To Set Up a Chroma Key

Set up the chroma key with the source you want to use and adjust the parameters.

Tip: Once you have set up the chroma key how you want it to appear, you can press and hold CHROMA KEY and press the KEY MEM button to store these settings and the key source. Pressing the KEY MEM button again will recall these settings for the chroma key. The Chroma Key Mem Use Personality Option selects how the key memory works for chroma keys.
  1. Press the SEL button on the Keyers module for the key you want to set up and select a video source on the Key bus.
    Tip: The SEL button allows you to quickly select the keyer you want to work with and assign the Key bus to the keyer. On the Double-Down control panel, the top button row is assigned to the even numbered keyers (2,4,6) and the button row below is assigned to the odd numbered keyers (1,3,5). This can be changed with the DD Key Delegation personality option.
  2. Press CHROMA KEY.
    Tip: On the TouchDrive panel you can tap the display segment for the key you are setting up. This displays the current settings for that key. You can tap any of these setting to have the menu follow to those settings.
  3. Press the Color button (Red, Magenta, Blue, Cyan, Green, Yellow) for the color of the background you are using for your chroma key.
  4. Press Initialize Key.

    The chroma key engine initializes and attempts to remove the selected background color from the video. Any further adjust is only required if you want to adjust aspects of the key.

  5. Press the Key Type button for the chroma key mode you want to use.
    • Wedge Key — Based on the standard chroma keyer and discriminates between the color vector angle and level of the background color vs the color vectors and levels in the foreground components.
    • Detail Key — Differs from the standard chroma keyer in that it adds luminance dependency to a three-dimensional spherical color discriminator.
    • Combination Key — Combine the two modes to offer good capture of high luma detail in the edge regions as well as compensation for similar foreground and background levels.
    Note: All adjustments are always available, even if they are not applied by the selected mode.
    Tip: Although adjustment can be made to either key type while the combined output is selected, it is recommended that adjustments of either key type be conducted with only that key type selected. This eliminates the possibility of the combined key type hiding or concealing the result of adjustments.
  6. Press Detail Key and adjust the Detail Key Parameters as follows:
    Tip: The Detail key type is layered over the Wedge key type and has the largest contribution to the final key-edge quality.
    • Clip — use this setting to clip between the foreground and background. You are looking to achieve complete background removal.
      Tip: Clip should be set to the point where the background is just removed. Setting it too high will reduce edge quality.
    • Gain — use this setting to lift the fill image. You are looking to achieve solid fill content.
      Tip: Setting the gain too high may introduce dark boundaries.
    • Shadow Sensitivity — use this setting to adjust the level of dark image areas, particularly in cast shadow areas.
    • Shadow Density — use this setting to adjust the apparent lightness of the dark / shadow areas in conjunction with the Shadow Sensitivity.
    • Highlight Sensitivity — use this setting to fill areas with specular highlights, such as reflective surfaces, that can show through to the background.
  7. Press Wedge Key and adjust the Wedge Key Parameters as follows:
    • Gain — use this setting to set the Angle Control to 100 and the Lift to 0 and then adjust this setting until the background is fully removed, leaving a reasonable edge to the key. Too much gain will produce hard and undesirable edges.
      Tip: Adjust the Gain with the Bkgd Luma Suppress to balance between background removal and edge quality.
    • Bkgd Luma Suppress — use this setting to compensate for uneven color or lighting in the shot to ensure the chroma background is fully suppressed.
      Tip: Turn on a box mask in the keyer you are using to view the chroma key output to compare the backgrounds. The masked area shows the background source without the key settings applied.
    • Angle — use this setting to change the color wedge angle (wedge shape) that is used to detect areas of foreground (fill) and background (alpha) based on the chosen color vector. This can help fill in areas of heavy spill without hardening edge detail.
    • Lift — use this setting to amplify the generated alpha signal to fill in areas of transparency.
    • Highlight Correction — use this setting to lift areas of the image might contain high luminance levels at edge boundaries. This could be due to lighting conditions, camera setup, or subject.
  8. Adjust the Global Parameters as follows:
    • Spill Suppression — use this setting to select the fill color that has been detected as color spill. You should not have to adjust this setting.
    • Edge Luma — use this setting to offset the detected level of the chroma background and allow for fine tuning.
      Tip: Press Auto Edge Luma to have the switcher automatically adjust the edge luminance based on the Measurement Src selection.
      Tip: If the subject image contains fine detail such as fine hair with a luminance level that is close in value to the chroma set color background level – it may be difficult to provide good separation between background and foreground elements.
    • Edge Softness — use this setting to filter the edges to eliminate undesirable hard edges and add realism to a scene by simulating depth of field characteristics.
    • Re-Spill — use the Re-Spill Color and Re-Spill Sat settings to select a color that is near the average color of the background/lighting that needs to be added into those areas of the fill that contain the spill from the chroma set.
      Tip: Press Auto Re-Spill Color to have the switcher automatically adjust the re-spill colors based on the Measurement Src selection.
  9. Use the automatic adjustments as follows:
    Tip: The Auto Adjust allows you to have the chroma keyer continuously measure the replacement background, the background you are keying the subject onto, used in the final composite.
    • Use the Measurement Source knob to select the video source that you want to place the chroma key over. This source is used for the automatic adjustment of the chroma key.
    • Press Auto Edge Luma to have the edge luminance automatically adjusted, based on the replacement background.
    • Press Auto Re-Spill Color to have the re-spill color automatically adjusted, based on the replacement background.