Features · Camera scoring
Every dart, counted
Camera darts scoring in Sridu needs nothing more than one to four ordinary USB webcams around your board. The app finds the board on its own, sees every dart from several sides and has the score up before you throw the next one.
- One to four USB webcams, no special kit
- Set up with one button
- Asks when a dart sits on a wire
- No picture leaves your computer
- T2060 points
- 1close to the wire
- T2060 points
Check dart 20.6 mm from the wire · measured 3 times
Set up once
One button does the setup
To build the camera mounts yourself, see DIY auto scoring. For which webcams to buy, how many you need and where to mount them, see the hardware page. Once they are up, the rest takes about a minute.
- Open CamerasPlug the webcams in and open Cameras in the app. Allow camera access when the browser asks.
- Press Auto setupSridu picks the dart cameras and ignores the built-in webcam, virtual cameras and phone cameras. Each camera then finds the board and measures it.
- Check the picturesEach picture is straightened out as if you were looking at the board head-on, with the app’s lines drawn over it. Check that the 20 is at the top, the app’s numbers sit next to the real ones and the lines lie on the wires. Then tap Looks right.
- Lock the pictureWith your board light on, lock exposure, focus and white balance under Image. A webcam that keeps readjusting itself throws the detection off. The settings are saved for each camera.
20 in the wrong place? Cameras can hang at any angle, so Sridu reads the number ring and compares the cameras with each other to find the 20. If a camera still gets it wrong, tap 20 wrong, then the real 20. If the lines are slightly off, Lines wrong opens that camera full size. Drag five points onto the bull and four wire crossings (a magnifier and the arrow keys help), then tap Refine.
During the game
Throw, pull, throw again
The cameras watch the board all the time. They can tell a thrown dart from your hand, and they don’t mistake a tight group or a bounce-out for you pulling your darts. You only step in when something really is wrong.
- Darts are being pulledDetection readyTakeout
Pull your darts and the next visit starts by itself. One at a time is fine, and a tight group is not mistaken for a takeout.
- Tight groups
- T2060
- T2060
- T2060
Three darts in the same bed, the last one touching the others. Each is measured on its own, even when its tip hides behind another dart.
- Bounce-outs
- T2060
- 0fell out (T20)
- 0Bounce-out
Darts vanish from the board with no hand in the picture, so the next dart knocked them out. They don’t count, and the visit goes on.
- Pushed in by handdoes not countA hand at the board
A dart that shows up together with a hand was pushed in, not thrown, so it doesn’t score.
- 4 cameras readyCamera 4 connectedPlug and play
Plug a camera in while the app is running. It takes a free slot, its old one if possible, and measures the board on its own.
- Re-measureCameras measuredBumped a camera arm?
Re-measure is right there in the game. Pull your darts, tap it, and every camera measures the board again in a few seconds. The 20 stays where it was.
- The visit ends by itselfAfter three darts the Next button fills up over 15 seconds, then the game moves on. Pulling your darts skips the wait.
- Watch it measureTurn on Camera scan in the settings and, for every dart, the line each camera measured sweeps across the board, like the animation at the top of this page.
Close calls
When it’s close, it asks
A dart right on the wire can go either way, and Sridu tells you when that happens. Darts that are clearly in a field just count.
- It looks again. If a dart is close to a wire or hard to see, the cameras measure it a few more times. The dart isn’t moving, so any difference between the readings is camera noise. That shows how reliable the reading is.
- Only real doubt gets flagged. A dart is only marked when it may well be in the next field. Sridu works that out from the distance to the wire, how much the readings vary and how precisely your board was measured. Everything else counts straight away.
- Orange means check. The dart turns orange on the board and in its chip, you hear a warning tone, and the caller says “Please check dart 2”.
- One tap to fix it. Tap the chip, then the correct field. If you leave it, the measured score stands.
- You decide how strict. Under Check throws in the settings, choose Rarely, Normal or Thorough, or switch it off in the game menu, and every dart counts as measured. Which level suits your board
- T2060 points
- 1close to the wire
- ·Dart 3
- T2060 points
- 1being corrected
- ·Dart 3
You have the last word
Correct a dart, or play without cameras
The cameras save you typing in scores, and you can always overrule them.
- Change any dartTap its chip under the score, then the correct field on the board. Zoom in and Whole board help with the small fields, and Miss (0) scores it as a miss.
- UndoTakes back the last dart or the whole last visit and shows a note of what was undone.
- No cameras yetTap the board to enter your darts. With a mouse, the field under the pointer lights up and shows its name before you click. Outside the double ring it shows 0, which is how you enter a miss.
- Cameras and fingers togetherIf the cameras miss a dart, tap it in. Cameras and tapping work together in every game mode.
- From your phoneIf you allow it, a phone at the oche can add and correct darts too. See second screen.
- Camera darts onlyOn the leaderboard, a result gets a green camera mark when every dart came from the cameras, with nothing corrected or typed in, and the Camera only switch shows just those. A server can also count only those.
Test throw
See what your cameras see
Test throw is a mode on the camera page that doesn’t score anything. Throw a few darts and follow each step of the measurement, in millimetres.
- For each camera you see the difference image (what changed in the picture) and the axis it measured along the dart.
- On the board you see where the axes cross, how far apart they are, how many cameras were used and how confident the reading is.
- Close to a wire? You see how close, and whether the extra readings agreed.
- Pull the darts and it starts again. If you like to tinker, the detection sliders and a log are under Advanced.
Spread 0.5 mm · 3 cameras · axis intersection · certain
- 17
- T20
- 5 close to the wire (0.7 mm)
- D16
Accuracy
How accurate is it?
Put simply, each dart scores the field it is in, and the few that land right on a wire come to you for a check. Here are the numbers:
- 1500Points per camera, roughly, measured along every wire and colour edge of the board.
- ±0.5 mmHow closely the calibration matches the board on our test setup with real webcams. The camera check shows your own figure for each camera.
- <1 mmAverage error per dart with simulated cameras, where we know exactly where each dart landed. Real cameras add noise and shadows on top.
- 14Frames per second checked while it waits for the next dart. The dart itself is then measured at the camera’s full resolution.
- More cameras, fewer questionsWith one camera the app can only estimate where a hidden tip is, so it flags almost every dart. Two cameras are accurate as long as the darts don’t block each other. Three around the board work best. How many cameras?
- What throws it offA camera that got knocked, light that changes a lot, or a webcam that keeps adjusting its picture. Re-measure and lock the picture again, and the accuracy is back. More fixes in Better detection.
- A knocked cameraBetween visits, while the board is empty, each camera’s picture is compared with the one from the last measurement. If a camera has moved, or you had to correct several darts in a short time, the cameras are measured again before the next visit and a short note says why. The 20 stays where it was. To do it yourself instead, switch off Re-measure cameras automatically in the settings.
- A dart on the floorA dart that bounces out without hitting another dart leaves nothing for the cameras to see, and by the rules it scores nothing anyway. If you want it counted as a dart thrown, tap outside the double ring to enter a miss.
- Your own numbersThe camera check shows how well each camera fits the board, and a test throw shows how closely the cameras agree on a dart. Both are in millimetres, for your own board and lighting. The Statistics tab of your profile also shows how many camera darts were right in your recent matches.
Under the hood
How camera darts scoring works
Everything runs in your browser on your own computer, and no camera picture leaves it. The one exception is up to you. In an online match you can let your opponent see a small live picture of your board while you throw.
We developed it on real camera footage from a Winmau Blade 6 with a printed surround and three USB webcams mounted at random angles.
- Finding the boardIt starts with the bull, because nothing else looks like a red spot inside a green ring. From there, 360 rays go outwards. The first coloured band they cross is the treble ring, the second is the double ring. The surround, logos and the wall are ignored.
- Measuring every edgeSix circles and all 20 wires give about 1500 measuring points. The colours it looks for come from the picture itself, so exposure and white balance don’t matter. Perspective and lens distortion are fitted together, so wide-angle webcams work fine.
- Finding the 20For a camera hanging at an angle, “up” means nothing. So the number ring is unrolled into a strip and compared with a template and with the other cameras. The 20 is settled for all cameras at once, and after you confirm it, the numbers on your own board become the template.
- WatchingAbout 14 times a second, each camera compares a small picture of the board with the last still one. A new dart shows up as a small change that stays put.
- Measuring the dartOnce the picture is still again, that spot is read at full camera resolution. A weighted line fit then finds the dart’s axis in each picture.
- Crossing the axesEach axis is projected onto the board. Straight lines stay straight and the tip sits on the board surface, so the axes from all cameras cross exactly at the tip. That works at any dart angle, even when the tip itself is hidden. An axis that misses the others by more than 12 mm, from a shadow or a flight for example, is dropped.
- Looking twiceA close reading is repeated on the next few frames. The median of the readings gives the position, and how much they vary gives the real measuring error. Together with the precision of the calibration, that gives the chance of the next field, and only a dart above it is flagged.
- Hands and takeoutsA hand is big and slow, a dart is small and fast. That is how Sridu tells a takeout from a throw, a bounce-out from pulled darts and a thrown dart from one pushed in by hand. Hand detection is on by default, and you can switch it off under Advanced.
FAQ
Good to know
Which webcams do I need?
Ordinary USB webcams with 720p or better. For models, mounting and how many you need, see the hardware page.
Can I use my laptop or phone camera?
Auto setup skips them on purpose. A dart camera has to be mounted firmly beside the board and look at it from the side, which a laptop or phone camera can’t do.
Does it work with one camera?
Yes, but with limits. Without a second viewpoint the tip can only be estimated, so almost every dart gets flagged. The app tells you this and offers to switch the checks off. With two to four cameras it is reliable.
Are my camera pictures uploaded anywhere?
No. The pictures are processed in your browser and never leave your computer. The only exception is Show my board in an online match. Switch it on and your opponent sees a small picture from one camera while you throw. None of it is stored.
Which browser?
Browsers only allow camera access over https or on localhost. play.sridu.com runs on https, and for your own server the self-hosting guide explains the setup. Chrome and Edge also let Sridu lock exposure, focus and white balance.
What if the light changes during the evening?
Sridu adjusts to gradual changes on its own whenever nothing is happening at the board. After a big change, tap Re-measure in the game and lock the picture again if you had locked it.
What if someone knocks a camera?
Once the board is empty, Sridu compares the camera pictures with the last measurement and measures the cameras again if one has moved. The board goes dark for a few seconds while that happens, and the 20 stays where it was. You can switch this off in the settings and tap Re-measure in the game whenever you like.
Hang the cameras, press one button
Camera darts scoring needs a few webcams, even light and one press of Auto setup. After that you throw and the cameras keep score.