How Does the Magic Yellow First-Down Line Work?

Sportvision
Sportvision

If you attend a Super Bowl party on Sunday, you’ll probably hear at least one casual football viewer ask, “How do they get that yellow first-down line on the field?” While “magic” is a fine answer in its own right, the real explanation is a bit more technologically intense. Let’s have a look at the background and mechanics behind every football fan’s shining beacon: the yellow first-down line.

According to Allen St. John’s 2009 book The Billion Dollar Game: Behind the Scenes of the Greatest Day in American Sport - Super Bowl Sunday, the first-down line actually emerged from the ashes of one of sports broadcasting’s bigger debacles: the FoxTrax system for hockey, which was designed by a company called Sportvision. FoxTrax—which hockey fans no doubt remember as the much-maligned “technopuck” that debuted in 1996—employed a system of cameras and sensors around a hockey rink to place a little blue halo around the puck.

FoxTrax wasn't a great fit for NHL broadcasts: Hockey purists hated the intrusion into their game, and casual fans didn’t flock to hockey just because the puck was suddenly easier to follow. However, the system inspired producers to think of new ways to insert computerized images into live sports broadcasts.

The idea of using a line to mark the first down in football was a natural extension, and Sportvision debuted its 1st and Ten system during ESPN’s broadcast of a Bengals-Ravens tilt on September 27, 1998. A couple of months later, rival company Princeton Video Image unveiled its Yellow Down Line system during a Steelers-Lions broadcast on CBS. (Sportvision is still kicking, and ESPN acquired all of PVI’s intellectual property in December 2010.)

BUT HOW DOES IT WORK?

It takes lots of computers, sensors, and smart technicians to make this little yellow line happen. Long before the game begins, technicians make a digital 3D model of the field, including all of the yard lines. While a football field may look flat to the naked eye, it’s actually subtly curved with a crown in the middle to help rainwater flow away. Each field has its own unique contours, so before the season begins, broadcasters need to get a 3D model of each stadium’s field.

These models of the field help sidestep the rest of the technological challenges inherent to putting a line on the field. On game day, each camera used in the broadcast contains sensors that record its location, tilt, pan, and zoom and transmit this data to the network’s graphics truck in the stadium’s parking lot. These readings allow the computers in the truck to process exactly where each camera is within the 3D model and the perspective of each camera. (According to How Stuff Works, the computers recalculate the perspective 30 times per second as the camera moves.)

After they get their hands on all of this information, the folks in the graphics truck know where to put the first-down line, but that’s only part of the task. When you watch a football game on television, you’ll notice that the first-down line appears to actually be painted on the field; if a player or official crosses the line, he doesn’t turn yellow. Instead, it looks like the player’s cleat is positioned on top of an actual painted line. This effect is fairly straightforward, but it’s difficult to achieve.

To integrate the line onto the field of play, the technicians and their computers put together two separate color palettes before each game. One palette contains the colors—usually greens and browns—that naturally occur on the field’s turf. These colors will automatically be converted into yellow when the line is drawn on to the field.

All of the other colors that could show up on the field—things like uniforms, shoes, footballs, and penalty flags—go into a separate palette. Colors that appear on this second palette are never converted into yellow when the first-down line is drawn. Thus, if a player’s foot is situated “on” the line, everything around his cleat will turn yellow, but the cleat itself will remain black. According to How Stuff Works, this drawing/colorizing process refreshes 60 times per second.

All this technology—and the people needed to run it—wasn’t cheap at first. It could cost broadcasters anywhere from $25,000 to $30,000 per game to put the yellow line on the field. Sportvision had to deploy a truck and a four-man crew with five racks of equipment. The cost has come down since then, and the process is now less labor-intensive. One technician using one or two computers can run the system, according to Sportvision, and some games can even be done without anyone actually at the venue.

Now you can explain it to everyone at your Super Bowl party during one of the less-exciting $5 million commercials.

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This post originally appeared in 2011.

10 LEGO Sets For Every Type of LEGO Builder 

Amazon
Amazon

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If you’re looking for a timeless gift to give this holiday season, look no further than a LEGO set. With kits that cater to a wide age range—from toddlers fine-tuning their motor skills to adults looking for a more engaged way to relax—there’s a LEGO set out there for everyone. We’ve rounded up some of our favorite sets on Amazon to help you find the LEGO box that will make your loved one smile this year. If you end up getting one for yourself too, don’t worry: we won’t tell.

1. Classic Large Creative Gift Box; $44

Amazon

You can never go wrong with a classic. This 790-piece box contains dozens of types of colored bricks so builders of any age can let their inner architect shine. With toy windows, doors, tires, and tire rims included in addition to traditional bricks, the building possibilities are truly endless. The bricks are compatible with all LEGO construction sets, so builders have the option of creating their own world or building a new addition onto an existing set.

Buy it: Amazon

2. Harry Potter Hogwarts Express; $64

Amazon

Experience the magic of Hogwarts with this buildable Hogwarts Express box. The Prisoner Of Azkaban-inspired kit not only features Hogwarts's signature mode of transportation, but also Platform 9 ¾, a railway bridge, and some of your favorite Harry Potter characters. Once the train is built, the sides and roof can be removed for play within the cars. There is a Dementor on board … but after a few spells cast by Harry and Lupin, the only ride he’ll take is a trip to the naughty list.

Buy it: Amazon

3. Star Wars Battle of Hoth; $160

Amazon

Star Wars fans can go into battle—and rewrite the course of history—by recreating a terrifying AT-AT Walker from the Battle of Hoth. Complete with 1267 pieces to make this a fun challenge for ages 10 and up, the Walker has elements like spring-loaded shooters, a cockpit, and foldout panels to reveal its deadly inner workings. But never fear: Even though the situation might look dire, Luke Skywalker and his thermal detonator are ready to save the day.

Buy it: Amazon

4. Super Mario Adventures Starter Course; $60

Amazon

Kids can play Super Mario in 3D with LEGO’s interactive set. After constructing one of the courses, young designers can turn on the electronic Mario figurine to get started. Mario’s built-in color sensors and LCD screens allow him to express more than 100 different reactions as he travels through the course. He’ll encounter obstacles, collect coins, and avoid Goomba and Bowser to the sound of the Mario soundtrack (played via an included speaker). This is a great gift for encouraging problem-solving and creativity in addition to gaming smarts.

Buy it: Amazon

5. Gingerbread House; $212

Amazon

Gingerbread houses are a great way to enjoy the holidays … but this expert-level kit takes cookie construction to a whole new level. The outside of the LEGO house rotates around to show the interior of a sweet gingerbread family’s home. Although the living room is the standout with its brick light fireplace, the house also has a kitchen, bedroom, bathroom, and outdoor furniture. A LEGO Christmas tree and presents can be laid out as the holidays draw closer, making this a seasonal treat you can enjoy with your family every year.

Buy it: Amazon

6. Elsa and Olaf’s Tea Party; $18

Amazon

LEGO isn’t just for big kids. Toddlers and preschoolers can start their LEGO journey early by constructing an adorable tea party with their favorite Frozen characters. As they set up Elsa and Olaf’s ice seats, house, and tea fixings, they’ll work on fine-motor, visual-spatial, and emotional skills. Building the set from scratch will enable them to put their own creative spin on a favorite movie, and will prepare them for building more complicated sets as they get older.

Buy it: Amazon

7. Collectible Art Set Building Kits; $120

Amazon

Why buy art when you can build it yourself? LEGO’s Beatles and Warhol Marilyn Monroe sets contain four options for LEGO art that can be built and displayed inside your home. Each kit comes with a downloadable soundtrack you can listen to while you build, turning your art experience into a relaxing one. Once you’re finished building your creation it can be exhibited within a LEGO brick frame, with the option to hang it or dismantle it to start on a new piece. If the 1960s aren’t your thing, check out these Sith and Iron Man options.

Buy it: Amazon

8. NASA Apollo Saturn V; $120

Amazon

The sky (or just the contents of your LEGO box) is the limit with LEGO’s Saturn V expert-level kit. Designed for ages 14 and up, this to-scale rocket includes three removable rocket stages, along with a command and service module, Lunar Lander, and more. Once the rocket is complete, two small astronaut figurines can plant a tiny American flag to mark a successful launch. The rocket comes with three stands so it can be displayed after completion, as well as a booklet for learning more about the Apollo moon missions.

Buy it: Amazon

9. The White House; $100

Amazon

Reconstruct the First Family’s home (and one of America’s most famous landmarks) by erecting this display model of the White House. The model, which can be split into three distinct sections, features the Executive Residence, the West Wing, and the East Wing of the complex. Plant lovers can keep an eye out for the colorful rose garden and Jacqueline Kennedy Garden, which flank the Executive Residence. If you’re unable to visit the White House anytime soon, this model is the next best thing.

Buy it: Amazon

10. Volkswagen Camper Van; $120

Amazon

Road trip lovers and camping fanatics alike will love this vintage-inspired camper. Based on the iconic 1962 VW vehicle, LEGO’s camper gets every detail right, from the trademark safari windshield on the outside to the foldable furniture inside. Small details, like a “Make LEGO Models, Not War” LEGO T-shirt and a detailed engine add an authentic touch to the piece. Whether you’re into old car mechanics or simply want to take a trip back in time, this LEGO car will take you on a journey you won’t soon forget.

Buy it: Amazon

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Why Do Cats Throw Up So Often?

Pixabay, Pexels
Pixabay, Pexels

Nearly every cat owner is used to regularly finding something their kitty coughed up hidden around their home. Vomiting in cats can happen so often that it's easy to grow desensitized to the behavior, but veterinarians say that the sight of your cat throwing up should never be ignored. Though it's usually benign, vomiting may indicate a health problem that needs to be taken care of.

To gauge whether your cat's puke is a sign of something serious, look for certain clues. According to The Spruce Pets, eating too fast is one of the most common causes of vomiting in cats, and it's usually harmless. If your cat hacks up undigested food immediately following meal times, that's likely the culprit. This behavior can be prevented by feeding your pet smaller portions, or adding an obstruction like a medium-sized ball to their bowl that they have to eat around. If the problem still persists, there may be something else causing it.

Hairballs are another potential source of your cat's retching. They may be just a gross annoyance to you, but to your cat, they can pose a serious health risk. Cats cough up the fur they can't digest, and if they don't, it could create a dangerous obstruction in their bowels. One way to help your hairball-prone cat is to brush them regularly. That way, there will be less fur for them to lick up.

These are the less concerning reasons for a cat to throw up. Vomiting can also be a symptom of health problems like feline inflammatory bowel disease, feline diabetes, hyperthyroidism, and chronic kidney disease. It's also possible that your cat ingested something harmful.

If there's no obvious explanation for your cat's vomiting, it's a good idea to reach out to your vet. While throwing up one to three times a month is considered normal, a cat that throws up multiple times in a short period may need medical attention. When analyzing your pet's behavior, look for other symptoms as well: Cats that exhibit symptoms like diarrhea or loss of appetite in addition to throwing up should always be taken to the vet.

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