Hi I am new to IOS developing. I've been searching for a while, just can not find a good example.
I like to create an app dynamically detect paper,
The app should be able to generate dynamic camera overlay by analysing current camera scenes.
like Adobe Scan.
I can program the sampling and detection algorithm myself,
but really not good on the IOS interface and technique.
I am using objective-C as programming language.
I like to know:
1, how to change the camera overlay in real time?
2, how should i put a ticker that repeatedly check camera scenes?
3, how can I access and modify a picture from iOS objective C?
Please give me some ideas or show me some examples.
Related
I am currently working on an iOS app that can take a picture programmatically using AVFoundation libraries like AVCaptureDevice through a custom button.
The new requirement is that the camera should automatically take a picture when the camera session detects something specific. For example, if the camera is open, and I line up an apple to fill a certain circle part of the capture screen, it should take the picture automatically. We can see this auto capture feature in some banking apps when you submit a mobile check deposit.
Does anyone know of existing libraries(open-source or proprietary) that can analyze images in real time while a user is taking a picture?
The first thing you are going to need to do is decide how you want to detect the apple. You can do this using shape detection, image recognition, or various other methods. This is important because you need to know the approach you want to take before you can identify the best way to implement it.
Once you know how you are going to identify the apple, the easiest way to do real-time image processing like this would be to use an existing augmented reality SDK. For example:
http://www.wikitude.com/products/wikitude-sdk/
http://artoolkit.org/
https://developer.vuforia.com/
If you are feeling really adventurous you could roll your own using AForge or a similar library. I have taken this approach in the past for basic shape detection projects.
Edit
The reason I suggest using an existing AR SDK is because generally they provide a lot of the glue between the camera feed and their API for you and it takes a lot of leg work out of the equation. Even though you won't be using any of the actual "augmentation" part of their SDKs, you can still take advantage of the detection part.
No matter what approach you take, you can think about it in the simplest terms of looking a picture, and figuring out if the item you want is in that picture. How do you decide? In most cases you look for a specific shape or pattern.
I am developing an augmented reality application where it recognizes objects and change the colors real time (example color of walls of a house). Can I use Vuforia SDK for this or are there any other better sdks to be used ?
Basically yes - Vuforia is able to detect pre-known images and let you know when something was detected, and what you do then is up to you. However, it depends on the objects you plan to recognize - Vuforia does not allow just any image to be detected, the image must have enough features. You can read about this here: https://developer.vuforia.com/library/articles/Solution/Natural-Features-and-Ratings
Is it possible to use Vuforia without a camera for image tracking?
Basically I would like a function I could call with an image as a indata parameter and coordinates of a image target as a result. Does that exist?
It is unfortunately not possible. I've been looking for such an option myself several times while working on a Moodstocks (image recognition SDK) / Vuforia mashup (see these 2 blog posts if you are interested in it), but the Vuforia SDK prevents the use of any other source than the camera.
I guess the main reason for this is that the camera management is fully handled internally by the Vuforia SDK, probably in order to make it easier to use as managing the camera by ourselves is at best a boring task (lines and lines of code to repeat in each project...), at worst a huge pain in the ass (especially on Android where there are sometimes devices than don't behave as expected).
By the way, it looks to me like the Vuforia SDK is not the best solution you can find for your use case: it is mainly an augmented-reality SDK, focussed on real-time tracking, which imply working with a camera stream... so using it to do "simple" image recognition looks really overkill!
I have a Unity/iOS app that captures the user's photo and displays it in the 3D environment. Now I'd like to leverage CIFaceFeature to find eye positions, which requires accessing the native (Objective-C) layer. My flow looks like:
Unity -> WebCamTexture (encode and send image to native -- this is SLOW)
Obj-C -> CIFaceFeature (find eye coords)
Unity -> Display eye positions
I've got a working prototype, but it's slow because I'm capturing the image in Unity (WebCamTexture) and then sending it to Obj-C to do the FaceFeature detection. It seems like there should be a way to simply ask my Obj-C class to "inspect the active camera". This would have to be much, much faster than encoding and passing an image.
So my question, in a nutshell:
Can I query in Obj-C 'is there a camera currently capturing?'
If so, how do I 'snapshot' the image from that currently running session?
Thanks!
You can access the Camera's preview capture stream by changing CameraCapture.mm in unity.
I suggest that you have a look at some existing plugin called Camera Capture for an example of how additional camera I/O functionality can be added to the capture session / "capture pipeline".
To set you off in the right direction. have a look at the function initCapture in CameraCapture.mm :
- (bool)initCapture:(AVCaptureDevice*)device width:(int)w height:(int)h fps:(float)fps
Here you will be able to add to the capture session.
And then you should have a look at the code sample provided by Apple on Facial Recognition :
https://developer.apple.com/library/ios/samplecode/SquareCam/Introduction/Intro.html
Cheers
Unity 3D allows execution of native code. In the scripting reference, look for native plugins. In this way you can display a native iOS view (with the camera view, possibly hidden depending on your requirements) and run Objective C code. Then return the results of eye detection to Unity if you need it in a 3D view.
I am a very beginner in Objective-C and iOS programming. I spent a month to find out how to show a 3D model using OpenGL ES (version 1.1) on top of the live camera preview by using AvFoundation. I am doing a kind of augmented reality application on iPad. I process the input frames and show 3D object overlay with the camera preview in realtime. These was fine because there are so many site and tutorial about these things (Thanks to this website as well).
Now, I want to make a screen capture of the whole screen (the model with camera preview as the background) as the image and show in the next screen. I found a really good demonstration here, http://cocoacoderblog.com/2011/03/30/screenshots-a-legal-way-to-get-screenshots/. He did everything I want to do. But, as I said before, I am so beginner and don't understand the whole project without explanation in details. So, I'm stuck for a while because I don't know how to implement this.
Does anybody know any of good tutorial or any kind of source in this topic or any suggestion that I should learn more in order to do this screen capture? This will help me a lot to moving on.
Thank you in advance.
I'm currently attempting to solve this same problem to allow a user to take a screenshot of an Augmented Reality app. (We use Qualcomm's AR SDK plugged into Unity 3D to make our AR apps, which saved me from ever having to learn how to programmatically render OpenGL models)
For my solution I am first looking at implementing the second answer found here: How to take a screenshot programmatically
Barring that I will have to re-engineer the "Combined Screenshots" method found in CocoaCoder's Screenshots app.
I'll check back in when I figure out which one works better.
Here are 3 very helpful links to capture screenshot:
OpenGL ES View Snapshot
How to capture video frames from the camera as images using AV Foundation
How do I take a screenshot of my app that contains both UIKit and Camera elements
Enjoy