HOW TO: Improve mobile image OCR quality for better results

#1 Posted : Friday, June 28, 2019 3:43:35 PM(UTC)

Marcus Andra

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Provided below are two pictures that provide different output results

LEADTOOLS supports character recognition for many scenarios; however, you may find that the quality of recognition for images taken from your mobile devices are not as clear as you would hope.

We recommend image quality to be between 200 - 300 DPI when working with our SDK; however, this is not something you are able to control when using a mobile camera as your capture device. Once you have ensured that the images you are taking maintain at least 720 pixels, you can use one of our useful LEAD Engine settings to do the rest of the work for you.

Without

File Attachment(s):

NoPreprocess.pdf (4kb) downloaded 36 time(s).

With

File Attachment(s):

Preprocess.pdf (4kb) downloaded 41 time(s).

You will be using IOcrSettingManager to access the SetBooleanValue method in order to set "Recognition.Preprocess.MobileImagePreprocess" to true. By design most cameras take pictures in a low resolution, so it's important that you use this engine setting whenever you're expecting an input image from a mobile device. By default this value is set to false in order to conserve on memory; however, you'll want to use this option if you are using the OCR engine to process images from a mobile camera. You can see one way of doing this in the code below which is added immediately after starting the OCR Engine.

Code:

ocrEngine.Startup(null, null, null, LEAD_VARS.OcrLEADRuntimeDir);

IOcrSettingManager settingManager = ocrEngine.SettingManager;
settingManager.SetBooleanValue("Recognition.Preprocess.MobileImagePreprocess", true);

The original image can be seen attached below. For any additional questions not covered by this post, please email us at support@leadtools.com.

File Attachment(s):

original image.jpg (2,371kb) downloaded 51 time(s).

Edited by user Tuesday, July 2, 2019 4:04:10 PM(UTC) | Reason: Not specified

Marcus Andra
Developer Support Engineer
LEAD Technologies, Inc.

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HOW TO: Improve mobile image OCR quality for better results - How to get better recognition results from mobile pictures


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