4K upscaling: Everything you need to know about how TVs turn HD into 4K

4K TVs are everywhere – and they're getting bigger. Over the past few years, there's been a resolution revolution as Full HD TVs have become virtually extinct in the face of new, improved 4K TVs. 

From being a cutting-edge new tech a few years ago, 4K TVs are now the mainstream, accounting for nearly 50% of all TVs shipped worldwide. Each has a resolution of 3,840x2,160 pixels, which equates to eight megapixels. That's so much more detailed than the paltry two megapixels offered by Full HD TVs. 

Why do we need 4K upscaling? 

There's a 'content gap'. Although we're now firmly in the 4K TV era, we're certainly not all watching 4K content, and full HD image

on a 4K panel won't look better, just bigger, without some clever upscaling.

"If you've got a full HD picture coming into the TV and if you didn't upscale it, it would take up just a quarter of the screen,

It would be then surrounded by an empty screen. What the upscaling process does it to ensure that the picture fills the

4K resolution of the screen."  

"The picture first comes into the TV from broadcast, Blu-ray, streaming service, whatever, and it gets analyzed for quality,

used to compare how different elements of that picture should look, and once that evaluation is done, the picture is upscaled

to what we say is 'near 4K' quality." 

"If you've got a full HD picture coming into the TV and if you didn't upscale it, it would take up just a quarter of the screen, "It would be then surrounded by an empty screen. What the upscaling process does it to ensure that the picture fills the 4K resolution of the screen."  

How does 4K upscaling work? 

There are various steps involved in adapting an HD picture for a 4K display. "It begins with an analysis of the signal received to determine what type and resolution it is – live TV or streaming, HD or full HD,Then comes the noise reduction. Edges, textures and details are then analyzed and sharpened accordingly. Finally, the signal is converted to 4K to match the native panel resolution." It's an incredibly involved process that requires powerful processors. 

"When you're upscaling from Full HD to 4K there is a lot of guesswork, and what we're trying to do it to remove as much of the guesswork as possible like other picture processors, upscales at a pixel level. "It doesn't just look at the pixel in isolation, it looks at the pixels around it, and on each diagonal, and also it will look up the pixels across multiple frames, to give a consistency in the picture quality. It's also critical for upscalers to be able to tell the difference between detail and noise/Mpeg artifacts, as there's no use in upscaling the latter. Upscalers also seeks to improve local contrast and color within video.