4K resolution
4K resolution, also called 4K, refers to a horizontal display resolution of approximately 4,000 pixels. Digital television and digital cinematography commonly use several different 4K resolutions. In television and consumer media, 38402160 (4K UHD) is the dominant 4K standard, whereas the movie projection industry uses 40962160 (DCI 4K).
4K resolution
The 4K UHD standard doesn't specify how large the pixels are, so a 4K UHD projector (Optoma, BenQ, Dell, et al.) counts because these projectors have a 2718×1528 pixel structure. Those projectors process the true 4K of data and project it with overlapping pixels, which is what pixel shifting is. Unfortunately, each of those pixels is far larger: each one has 50% more area than true 4K. Pixel shifting projectors project a pixel, shift it up to the right, by a half diameter, and project it again, with modified data, but that second pixel overlaps the first.