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1

A pixel is a collection of components. Traditionally these components are red, green and blue, with each of them taking 8 bits of data. As it is often advantageous to have memory aligned certain ways, these where sometimes packed into 32 bits of space each. This leaves 8 bits of extra data at the end of each pixel. As this is neither red, nor green, or ...


3

None of the other examples explain why it's alpha, though. It's from the expression in Alpha Compositing: where Ca and Cb are the two input colour values and Co is the output combined colour. Varying the alpha between 0 and 1 varies the colour between front and back composited images. (Image processing also has "gamma", but not "beta" as far as I know)


4

Alpha channels were actually invented by George Lucas's company Industrial Light & Magic (actually Alvy Ray Smith did most of the work while working there, who was previously employed by Xerox PARC - who we can thank for almost everything in modern computing!). Alpha channels, in addition to doing cool effects like transparent window, transparent ...


3

In many image format, A pixel is defined as a vector with 4 components. RGB and alpha. In the perspective of whole image, you can select only each component of the pixel, and this provides a series of values. If you want to process only one component, then you can select the comonent of all the pixels of the image, and this is usually called a channel. A ...


6

The term comes from the definition of "channel" that means a specific portion of a frequency spectrum. In this case, the red, green and blue components of a color are often referred to as "channels" (since red, green and blue light are portions of the visible light spectrum). Since alpha is another component of color in computer graphics (although not one ...


33

Digital colors can be made up of three components: red, green, and blue. Combine these together, and you get final color, eg. yellow is 100% red, 100% green and 0% blue. The fourth component is, as you mentioned, transparency. Together, these form the tuple RGBA (red, green, blue, alpha) which represent an image. Now, instead of pixels, think about it ...


3

All images have 1 or more "channels" of information. For example, the familiar RGB image type has 3 channels of information: Red, Green, and Blue. That is, every pixel in the image has 3 numbers associated with it (if each number is 8 bits, then that's a 24 bit image). Alpha can add a 4th channel of information (so a 4th number associated with each pixel, ...



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