7-segment LCD Display Reader 1.0
Free Version
Publisher Description
This is an OCR reader based on OpenCV. It can be used for recognizing 7-segments digitals (one line) on LCD display, such as calculator and electric meter. Compared with normal image, the LCD screen has a lower contrast and special processing solution is quite necessary for successful recognition.
I tested it under different lighting conditions and devices. The code can be checked out from following link and you can find more details in the comments.
https://github.com/yuyang551003/OpenCV_OCR_demo
NOTE: before running my apk, please install “OpenCV Manager” first. It can be found in Google Play.
1. Overview
The OCR process has three main steps:
1) Use edge detection algorithm to get the contours in the image.
2) Locate the digitals using vertical projection information.
3) Recognize the digitals based on their structure characteristics through a traversal method.
2. Details
2.1 Edge detection
I use Canny detection algorithm to get the contour information and the result looks very good.
2.2 Vertical projection
After getting the contours information, I scan vertically to get the vertical projection of the image in the “locating box”. The box is used to help locate digital area approximately (the user only need to put the digitals in the box when scanning). The projection value is actually the number of white points in vertical direction. Obviously, the projection value between two digitals is lower. Thus, based on the information, we can locate every digital.
2.3 Traversal method
After finding the positions of the digitals, we will traverse every digital from three different directions and then recognize them based the traversal results. See the example of digital “3” in the last figure. When we traverse the digital along line a, b and c, the number of passed segments should be 3, 1 and 1 respectively. Thus the recognition code of “3” is “311”. That is, for an unknown digital, if its code is “311”, it might be digital “3”.
About 7-segment LCD Display Reader
7-segment LCD Display Reader is a free app for Android published in the System Maintenance list of apps, part of System Utilities.
The company that develops 7-segment LCD Display Reader is Yu Yang. The latest version released by its developer is 1.0. This app was rated by 1 users of our site and has an average rating of 1.0.
To install 7-segment LCD Display Reader on your Android device, just click the green Continue To App button above to start the installation process. The app is listed on our website since 2014-07-31 and was downloaded 157 times. We have already checked if the download link is safe, however for your own protection we recommend that you scan the downloaded app with your antivirus. Your antivirus may detect the 7-segment LCD Display Reader as malware as malware if the download link to com.yuyang.opencvtest is broken.
How to install 7-segment LCD Display Reader on your Android device:
- Click on the Continue To App button on our website. This will redirect you to Google Play.
- Once the 7-segment LCD Display Reader is shown in the Google Play listing of your Android device, you can start its download and installation. Tap on the Install button located below the search bar and to the right of the app icon.
- A pop-up window with the permissions required by 7-segment LCD Display Reader will be shown. Click on Accept to continue the process.
- 7-segment LCD Display Reader will be downloaded onto your device, displaying a progress. Once the download completes, the installation will start and you'll get a notification after the installation is finished.
