A pixel is the smallest unit of a digital image or display, representing a single point of color. Pixels collectively form the grid that makes up the visual output on screens, with their density and arrangement determining the resolution and clarity of the image.
Compositing is the process of combining visual elements from separate sources into a single image, creating the illusion that all those elements are parts of the same scene. It is widely used in film, photography, and graphic design to create complex imagery that would be impossible or impractical to capture in a single shot.
An alpha channel is a component of an image file that contains transparency information, allowing for complex image compositing by specifying which parts of the image should be transparent or semi-transparent. It is commonly used in digital graphics to overlay images seamlessly onto different backgrounds without unwanted artifacts.
Premultiplied alpha is a technique in computer graphics where the color values of an image are multiplied by the alpha value before being blended with the background. This reduces computational complexity and prevents artifacts when dealing with transparency in image compositing.
Image Matting is a process in computer vision that aims to accurately separate a foreground object from its background, essential for tasks like creating photorealistic composites. It involves estimating an alpha matte that represents the opacity of the foreground object, which becomes complex especially in the presence of fine details like hair or smoke.
Alpha matte extraction is a fundamental process in digital compositing that isolates the foreground from the background by creating an alpha channel. This technique enables seamless integration of different visual elements, allowing complex image or video compositions to be created with precision and flexibility.
Non-Premultiplied Alpha, also known as 'straight alpha', is a method of representing image transparency where the RGB color values are stored separately from the alpha channel, allowing for more flexible compositing operations. This representation can lead to artifacts when blending, necessitating careful handling compared to premultiplied alpha, which pre-multiples the RGB by the alpha value.