Access second back camera on iphone 7 - ios

I would like to capture images using the secondary back camera on the iphone 7. How do I force the back camera to use the second lens to take images? When I print out the available devices there was only 1 back camera.
Availible devices: Optional([<AVCaptureFigVideoDevice: 0x105e12f70 [Back Camera][com.apple.avfoundation.avcapturedevice.built-in_video:0]>, <AVCaptureFigVideoDevice: 0x105d281e0 [Front Camera][com.apple.avfoundation.avcapturedevice.built-in_video:1]>, <AVCaptureFigAudioDevice: 0x174097c00 [iPhone Microphone][com.apple.avfoundation.avcapturedevice.built-in_audio:0]>])
Picture to show what I'm talking about..

Related

Swift camera zoom to 0.5x in wide angle lens

I have zoom feature working(1x onwards) for custom camera implemented using AVFoundation. This is fine till the iPhone X models. But I wanted to have 0.5x zoom in iPhone 11.
Any help would be appreciable.
I'm not I understood the question correctly. I don't think you can achieve a 0.5x zoom only using the wide-angle camera.
If you refer to the 0.5x zoom as in the native iOS camera, you achieve that by switching from the wide-angle camera to the ultra wide-angle camera.
I think you have two options:
You can switch directly to the ultrawide camera via a button or so (below a short snippet for selecting the camera and assigning it to your active device.
if let device = AVCaptureDevice.default(.builtInUltraWideCamera, for: .video, position: .back) {
videoDevice = device
} else {
fatalError("no back camera")
}
On supported devices like the iphone11 you can use the .builtInDualCamera as your active device. In this case, the system will automatically switch between the different cameras depending on the zoomFactor. Of course, on iPhone 11pro and 12pro series, you can even use .buildInTripleCamera to go to 2x zoom. You can even check for when the switch happens, please refer to the link below for more information.
https://developer.apple.com/documentation/avfoundation/avcapturedevice/3153003-virtualdeviceswitchovervideozoom

AR.js distorted perspective: How to use a personalized camera calibration file `camera_para.dat` so that the "floor" plane is horizontal?

I'm looking into AR.js for an augmented reality use case where 3D objects do not appear directly on the hiro marker, but somewhere around the marker.
When I view my AR scene through my iPhone 7 from the top, everything looks fine, but when I tilt my camera to get more perspective, AR.js doesn't apply the same perspective to the AR world so that distant virtual objects appear as if they were located on an inclined plane.
I created an example page to illustrate this behaviour: When viewed from above, the grids match perfectly, but when viewed from the side, the planes mismatch.
Are there any settings I can apply to configure AR.js (or ARToolKit, which it depends on)? Maybe there's a way to define the field of view of my webcam there?
[EDIT] One week later, I would reword my question to: How can I use a device-specific camera_para.dat ARToolkit camera calibration file in AR.js without generating side effects such as a distorted rendering?
Updating the intrinsic optical characteristics of the camera, also known as calibration, might help!
The artoolkitx-calibration app is made for calibrating cameras. Unfortunately, the app is not available on the App Store currently. You can, however, deploy it to your development device using Xcode.
Alternatively, the ARToolKitX calibration server might contain camera calibration results for your smartphone - Unfortunately, it returns 204 (no content) for the iPhone 7 (a.k.a. apple/iPhone/iPhone9,3, camera 0, aspect ratio 16:9).
By the way,
camera_para.dat for several older iOS devices can be found on GitHub:
iPad 2: 0,7 MP
iPad Air 2: 8 MP, f/2.4
iPad Mini 3: 5 MP, f/2.4
iPhone 4: 5 MP, f/2.8
iPhone 4s: 8 MP, f/2.4
iPhone 5: 8 MP, f/2.4
iPhone 5s: 8 MP, f/2.2 (similar to iPhone 6, iPhone 6 Plus)
iPhone 6s Plus: 12 MP, f/2.2 (similar to iPhone SE, iPhone 6s)
Unfortunately, newer iPhone cameras have different specs (e.g. iPhone 7 or iPhone 8: 12 MP, f/1.8) so I doubt that any of these camera calibration settings would fit perfectly for them...

How can I have a camera on a defined part of the screen on iPhone 4/4S?

I am using the AVFoundation framework to have a camera view on my iPhone app.
On iPhone 5 and further, the camera fills the entire view where it's in. On iPhone 4/4S, the view isn't filled entirely and I get blank spaces on both sides of the view. I believe it's not because of the constraints, but because of the proportion of the iPhone's screen :
With the preset AVCaptureSessionPresetPhoto, on iPhone 5/6, the ratio of the image is 3/4. On iPhone 4/4S with the same preset, the ratio of the image is 9/16. It looks like the shape of my camera's view can be filled with a 3/4 image, not a 9/16 image.
So I looked for all the preset available, and I tried the preset AVCaptureSessionPreset640x480 thinking that the problem would be solved since 640*480 delivers a 3/4 image... But it didn't fixed anything, I still have blank spaces on both sides of the view.
Is there a way to adapt the resolution with the AVFoundation framework ?
(I think my problem would be easier to understand with images, but I'm not authorized to post some yet)
I didn't found a way to use the camera on the exact ratio i wanted, so I just created a new ViewController that I only use on the iPhone 4/4S, with a different interface for this device

Flash CameraUI orientation is wrong

We're developing an AIR app for android and iOS. An important part of the app is taking photos. Using flash.media.CameraUI works perfectly on android, but we experience problems on iOS.
In the iOS camera application, when we rotate the iPad, the orientation is wrong: If we rotate the pad clockwise, the image is rotated anticlockwise. The UI buttons have the correct orientation though, and when the photo is taken, the resulting bitmap has the right orentation based on the orientation of the camera, not the actual view on the screen.
Looking at different camera apps, I notice that when the pad is rotated so the orientation changes clockwise, the camera does three things: First, the displayed image immediately becomes rotated 90 degrees anti-clockwise (so it looks wrong). Then, the image slowly rotates 90 degrees clockwise, to restore the correct orientation. In addition, the UI buttons change orientation so the text is displayed correctly.
It seems as in our app, it only rotates the image slowly without doing the first immediate rotation. Thus, the end result is wrong.
Anyone know how to fix this?
After some more research, I found that the issue isn't just restricted to AIR.
UIImagePickerController camera view rotating strangely on iOS 8 (pictures)

iOS FullScreen AVCaptureSession

I am developing a realtime video processing app for iOS 5. The video stream dimensions need to match the screen size of the device. I currently only have a iPhone 4 to develop against. For the iPhone 4 I set the AVCaptureSession preset to AVCaptureSessionPresetMedium:
AVCaptureSession *session = [AVCaptureSession new];
[session setSessionPreset:AVCaptureSessionPresetMedium];
The captured images (via CMSampleBufferRef) have the size of the screen.
My question: Is the assumption correct that the images captured with a session preset of AVCaptureSessionPresetMedium have the full screen device dimensions on iPhone 4s and iPad2 as well? I unfortunately cannot verify that myself.
I looked at the apple documentation:
http://developer.apple.com/library/mac/#documentation/AVFoundation/Reference/AVCaptureSession_Class/Reference/Reference.html#//apple_ref/doc/constant_group/Video_Input_Presets
but I cannot find a ipad2 dimension preset of 1024/768 and would like to save me the performance penalty of resizing images in real time.
Whats the recommended path to go?
The resolution of the camera and the resolution of the screen aren't really related anymore. You say
The captured images (via CMSampleBufferRef) have the size of the
screen
but I don't think this is actually true (and it may vary by device). A medium capture on an iPad 2 and an iPhone 4s is 480x360. Note this isn't even the same aspect ratio as the screen on a phone or iPod: the camera is 4x3 but the screen is 3x2.

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