power strips or extension cords are able to handle the power. Using light-duty components could damage the cords or even the device if they cannot sufficiently handle the amount of the power drawn by the eStrobes.
  • The eStrobe is not typically needed for outdoor use. Sunlight should provide enough lighting for the capture.

Ambient Lighting Frequency

When capturing high-speed videos, brightness of the captured frames will vary depending on which type of ambient light source is used.

Indoor

If you are capturing indoors without the eStrobe, you will be relying on the ambient room lighting for brightening up the volume. It is important to note that every type of artificial light source illuminates, or flickers, at a certain frequency (e.g. fluorescent light bulbs typically flicker at 120Hz). This is usually fast enough so that the flickering is not noticeable to human eyes, however, with high-speed cameras, the flickering may become apparent.
When Prime Color captures at a frame rate higher than the ambient illumination frequency, you will start noticing brightness changes between consecutive frames. This happens because, with mismatching frequencies, the cameras are exposing at different points of the illumination phase. For example, if you capture at 240FPS with 120Hz light bulbs lighting up the volume, brightness of captured images may be different in even and odd numbered frames throughout the capture. Please take this into consideration and provide appropriate lighting as needed.

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Info: Frequencies of typical light bulbs

  • Fluorescent: Fluorescent light bulbs typically illuminate at 120 Hz with 60 Hz AC input.
  • Incandescent: Incandescent light bulbs typically illuminate at 120 Hz with 60 Hz AC input.
  • LED light bulbs: Variable depending on the manufacturer.
  • eStrobe: LEDs on the eStrobe will be synchronized to the exposure signal from the cameras and illuminate at the same frequency.

Outdoor

When capturing outdoors using Prime Color cameras, sunlight will typically provide enough ambient lighting. Unlike light bulbs, sunlight is emitted continuously, so there is no need to worry about the illumination frequency. Furthermore, the sun is bright enough and you should be able to capture high-quality images by adjusting only the f-stop (aperture size) and the exposure values.

Check Point

Now that you have set up a camera system with Prime Color, all of the connected cameras should be listed under the Devices pane. At this point, you would want to launch Motive and check the following items to make sure your system is operating properly.

  • 2D Frame Delivery: There should be no dropped 2D frames. You can monitor this under the Status Log or from the Devices pane. If frame drops are reported continuously, you can lower down the bit-rate setting or revisit the network configuration and make sure the data loads are balanced out (#Data Bandwidth).
  • CPU Usage: Open the windows task manager and check the CPU processing load. If only one of the CPU core is fully occupied, the CPU is not fast enough to process data from the color camera. In this case, you will want to use a faster CPU or lower down the bit-rate setting.
  • RAM Usage: Open the windows task manager and check the memory usage. If the RAM usage slowly creeps up to the maximum memory while recording a take, it means the disk driver is not fast enough to write out the color video from RAM. You will have to reduce the bit-rate setting or use a faster disk drive (e.g. M.2 SSD).
  • Hard Drive Space: Take files with color camera data can be quite large sometimes. It is possible to fill your hard drive quickly if recording lightly compress video data from multiple color cameras.

Camera Settings


When you launch Motive, connected Prime Color cameras will be shown in Motive, and you will be able to configure the settings as you would do for other tracking cameras. Open up the Devices pane, and select a Prime Color camera(s), and at the bottom of the pane, key properties that are specific to the selected color cameras will be listed. Optimizing these settings are important in order to capture best quality images without overflowing the network bandwidth. The key settings for the color cameras are image resolution, gamma correction, as well as image compression and data transfer rate settings, which will be covered in the following sections.

Camera Resolution

Default: 1920, 1080

This property sets the resolution of the images that are captured by selected cameras. Since the amount of data increases with higher resolution, depending on which resolution is selected, the maximum allowable frame rate will vary. Below is the maximum allowed frame rates for each respective resolution setting.

Resolution Frame rate
960 x 540 (540p) 500 FPS
1280 x 720 (720p) 360 FPS
1920 x 1080 (1080p) 240 FPS

Compression Mode

Default: Constant Bit Rate.

This property determines how much the captured images will be compressed. The Constant Bit-Rate mode is used by default and recommended because it is easier to control the data transfer rate and efficiently utilize the available network bandwidth.

Constan Bit-Rate

In the Constant Bit-Rate mode, Prime Color cameras vary the degree of image compression to match the data transmission rate given under the Bit Rate settings. At a higher bit-rate setting, the captured image will be compressed less. At a lower bit-rate setting, the captured image will be compressed more to meet the given data transfer rate, but compression artifacts may be introduced if it is set too low.

Variable Bit-Rate

Variable Bit-Rate setting is also available for keeping the amount of the compression constant and allowing the data transfer rate to vary. This mode can be beneficial when capturing images with objects that have detailed textures because it keeps the amount of compression same on all frames. However, this may introduce dropped frames whenever the camera tries to compress highly detailed images because it will increase the data transfer rate; which may overflow the network bandwidth as a result. For this reason, we recommend using the Constant Bit-Rate setting in most applications.

Bit-rate

Default: 50

Available only on Constant Bit-rate Mode

Bit-rate setting determines the transmission rate outputted from the selected color camera. The value given under this setting is measured in percentage (100%) of the maximum data transmission speed, and each color camera can output up to ~100 MBps. In other words, the configured value will indirectly represent the transmission rate in Megabytes per second (MBps). At bit-rate setting of 100, the camera will capture the best quality image, however, it could overload the network if there is not enough bandwidth to handle the transmitted data.

Since the bit-rate controls the amount of data outputted from each color camera, this is one of the most important settings when properly configuring the system. If your system is experiencing 2D frame drops, it means one of the system requirements is not met; either network bandwidth, CPU processing, or RAM/disk memory. In such cases, you could decrease the bit-rate setting and reduce the amount of data output from the color cameras.

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Tip: Monitoring data output from each camera Data output from the entire camera system can be monitored through the Status Panel. Output from individual cameras can be monitored from the 2D Camera Preview pane when the Camera Info is enabled under the visual aids (Viewport16.png) option.

Gamma

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