The original method of Chroma compositing ‘Green Screen’ has been an age old method which has been used very extensively, but this method has its own shortcomings since it can’t add much details, also it is a time consuming process. Conventional green screen techniques pose several challenges for production teams such as preventing clothing & objects in the scene from matching the backdrop's colour, addressing additional motion blur during post-production and sometimes limiting the use of makeup on the actors to avoid glare. It is understandable that a company of Netflix's size would seek a faster and simpler method to capture composited content given the cost and time associated with these challenges.
They have devised an innovative technique for efficiently and more accurately removing green screen from scenes. This approach involves illuminating actors with bright magenta light while combining red and blue foreground lighting. This new green screening method utilizes Machine Learning codes and comes under the category of Artificial Intelligence driven technology as it works effectively to exploit the "blind spot" of digital cameras. The magenta lighting creates a near-perfect silhouetted green channel which greatly simplifies the elimination process during post-production.
This technology enables the green channel to display the actors silhouetted against a bright and evenly lit background as per the research abstract.
Although the film making process may appear strange and off-putting to the human eye because of these beams of lights but it makes perfect sense to a digital camera. The camera's sensors which record in red, green and blue channels can utilize this information to generate a green channel where the scene is practically perfectly silhouetted against the well-lit background. This effectively creates a flawless matte mask and makes it easier to replace the background.
This AI driven technology decides which parts of the frame should be retained and which need to be digitally removed or replaced. This method of green screening also allows the actors to wear colours that include green without "disappearing" as they would if the standard green-screen was used in the video.
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