Sony Pixel Power calrec Sony

Eliminating Artifacts when Shooting LED Video Screens: Global Shutter Camera Technology

06/11/2020

--

Most of us have seen slowly-moving dark bands or thin lines when shooting video with large LED displays in the frame. The LED screen could be the focus of the shot or just in the background, but either way, these unwanted artifacts detract from the visual experience and vary in size, number, intensity, and movement depending on multiple factors. Most of these artifacts are caused by the type of imagers used in the cameras. Modern video and still cameras use CMOS sensors to capture images, and most have been rolling shutter CMOS imagers. In this article, we will discuss the advantages of the latest development in CMOS sensors - global shutter - and how global shutter imagers can greatly reduce or eliminate LED display artifacts.

The Evolution of the Solid State Imager

The original solid state imager was the Charge Coupled Device (CCD), which was developed back in the early 1970s. CMOS sensors are digital devices and were developed in the late 1990s. Today, all solid state imagers use electronic shutters to control their exposure time. The primary difference between CCD and CMOS imagers is that CCDs are analog rather than digital and were (effectively) global shutter devices. All CMOS imagers were rolling shutter devices until recently. Rolling shutter CMOS sensors provide good performance with low noise, and they also cost less to manufacture, which helps keep camera costs down.

Manufacturing costs for CMOS global shutter imagers are higher, as there's a lot more circuitry at each pixel to store and process the readout of the image. Most global shutter HD production or broadcast cameras are also full progressive scan (1080p60). But if you're shooting in an LED environment, the benefits of global shutter are generally worth the extra cost.

Why are Global Shutter Cameras Needed Now?

The use of LED displays and LED lighting can create temporal artifacts, which are commonly perceived as flickering. This is particularly the case with the increasing use of lower-cost LED displays, screen processors and lighting. LEDs are controlled by image refresh frequency, along with Pulse Width Modulation (PWM) frequency for brightness. The relative frequencies of the LED screen refresh rate and PWM compared to the camera's shutter frequency can cause visible artifacts such as flicker, rolling dark bands or thin lines. They can also cause skew - image curving or bending that is caused by fast- moving objects or fast camera movement during the acquisition time of rolling shutter imagers.

The human visual system has a powerful and unique capability called persistence of vision, which allows all these sorts of artifacts to appear normal to our eyes when seen directly. However, rolling shutter cameras acquire images in a way that causes them to see these LED flicker artifacts during acquisition.

Rolling Shutter Image Acquisition

Rolling shutter imagers acquire the pixels in each line of the video frame sequentially. This usually occurs over the frame rate of 59.94 Hz. During this time, the LED display refresh frequency and PWM are varying the brightness of the image as shown by the green pulses in the diagram below. Some lines are displaced in time and will have different brightness from other lines. The image's line readout takes place at the end of each line. When of all the sequentially acquired lines are delivered as a single video frame to the TV or monitor display, this shows as bands of varying brightness. This banding may occur when shooting with LED video displays, LED lighting, or both.

Global Shutter - Image Acquisition

In this context, the term global means all-inclusive, and refers to the fact that global shutter CMOS imagers acquire the entire video frame in one instant. The entire frame is stored in the imager's memory buffer for sequential readout, and the individual line readouts then proceed over the frame time, usually 59.94 Hz. Any difference in timing between the imager's shutter speed and the LED refresh rate (green pulses) is compensated by adjusting the camera's shutter to be an even multiple of the LED's refresh rate. This eliminates moving horizontal banding or lines in the picture.

To help you further visualize the difference between rolling shutter and global shutter imaging, please see the animated video at www.hitachikokusai.com/ShutterAnimation.

Moir

Moir artifacts are generally independent of the imager's shutter type and occur with both video and still cameras. When shooting any pixel-based display or LED video wall, moir is when odd stripes and patterns appear in your images. It occurs when a finely detailed pattern on your subject meshes and conflicts with the pixel pattern of the imaging sensor in the camera, causing viewers to see a third, separate pattern.

There are several ways to control moir . The easiest may be to simply reframe the shot by slightly zooming in or out to change the relative patterns. You can also reduce the image sharpness of the captured LED display by repositioning the screen further in background. Opening the iris has a similar effect by reducing the depth of field, putting the LED screen slightly out of focus behind the subject. You can even use a diffusion filter in front of the lens to slightly reduce camera resolution.

LED Screens and Video Display Processors

When selecting LED displays, screen processors and cameras, be sure to thoroughly test the selected LED display and screen processor with the camera exactly as you plan to use them, before you purchase anything.

Inexpensive LED displays are like most everything else: you get what you pay for. High quality LED screens offer better DC stability, better matching of the individual LEDs, and the capability of higher refresh and PWM frequencies. Higher frequencies reduce flicker.

Like the LED screens themselves, using a hi
LINK: https://news.creativecow.net/story/902035...
See more stories from creativecow

Most recent headlines

06/10/2025

France Tlvisions Wins Prestigious 2025 EBU Technology & Innovation Award in Groundbreaking Collaboration with Dalet

France T l visions, France's leading broadcaster, has received the 2025 EBU ...

04/09/2025

Monumental Sports & Entertainment and Dalet Win Prestigious 2025 NAB Show Project of the Year Award

Monumental Sports & Entertainment (MSE), in collaboration with Dalet, has been a...

16/06/2025

Give Me the Backstory: Get to Know Carmen Emmi, the Writer-Director of Plainclothes

By Bailey Pennick One of the most exciting things about the Sundance Film Festi...

16/06/2025

Spotify's Brian Berner on Creativity, Connection, and What's Next for Advertisers at Cannes Lions

The Cannes Lions International Festival of Creativity is officially underway for...

16/06/2025

Francophone Content on Spotify Continues to Thrive Around the World

On Spotify, francophone content continues to cross borders at an unprecedented rate. In 2024 alone, more than 123 million listeners worldwide streamed audio con...

16/06/2025

Tegna Announces Major Expansion of Local News Programming

TYSONS, Va. Tegna Inc. is embarking on a notable expansion of their already substantial local news programming by launching live and on-demand, local newscasts ...

16/06/2025

Netflix Expands Programmatic Ad Sales with Yahoo DSP

Netflix has announced that it is expanding its global programmatic ad offerings by partnering with Yahoo DSP. This will enable brands to buy Netflix advertising...

16/06/2025

Sub51 & Soundtrax announce Drop Pad 3

Instrument now boasts full NKS support Sub51 and Soundtrax have just announced the launch of an updated and improved version of their innovative sample-base...

16/06/2025

Roku, Amazon Team Up to Dominate CTV Ad Market

NEW YORK In a landmark agreement to overtake the burgeoning connected TV (CTV) advertising market, Amazon Ads and Roku today announced a new integration that gi...

16/06/2025

EdgeBeam Wireless Names Conrad Clemson CEO

ATLANTA, BALTIMORE, CINCINNATI and IRVING, Texas The four major broadcast groups behind the ATSC 3.0-based EdgeBeam Wireless datacasting joint venture today nam...

16/06/2025

Amazon MGM Studios to Deploy Avid Tools on AWS

BURLINGTON, Mass. Avid today announced an extended agreement with Amazon MGM Studios to integrate Avid's Media Composer and Avid NEXIS on Amazon Web Service...

16/06/2025

Maxon Epic Sale Drops June 16

Maxon, maker of powerful, approachable software for creators working in 2D and 3D design, motion graphics, visual effects, gaming and more, today announced the ...

16/06/2025

Alfalite launches Skypix a new ceiling-mounted Led panel...

Alfalite, the only European manufacturer of LED displays, announces the launch of SKYPIX RGBW & IM, a new series of ceiling-mounted LED panels designed specifi...

16/06/2025

ALM/Busy Circuits launch Pip Filter & LFO

Two new compact 4HP modules introduced ALM/Busy Circuits have just announced the launch of two new Eurorack modules, the Pip Filter and Pip LFO, both of whi...

16/06/2025

VEON Announces USD 35 Million Share Buyback

16 Jun 2025 VEON Announces USD 35 Million Share Buyback Announcement marks the third phase of USD 100 million share buyback program Dubai, June 16, 2025: VEON...

16/06/2025

Summer Sale: Big Discounts on Ivory II Pianos - Now Through June 30th!

Save 40% or More on All Ivory II Collections!From now through June 30th, enjoy huge savings on all Ivory II Piano Collections. Our biggest discounts ever are be...

16/06/2025

Behind The Broadcast Booth, Ep. 3: Golf. My Future. My Game. Founder and CEO Craig Kirby Talks Advocacy in Sports and More

Behind The Broadcast Booth, Ep. 3: Golf. My Future. My Game. Founder and CEO Cra...

16/06/2025

The REMI Revolution Is Here: How Remote Production Technology in Esports Pioneers a New Age of Broadcast

The REMI Revolution Is Here: How Remote Production Technology in Esports Pioneer...

16/06/2025

From Super Bowl to Indy 500, New Orleans Artist Frenchy' Captures Energy of Sports Production on Canvas

From Super Bowl to Indy 500, New Orleans Artist Frenchy' Captures Energy of...

16/06/2025

NFL Films Enhances Post Studio With Dolby Atmos Audio

NFL Films Enhances Post Studio With Dolby Atmos Audio Forty-three channels of audio enable the facility to migrate to immersive By Dan Daley, Audio Editor Mo...

16/06/2025

SVG New Sponsor Spotlight: Storj's David Colantuoni on Expanding Cloud-Based Storage to Live Sports Production

SVG New Sponsor Spotlight: Storj's David Colantuoni on Expanding Cloud-Based...

16/06/2025

Grass Valley 4K Cameras Head to Greece for View Master Events' New OB Truck

Grass Valley 4K Cameras Head to Greece for View Master Events' New OB Truck By Ken Kerschbaumer, Editorial Director Monday, June 16, 2025 - 2:33 pm Pri...

16/06/2025

WWF and Sky Kids launch Wear it Wild with Ready Eddie Go!

Monday 16 June 2025 Families and children are invited to dress up, have fun and raise money to protect nature WWF UK and Sky Kids are teaming up to launch Wea...

16/06/2025

The Rohde & Schwarz R&S M3AR radio family reaches 10,000 unit milestone, demonstrating commitment to innovation and quality

The Rohde & Schwarz R&S M3AR radio family reaches 10,000 unit milestone, demonst...

16/06/2025

FOX Advertising Launches Enhanced Brand Storytelling Program with Strategic Investment in The Lighthouse

FOX Advertising Launches Enhanced Brand Storytelling Program with Strategic Inve...

16/06/2025

Run With Ray in Cork, Waterford, Kilkenny, Drogheda and Dublin as The Ray D'Arcy Show hits the road

Run with Ray is back! RT Radio 1's The Ray D'Arcy Show hits the road th...

15/06/2025

Music Production for Women free in-person workshops

July 2025 in Dublin, Berlin, Amsterdam & London Photo: Thea Martre Music Production for Women (MPW) have announced that they will be running a series of fo...

15/06/2025

Jason's Piano & API Drums instruments from Sulcata Sound

Composer/producer launches free virtual instruments Sulcata Sound is the latest venture of Jason Graves, a two-time British Academy Award-winnning composer,...

14/06/2025

Pluto TV Adds All Womens Sports Network's FAST Channel

NEW YORK Pluto TV and the All Womens Sports Network have launched a free ad-supported streaming TV (FAST) AWSN channel in the U.S., Canada, the U.K. and the Nor...

14/06/2025

Scripps Inks Multiyear Agreement for WNBA Games on Ion

NEW YORK and CINCINNATI E.W. Scripps has announced a new, multiyear agreement with the WNBA that will continue Ions regular-season coverage of the league on Fri...

14/06/2025

NAB Highlights Hidden Importance of Spectrum in Major Sports Broadcasting

WASHINGTON The National Association of Broadcasters highlighted the hidden importance of spectrum in the production of major sporting events and described wha...

14/06/2025

1.0 Sunset, BPS and NextGen Broadcast's Potential Dominate ATSC Meeting

WASHINGTON Sunsetting ATSC 1.0, expanding business opportunities for NextGen Broadcast and increasing international adoption of the ATSC 3.0 standard were top o...

14/06/2025

Samba TV and Acxiom Announce Massive 40-market Global Expansion

SAN FRANCISCO Samba TV and Acxiom have announced that they will dramatically expand their longstanding relationship....

14/06/2025

MPW announce free in-person workshops

July 2025 in Dublin, Berlin, Amsterdam & London Photo: Thea Martre Music Production for Women (MPW) have announced that they will be running a series of fo...

14/06/2025

San Francisco State University's School of Cinema Uses Blackmagic Design

San Francisco State University's School of Cinema Uses Blackmagic Design Brie Clayton June 13, 2025 0 Comments More than 40 Blackmagic Design came...

14/06/2025

Boris FX Mocha Pro Adds New AI Tools To Tackle VFX Tasks Fast

Boris FX Mocha Pro Adds New AI Tools To Tackle VFX Tasks Fast Jessie Electa Petrov June 13, 2025 0 Comments The 2025.5 release helps artists work more...

14/06/2025

AJA Debuts DRM2-Plus Mini-Converter Frame at InfoComm 2025

AJA Debuts DRM2-Plus Mini-Converter Frame at InfoComm 2025 Brie Clayton June 13, 2025 0 Comments Next-gen frame addresses diverse rackmount needs wit...

13/06/2025

Prime Minister: A Behind-the-Scenes Look at a Leader Who Champions Kindness

(L-R) Lindsay Utz, Michelle Walshe, and The Right Honourable Dame Jacinda Ardern attend the 2025 Sundance Film Festival premiere of Prime Minister at Eccles T...

13/06/2025

Materialists' Director Celine Song Reveals the Inspirations Behind the Film's Soundtrack

Photo credit: Atsushi Nishijima If you're a true lover of rom-coms, chances...

13/06/2025

Pure Drama and Fierce Rivalries set to dominate the world's most iconic sporting event

Pure Drama and Fierce Rivalries set to dominate the world's most iconic spor...

13/06/2025

Press Release: NFVF Opens Call for Public Film Screenings on GBV Awareness as South Africa Confronts Ongoing Femicide Crisis

Johannesburg, 12 June 2025 - The National Film and Video Foundation (NFVF), an a...

13/06/2025

Central Texas Storm Knocks out KTXS Tower, Severely Damages Building

ABILENE. Texas A severe storm knocked down the tower and severely damaged the news studio and main facility of Sinclair-owned KTXS here on Sunday, June 8....

13/06/2025

Berklee's Music Business/Management Department Recognized by the Music Biz Association

Berklee's Music Business/Management Department Recognized by the Music Biz A...

13/06/2025

ATSC Honors Aldo Cugnini, Clarence Hau

WASHINGTON The ATSC, the Broadcast Standards Association, honored veteran technologist Aldo Cugnini and Clarence Hau, Senior Vice President of Standards, Policy...

13/06/2025

ESPN Doubles Down on Immersive Fan Experience for UFL Championship

(Editor's note: The 2025 UFL Championship Game between the D.C. Defenders and Michigan Panthers kicks off Saturday, June 14, at 8 p.m. Eastern. The game wil...

13/06/2025

Soulyft Audio release Chime

New iPad/iPhone synth App announced Following on from last year's release of Gradient Synth - which reached #6 on the App Store's Paid Music charts ...

13/06/2025

HBO Max Plans July Launches in 12 New Markets

LONDON Warner Bros. Discovery has announced that HBO Max will launch direct-to-consumer in multiple new countries this July as the streamer becomes available in...

13/06/2025

Verbit Launches Speaker Identification for Live ASR Broadcast Captions

AI voice transcription and captioning platform Verbit has added a new feature to its Captivate ASR solution the ability to identify specific features in automat...

13/06/2025

FCC's Anna Gomez Meets with TV Networks, Studio Execs and Unions

WASHINGTON Federal Communications Commission member Anna Gomez has wrapped up two weeks in California visiting broadcasters, television studio executives, enter...