I'm doing research that requires a camera that is automated, but it also has to coordinate with the rotation of a filter wheel and take a series of images relatively quickly (4 images in less than 2 seconds). I'd like to do this by writing a Matlab script to control everything and handle incoming data.
I know there are scientific cameras out there that can do this job and have very good SDKs, but they are also very expensive if they have the sensor size that I need (APS-C or larger). Using a simple Sony mirrorless camera would work perfectly for my needs as long as I can control it.
I'd like to use Matlab or LabView to automate the data acquisition, but I'm not sure what is possible with this API Beta SDK. My understanding is that it is designed to allow the user to create a stand-alone app, but not to integrate camera commands into a programming environment like Matlab. I know there are ways to call an external application from within Matlab, but I've also read one person's account of trying this indirect method and it sounds like it takes a long time to trigger the camera this way (five seconds or more for a single image). That would be too slow.
Does the SDK allow camera control directly from a program like Matlab?
My understanding is that it is designed to allow the user to create a stand-alone app, but not to integrate camera commands into a programming environment like Matlab.
Don't trust marketing statements, that's just how they advertise their SDK. If you take a closer look into the documentation, you will realize your Camera runs a server which accepts JSON-RPC over HTTP commands. I would use an already exiting examples for Android (Java) and adapt it to run on your operating system, you can directly call java code from your matlab console.
I've had great success communicating between MatLab and a Sony QX1 (the 'webwrite' function is your friend!).
That said, you will definitely struggle to implement anything like precise triggering. The call-response times vary greatly (~5 seconds +-2 ish).
You might be able to get away with shooting video and then pulling the relevant frames out of the sequence?
Related
I want to make an attendance system where users can attend with the camera.
I am using
tflite_flutter.
google_ml_kit
It works perfectly but if I take a picture and show it in front of the camera it also works. I need to stop that. How can I detect pictures or videos or real faces in flutter?
In order to detect if faces are real or not, it may not be very hard to use a normal camera as the input for the system, as it may not provides enough data to prevent picture or video to be used to trick the system, That's why many face recoqnition systems uses some kind of extra sensors to ensure the security of the system.
For your case of attendance system, it may be better to get another external device/sensor that is able to feed the required data to prevent fake data to the system maybe via something like BLE.
What is the best way, if any, to use Apple's new ARKit with multiple users/devices?
It seems that each devices gets its own scene understanding individually. My best guess so far is to use raw features points positions and try to match them across devices to glue together the different points of views since ARKit doesn't offer any absolute referential reference.
===Edit1, Things I've tried===
1) Feature points
I've played around and with the exposed raw features points and I'm now convinced that in their current state they are a dead end:
they are not raw feature points, they only expose positions but none of the attributes typically found in tracked feature points
their instantiation doesn't carry over from frame to frame, nor are the positions exactly the same
it often happens that reported feature points change by a lot when the camera input is almost not changing, with either a lot appearing or disappearing.
So overall I think it's unreasonable to try to use them in some meaningful way, not being able to make any kind of good point matching within one device, let alone several.
Alternative would to implement my own feature point detection and matching, but that'd be more replacing ARKit than leveraging it.
2) QR code
As #Rickster suggested, I've also tried identifying an easily identifiable object like a QR code and getting the relative referential change from that fixed point (see this question) It's a bit difficult and implied me using some openCV to estimate camera pose. But more importantly very limiting
As some newer answers have added, multiuser AR is a headline feature of ARKit 2 (aka ARKit on iOS 12). The WWDC18 talk on ARKit 2 has a nice overview, and Apple has two developer sample code projects to help you get started: a basic example that just gets 2+ devices into a shared experience, and SwiftShot, a real multiplayer game built for AR.
The major points:
ARWorldMap wraps up everything ARKit knows about the local environment into a serializable object, so you can save it for later or send it to another device. In the latter case, "relocalizing" to a world map saved by another device in the same local environment gives both devices the same frame of reference (world coordinate system).
Use the networking technology of your choice to send the ARWorldMap between devices: AirDrop, cloud shares, carrier pigeon, etc all work, but Apple's Multipeer Connectivity framework is one good, easy, and secure option, so it's what Apple uses in their example projects.
All of this gives you only the basis for creating a shared experience — multiple copies on your app on multiple devices all using a world coordinate system that lines up with the same real-world environment. That's all you need to get multiple users experiencing the same static AR content, but if you want them to interact in AR, you'll need to use your favorite networking technology some more.
Apple's basic multiuser AR demo shows encoding an ARAnchor
and sending it to peers, so that one user can tap to place a 3D
model in the world and all others can see it. The SwiftShot game example builds a whole networking protocol so that all users get the same gameplay actions (like firing slingshots at each other) and synchronized physics results (like blocks falling down after being struck). Both use Multipeer Connectivity.
(BTW, the second and third points above are where you get the "2 to 6" figure from #andy's answer — there's no limit on the ARKit side, because ARKit has no idea how many people may have received the world map you saved. However, Multipeer Connectivity has an 8 peer limit. And whatever game / app / experience you build on top of this may have latency / performance scaling issues as you add more peers, but that depends on your technology and design.)
Original answer below for historical interest...
This seems to be an area of active research in the iOS developer community — I met several teams trying to figure it out at WWDC last week, and nobody had even begun to crack it yet. So I'm not sure there's a "best way" yet, if even a feasible way at all.
Feature points are positioned relative to the session, and aren't individually identified, so I'd imagine correlating them between multiple users would be tricky.
The session alignment mode gravityAndHeading might prove helpful: that fixes all the directions to a (presumed/estimated to be) absolute reference frame, but positions are still relative to where the device was when the session started. If you could find a way to relate that position to something absolute — a lat/long, or an iBeacon maybe — and do so reliably, with enough precision... Well, then you'd not only have a reference frame that could be shared by multiple users, you'd also have the main ingredients for location based AR. (You know, like a floating virtual arrow that says turn right there to get to Gate A113 at the airport, or whatever.)
Another avenue I've heard discussed is image analysis. If you could place some real markers — easily machine recognizable things like QR codes — in view of multiple users, you could maybe use some form of object recognition or tracking (a ML model, perhaps?) to precisely identify the markers' positions and orientations relative to each user, and work back from there to calculate a shared frame of reference. Dunno how feasible that might be. (But if you go that route, or similar, note that ARKit exposes a pixel buffer for each captured camera frame.)
Good luck!
Now, after releasing ARKit 2.0 at WWDC 2018, it's possible to make games for 2....6 users.
For this, you need to use ARWorldMap class. By saving world maps and using them to start new sessions, your iOS application can now add new Augmented Reality capabilities: multiuser and persistent AR experiences.
AR Multiuser experiences. Now you may create a shared frame of a reference by sending archived ARWorldMap objects to a nearby iPhone or iPad. With several devices simultaneously tracking the same world map, you may build an experience where all users (up to 6) can share and see the same virtual 3D content (use Pixar's USDZ file format for 3D in Xcode 10+ and iOS 12+).
session.getCurrentWorldMap { worldMap, error in
guard let worldMap = worldMap else {
showAlert(error)
return
}
}
let configuration = ARWorldTrackingConfiguration()
configuration.initialWorldMap = worldMap
session.run(configuration)
AR Persistent experiences. If you save a world map and then your iOS application becomes inactive, you can easily restore it in the next launch of app and in the same physical environment. You can use ARAnchors from the resumed world map to place the same virtual 3D content (in USDZ or DAE format) at the same positions from the previous saved session.
Not bulletproof answers more like workarounds but maybe you'll find these helpful.
All assume the players are in the same place.
DIY ARKit sets up it's world coordinate system quickly after the AR session has been started. So if you can have all players, one after another, put and align their devices to the same physical location and let them start the session there, there you go. Imagine the inside edges of an L square ruler fixed to whatever available. Or any flat surface with a hole: hold phone agains surface looking through the hole with camera, (re)init session.
Medium Save the player aligning phone manually, instead detect a real world marker with image analysis just like #Rickster described.
Involved Train an Core ML model to recognize iPhones and iPads and their camera location. Like it's done with human face and eyes. Aggregate data on a server, then turn off ML to save power. Note: make sure your model is cover-proof. :)
I'm in the process of updating my game controller framework (https://github.com/robreuss/VirtualGameController) to support a shared controller capability, so all devices would receive input from the control elements on the screens of all devices. The purpose of this enhancement is to support ARKit-based multiplayer functionality. I'm assuming developers will use the first approach mentioned by diviaki, where the general positioning of the virtual space is defined by starting the session on each device from a common point in physical space, a shared reference, and specifically I have in mind being on opposite sides of a table. All the devices would launch the game at the same time and utilize a common coordinate space relative to physical size, and using the inputs from all the controllers, the game would remain theoretically in sync on all devices. Still testing. The obvious potential problem is latency or disruption in the network and the sync falls apart, and it would be difficult to recover except by restarting the game. The approach and framework may work for some types of games fairly well - for example, straightforward arcade-style games, but certainly not for many others - for example, any game with significant randomness that cannot be coordinated across devices.
This is a hugely difficult problem - the most prominent startup that is working on it is 6D.ai.
"Multiplayer AR" is the same problem as persistent SLAM, where you need to position yourself in a map that you may not have built yourself. It is the problem that most self driving car companies are actively working on.
I am trying to accomplish this task:
Running an app on a Samsung Smart TV (in background, kind of)
This app should check the screen content in an interval and calculate the main color of screen content or the main colors of each border (lets say 20% of width and heigth from border)
Use the remote accessible api for HUE to control n Philips HUE Lights to accomplish a roomwide ambilight.
Now as I am an android developer and do not have any experience with Smart-TVs I would ask you, if this could be accomplished (or if there is any show stopper) and you have some tips for me, prior to diggin into this very deeply? The actual "How to get startet developing a SmartTV App" will not be the main problem and I am into this right now.
So my actual questions are:
What is the best bettern (or is it impossible) to have something like an background job in an Samsung SmartTV? Maybe something like a ticker app with no actual visible overlay or a very small one, would also be a solution?
Is there a way to access the currently shown picture on TV, so I get access to the rgb values of the areas/pixels or maybe a screenshot or thumbnail of the screen, no matter what the source of the signal is, as I have to analyze it to get the color.
Would be great I you could advise me some resources specially to this tasks and give me some advice if this will be working or if there are any limitations or better concepts.
It seems the Huey app in the Play Store does what you want but accomplishes it in a different manner, using the camera of a device set in front of the TV to determine the colors.
Steve,
Hue API is not fit to be used as Ambilight control facility, since Hue API is not run real-time.
Overheads generated by client and server make it possible to develop Hue API - based Ambilight apps supporting 1-2-3 Hue Lights,
since hue, sat, bri are updated by server-side run scripts, so upddate is slow.
You need to run Ambilight real-time ( 5-10 updates in 1 sec) and have 8-10 or more Hue lights controlled real-time.
So I develop real-time hardware based Ambilight demo for my students.
Hue API alone is not heavy but Hue API calls are server-side processed by API handlers, to send calls via Zigbee master to Hue Lights with Zigbee
hardware and protocol embedded.
Smart TV is hardware based solution, so runs almost real-time and you can get video image updated frequently.
This may pique your interests: Build your own Ambilight clone with the Raspberry Pi
I am researching how to create an app for my work that allows clients to download the app (preferably via the app store) and using some sort of wifi triangulation/fingerprints be able to determine their location for essentially an interactive tour.
Now, my question specifically is what is the best route to take for the iPhone? None of the clients will be expected to have jail broken iPhones.
To my understanding this requires the use of the wifi data which is a private api therefore not meeting the app store requirements. The biggest question I have is how does American Museum of Natural History get away with using the same technology, but still available on the app store?
if you're unfamiliar with American Museum of Natural History interactive tour app, see here:
http://itunes.apple.com/us/app/amnh-explorer/id381227123?mt=8
Thank you for any clarification you can provide.
I'm one of the developers of the AMNH Explorer app you're referencing.
Explorer uses the Cisco "Mobility Services Engine" (MSE) behind the scenes to determine its location. This is part of their Cisco wifi installation. The network itself listens for devices in the museum and estimates their position via Wifi triangulation. We do a bit of work in the app to "ask" the MSE for our current location.
Doing this work on the network side was (and still is) the only available option for iOS since, as you've found, the wifi scanning functions are considered to be private APIs.
If you'd like to build your own system and mobile app for doing something similar, you might start with the MSE.
Alternatively, we've built the same tech from Explorer into a new platform called Meridian which provides location-based services on both iOS and Android. Definitely get in touch with us via the website if you're interested in building on that.
Update 6/1/2017
Thought I would update this old answer - AMNH is no longer using the Wifi-based system I describe above, as of a few years ago. They now use an installation of a few hundred battery-powered Bluetooth Beacons (also provided by Meridian). The device (iOS or Android) scans for nearby beacons and, based on their known locations and RSSI values, triangulates a position. You can read more about it in this article.
Navizon offers an indoor positioning solution that works for iOS as well as any other platform. You can check it out here:
http://www.navizon.com/product-navizon-indoor-triangulation-system
It works by triangulating the WiFi signals transmitted by the device. Since it doesn't require an app to run on the phone, it bypasses the iOS limitations and can locate any other WiFi device for that matter.
Google recently launched an API called Maps Geolocation API. You can use it for indoor tracking of devices, which essentially can be used to achieve something similar to what AMNH's app does.
I would do this using Augmented Reality. There is a system sort of in place for this, the idea being that you place physical markers that have virtual information associated with them. I believe the system I saw was a type of bar code. When a user holds up the phone with the app, the app uses the camera to read the code and then display information. This could easily be used to make a virtual tour type app distributable through the app store and not even require a WIFI or 3/4G connection. This assumes that you simply load your information and store it locally with your app. Then to update it you simply push an update through the app store. Another solution is to use a SOAP/REST service and provide the information in that way, and this does not use private API's, though it does require some form of internet connection. For this you can see a question I asked about this topic a little bit ago:
SOAP/XML Tutorials Question
In addition, you could load a map of your tour location, and based on what code is scanned you can locate the user on the map and give suggested routes based on interests etc.
I found this tutorial recently on augmented reality, I haven't gone through it, but if its anything like the rest of Ray's tutorials, it will be extremely helpful.
http://www.raywenderlich.com/3997/introduction-to-augmented-reality-on-the-iphone
I'll stick around to clarify any questions or other concerns you may have with your app.
To augment the original answer for devs who were using Cisco MSE for indoor location - now they have an iOS and Android SDK which enables you to do indoor location using the MSE. A simulator can be used as well to develop the app without implementing the infrastructure to start with : https://developer.cisco.com/site/cmx-mobility-services/downloads/
For indoor location you can use Bluetooth LE beacons since it's a very accessible technology nowadays, there are several methods:
Trilateration: it uses 3 beacons, but with the noise and attenuation of Bluetooth signals, it gets quite difficult to determine the exact position and also it's not easy to use more than 3 beacons to increase accuracy.
Levenberg Marquadt method: used to solve non-linear squares problems showed good results on indoor positioning.
Dead Reckoning method: using the motion co-processor of the device, giving an initial position you can calculate the moving path of the device. Not that easy to implement anyway.
I wrote a post on the topic, you can find more info here: http://bits.citrusbyte.com/indoor-positioning-with-beacons/
And you can use this iOS app for your own indoor positioning experiments: https://github.com/citrusbyte/beacons-positioning
I doubt the American Museum is actually using private APIS; you'll probably find the routers that have been setup serve different responses to each other, so the app can detect it's position in the museum.
If you are looking for a cheaper to way to do the same task, you could have signs with QR codes, and use an open source library to let users scan these barcodes as they move through the museum, and update the onscreen content accordingly. On an even more low tech level, you can just tag each area with unique numbers, and distinguish that way.
What is the biggest limitation of making/using webapps?
I'm thinking that when you use localstorage, offline-browsing and geo-abilities thaht you get from html5 the differences are quite small (except for games).
The great benefit from using webapps is that they are cross-platfrom compatible!
One of the biggest limitation is access to hardware. You can't access USB ports, specialized hardware you might have (printers, bardcode readers), and other stuff, and of course, you don't have access to some very important APIs that you need today to run games (DirectX, OpenGL).
But I agree: every day they are fewer reasons to not go with a WebApp instead of a Native APP.
For iOS: When using geolocation for webapp, the user will get prompt about giving location access every time, which could be annoying for the user. Native app, only the first time.
The UI performance is also not as smooth as native. Scrolling in webview has a "slower" acceleration compared to native view scrolling.
Performance is one major difference. I see from around 20X to over 200X speed improvements when converting from Javascript to compiled C/Objective C code. One can also do real-time audio and video processing in native code, as well as low-level networking, etc.
One interesting limitation (HTML5-wise) I see is from a point of intellectual property. Since a lot of code (raw JavaScript + HTML) is exposed to the user, you have to carefully decide which components will be "open" to end users. Not aware of any standard way to lock or hide your IP once it leaves your server.
Webapps are great for reaching multiple hardware devices, you can update your app a lot faster, thus feedback is quicker. However, your users will require an always-on internet connection to use your webapp, that's probably the biggest negative about them in comparison to a native (offline) app.