Barcode reading using picture taken using mobile phone camera

Question

How do we do programmatic reading of a barcode that is captured using a mobile phone camera? For example, how do that using iPhone or Android or Java ME? Do we need separate hardware to read bar code or can we do image manipulation?

Answer 1

Obviously it's possible to read the bar code from an image of it. You probably need to think about issues like

• Orientation; perhaps the photo is not straight-on, so the bars aren't vertical. Also, it might be upside-down ...
• Focus; what if the shot is blurry? There probably is a limit where it becomes impossible to interpret it safely.
• Cropped; what if the framing is bad, so the entire code isn't even in the image?

There are lots of existing projects and products that solve this ... Here is one, for instance. Some solutions seem to not be very sensitive to points like those above, but claim to be able to find and recognize bar codes regardless of orientation and location in the image, for instance.

Answer 2

For Android it's very easy. Simply use the service provided by the Barcode Scanner app (dependancy). Then the Barcode Scanner app will handle all of the scanning part and will simply return you the code.

I think similar solutions are available for other platforms, but in Android it's even easier because of its Intent architecture.

Answer 3

Google has made this INCREDIBLY simple with their Zebra Crossing libraries. They have support for doing scanning via images on the following platforms:

• J2SE
• Android

and others have ported to:

• J2ME
• CSharp
• CPP
• Rim
• iPhone
• Bug

As another poster already mentioned, on Android you could also use an Intent to call Barcode Reader with something like:

public Button.OnClickListener mScan = new Button.OnClickListener() {
    public void onClick(View v) {
        Intent intent = new Intent("com.google.zxing.client.android.SCAN");
        intent.putExtra("SCAN_MODE", "ONE_D_MODE");
        startActivityForResult(intent, 0);
    }
};

public void onActivityResult(int requestCode, int resultCode, Intent intent) {
    if (requestCode == 0) {
        if (resultCode == RESULT_OK) {
            String contents = intent.getStringExtra("SCAN_RESULT");
            String format = intent.getStringExtra("SCAN_RESULT_FORMAT");
            // Handle successful scan
        } else if (resultCode == RESULT_CANCELED) {
            // Handle cancel
        }
    }
}

Answer 4

Barcodes can be read through analysis taken from phone cameras.

A well-known complication is that fixed-focus cameras (like on the older 2G/3G iPhones and some Androids) cannot take in-focus snapshot form short distances. To counter that, special de-convoluting algorithms have to be used - and last time i checked this was not part of the Zebra Crossing.

Some have implemented solutions - i am aware of the following apps for iPhone who can read UPCs with fixed-focus camera: pic2shop (Benoit Maison / Vision Smarts), RedLaser (Occipital) and ShopSavvy (Big in Japan) - check them out and i think all of them have available SDKs for interested 3rd parties.

Answer 5

I hope this will help you http://computersight.com/software/batoo-bar-code-toolkit-j2me/

Answer 6

You can do something similar to the Intent system on the iPhone.

To launch the free pic2shop barcode reader from a web page or another app, use the custom URL pic2shop://scan?callback=YOURURLHERE

As soon as the barcode is read, pic2shop will call the URL you specified (which can be a web app or an app's custom URL) with the barcode digits.

There is an online demo at http://www.pic2shop.com/demo/scan.html