[justin_]

> Light is integrated over a finite area to form a singke color sample. During Bayer mosaicking, contributions from neighbouring pixels are integrated to form samples of complementary color channels.

Integrated into a single color sample indeed. After all the integration, mosaicking, and filtering, a single sample is calculated. That’s the pixel. I think that’s where the confusion is coming from. To Smith, the “pixel” is the sample that lives in the computer.

The actual realization of the image sensors and their filters are not encoded in a typical image format, nor used in a typical high level image processing pipelines. For abstract representations of images, the “pixel” abstraction is used.

The initial reply to this chain focused on how camera sensors capture information about light, and yes, those sensors take up space and operate over time. But the pixel, the piece of data in the computer, is just a point among many.

[glitchc]

> Integrated into a single color sample indeed. After all the integration, mosaicking, and filtering, a single sample is calculated. That’s the pixel. I think that’s where the confusion is coming from. To Smith, the “pixel” is the sample that lives in the computer.

> But the pixel, the piece of data in the computer, is just a point among many.

Sure, but saying that this is the pixel, and negating all other forms as not "true" pixels is arbitrary. The real-valued physical pixels (including printer dots) are equally valid forms of pixels. If anything, it would be impossible for humans to sense the pixels without interacting with the real-valued forms.

[SAI_Peregrinus]

IMO Smith misapplied the term "pixel" to mean "sample". A pixel is a physical object, a sample is a logical value that corresponds in some way to the state of the physical object (either as an input from a sensor pixel or an output to a display pixel) but is also used in signal processing. Samples aren't squares, pixels (usually) are.