I'm trying to use zxing to detect small barcodes on playing cards for the purpose of scanning all hands after a game of bridge for easy analysis of the game.
I have looked at the GenericMultipleBarcodeReader class which seems to do exactly what I want. However, there already seems to be a problem in recognizing even one barcode. I believe that they are too small for easy recognition: even calling the detect method on an instance of MonochromeRectangleDetector class results in a NotFoundException.
I have attached an example image to give an idea of what the cards look like. Does anyone have suggestions on how to approach this problem, or are the barcodes just too small for zxing to recognize them? The official zxing Android app also does not detect any barcode if I use it on the playing card.
Thanks!
http://i.stack.imgur.com/ol33q.jpg
I don't recognize that as any known barcode format. Are you sure it is not just some marking, or some custom format? certainly this is why it is not read.
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I'm building an iOS app which requires me to allow the users to record a 15sec clip (with UIImagePickerController for example) and then convert it into an animated GIF. How could I achieve this? Is there any library/framework available for such task?
Thanks!
This gist code piece may help you.
https://gist.github.com/mayoff/4969104
It shows how to export frames into a gif image.
I don't believe there is any existing library that would do a straight conversion for you. There's a lot of libraries for displaying animated GIFs - far fewer native Objective-C libraries for creating them.
Fortunately, iOS does have support for saving as GIFs. There's an existing StackOverflow answer that covers how to create animated GIFs in-depth here:
Create and and export an animated gif via iOS?
...there's also a library on GitHub that abstracts the lower-level stuff away, although it's not been maintained for a while (link here).
All you'll need to do is create an array of the frames you want to convert into your GIF. I strongly recommend you don't try and convert every single frame in your 15 second video, if only because you'll end up with a very large GIF at a frame-rate that's too high. You would be better off picking every other, or even every 3/4 frames from your video sample. Capturing images from video is also pretty well documented on iOS.
I recently created a library called Regift for converting videos to gifs on iOS. Hopefully it will help anyone coming to this in the future :)
Actually I need a region over camera overlay like mostly of the QR code scanner app.
And when a square box comes within it just focus and click picture from it. Any idea how to implement it. I was using the UIIMAGEPICKER class but after doing some googling I found that I need to use the AVFoundation framework. But unfortunately I am not the near one.
Any code or any tutorial will be helpful. Please let me know how can I implement this.
One more thing if i need to take picture can i make the picture only to the region size?
Yes, you are correct. You will need to use AV Foundation to implement this. Have a look at the 'Using the Camera with AV Foundation' video from the WWDC 2010 session videos, to get an overview of the framework.
AvFoundation has no Dependancies on UIKit. So you will get some nice performance increases over using UIImagePickerController. It will also give you Full Access to the camera.
When using AV Foundation you are in control of the 'Device Capture Settings' i.e. Flash as well as Focus Mode and Exposure; including their points of interest. Have a look at the Programming Guide to see how to use these, or the device behaviour may differ from what you expected.
You can also download and example of an application that uses AV Foundation to implement the camera here.
Once you're up and running with that, have a look at this tutorial to get started with the overlay on the camera.
One more thing if i need to take picture can i make the picture only to the region size?
Yes you will be able to implement this. You can also configure the AVFoundation session itself to output the lowest practical resolution.
I want to integrate OCR in an iOS application. I have found some helpful tutorials, specially This Article: How To: Compile and Use Tesseract (3.01) on iOS (SDK 5), helped me a lot. Now I can read plain text from any image which has a clear background. But I want to read information from an ID card which doesn't have clear background at all!
I have also found some answers regarding removing background in stackoverflow, for example: Prepare complex image for OCR, Remove Background Color or Texture Before OCR Processing and How to use OpenCV to remove non text areas from a business card?
But those solutions are not for iOS. I understand the steps, but I need an iOS example and if it is using Core Image, than it would be better for me.
I have no problem in OCR end, but my problem is to remove the background.
Initial Image:
After removing, the image should look like this:
Can you refer me an iOS example? or Is it possible to refer me an iOS example to remove all the color without Black color?
the best way to detect a card in sence is traing a cascade classifier.
Training is not a very small project. the count of the sample images should be more thank 10K.
Once you get the trained cascade classifier, you can detect the the card quickly.
The detection is very quick on iOS, but the tesseract recognition is not very fast,
Im using ZXing, is working fine on my new app, but i would like to integrate the option of front or rear camera,
so far the only reference to this i've found is on the google group
But is not very clear what they mean with that,
so any pointers on what i have to do to accomplish this?
thanks !
ZXWidgetController doesn't provide that functionality and it's not really set up to make it easy to change.
The code that needs to change is in - (void)initCapture. It calls [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo]. This returns the default camera and you don't want the defalt.
You need code similar to that in - (ZXCaptureDevice*)device in ZXCapture.mm. That code won't work out of the box (it's designed to work with both AVFF and QTKit) but it's the same idea. Instead of using the default video input device, go through the devices and look at device position to find the device you want.
Be nice to port that code to the widget but that hasn't happened at this point.
I'm wanting to put together an application which plays video fullscreen with an interface overlaying it that basically chooses the video that is played underneath it (think 'Gym Babes' but nowhere near as risqé!). I don't wish to use private headers so MPMoviePlayerController is out of the question.
I've been digging through stackoverflow for a while and have come to the conclusion that I would need to use some sort of custom codec/video library that I assume would be written in C.
My question is basically has anyone had success doing this? And can anyone share any code, tutorials etc they can share?
You probably want to take a look at AVPlayerLayer: http://developer.apple.com/library/ios/documentation/AVFoundation/Reference/AVPlayerLayer_Class/Reference/Reference.html it gives you basic playback abilities with no (read fully customizable) interface…