Is your ultra-HD TV value it? Scientists measure the decision restrict of the human eye

According to researchers on the University of Cambridge and Meta Reality Labs, the human eye has a decision restrict: in different phrases, there are solely so many pixels the attention can see. Above this restrict, a display offers our eyes extra info than they will detect.

To calculate the decision restrict, the researchers carried out a examine that measured members’ capability to detect particular options in color and greyscale photos on a display, whether or not wanting on the photos straight on or by way of their peripheral imaginative and prescient, and when the display was near them or additional away.

The exact decision restrict is determined by various variables, together with the scale of the display, the darkness of the room, and the gap between the viewer and the display. However, for an average-size UK front room, with 2.5 metres between the TV and the couch, a 44-inch 4K or 8K TV wouldn’t present any extra profit over a decrease decision Quad HD (QHD) TV of the identical measurement.

The researchers have additionally developed a free online calculator the place customers can enter the scale of their room and the size and determination of their TV to find out probably the most appropriate display for his or her house. Their results are reported in the journal Nature Communications.

Any shopper shopping for a brand new TV is bombarded with technical info from producers, all making an attempt to steer them that the show decision of their screens – whether or not Full HD, 4K or 8K – presents them one of the best viewing expertise.

And show decision is taken into account equally essential for the various different screens we use, on our telephones or computer systems, whether or not we’re utilizing them to take photos, watch movies or play video video games, together with video games in digital or augmented actuality. Even automotive producers are providing greater and better resolutions for in-car info shows and satnav screens.

“As large engineering efforts go towards improving the resolution of mobile, AR and VR displays, it’s important to know the maximum resolution at which further improvements bring no noticeable benefit,” mentioned first writer Dr Maliha Ashraf from Cambridge’s Department of Computer Science and Technology. “But there have been no studies that actually measure what it is that the human eye can see, and what the limitations of its perception are.”

“If you have more pixels in your display, it’s less efficient, it costs more and it requires more processing power to drive it,” mentioned co-author Professor Rafał Mantiuk, additionally from Cambridge’s Department of Computer Science and Technology. “So we wanted to know the point at which it makes no sense to further improve the resolution of the display.”

The researchers created an experimental set-up with a sliding show that allowed them to measure precisely what the human eye can see when taking a look at patterns on a display. Instead of measuring the specs of a specific display, they measured pixels per diploma (PPD): a measurement of what number of particular person pixels can match right into a one-degree slice of your visual view. Measuring PPD helps reply a extra helpful query than ‘how high is the resolution of this screen?’ Instead, it solutions the query ‘how does this screen look from where I’m sitting?’

The extensively accepted 20/20 imaginative and prescient normal, primarily based on the Snellen chart that will likely be acquainted to anybody who has ever had their imaginative and prescient checked, means that the human eye can resolve element at 60 pixels per diploma.

“This measurement has been widely accepted, but no one had actually sat down and measured it for modern displays, rather than a wall chart of letters that was first developed in the 19th century,” mentioned Ashraf.

Participants within the examine checked out patterns with very superb gradations, in shades of gray and in color, and have been requested whether or not they have been capable of see the traces within the picture. The display was moved in the direction of and away from the viewer to measure PPD at completely different distances. PPD was additionally measured for central and peripheral imaginative and prescient.  

The researchers found that the attention’s decision restrict is greater than beforehand believed, however that there are essential variations in decision limits between color and black-and-white. For greyscale photos seen straight on, the common was 94 PPD. For crimson and inexperienced patterns, the quantity was 89 PPD, and for yellow and violet, it was 53 PPD.

“Our brain doesn’t actually have the capacity to sense details in colour very well, which is why we saw a big drop-off for colour images, especially when viewed in peripheral vision,” mentioned Mantiuk. “Our eyes are essentially sensors that aren’t all that great, but our brain processes that data into what it thinks we should be seeing.”

The researchers modelled their outcomes to calculate how the decision restrict varies throughout the inhabitants, which is able to assist producers make choices which might be related for almost all of the inhabitants: for instance, designing a show which has retinal decision for 95% of individuals relatively than a median observer.

Based on this modelling, the researchers developed their on-line calculator, which allows individuals to check their very own screens or assist inform future shopping for choices.

“Our results set the north star for display development, with implications for future imaging, rendering and video coding technologies,” mentioned co-author Dr Alex Chapiro from Meta Reality Labs.

Reference:
Maliha Ashraf, Alexandre Chapiro, Rafał Okay. Mantiuk. ‘Resolution limit of the eye: how many pixels can we see?’ Nature Communications (2025). DOI: 10.1038/s41467-025-64679-2