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https://github.com/soranakk/outoffocusqrreader
OutOfFocusQRReader is a library for reading QR codes from out-of-focus images on Android.
https://github.com/soranakk/outoffocusqrreader
android opencv
Last synced: 6 days ago
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OutOfFocusQRReader is a library for reading QR codes from out-of-focus images on Android.
- Host: GitHub
- URL: https://github.com/soranakk/outoffocusqrreader
- Owner: soranakk
- License: apache-2.0
- Created: 2021-02-03T05:28:12.000Z (almost 4 years ago)
- Default Branch: main
- Last Pushed: 2021-04-02T15:22:22.000Z (over 3 years ago)
- Last Synced: 2024-10-12T16:22:57.915Z (about 1 month ago)
- Topics: android, opencv
- Language: Kotlin
- Homepage:
- Size: 3.99 MB
- Stars: 0
- Watchers: 1
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# OutOfFocusQRReader
OutOfFocusQRReader is a library for reading QR Code from out-of-focus images on Android.
This library uses the OpenCV library.
*“QR Code” is a registered trademark of DENSO WAVE INCORPORATED.*
# Install
## Download OpenCV
Download the latest version of the OpenCV Android library from the official OpenCV web page.
https://opencv.org/releases/
## Extract zip and move SDK folder
Extract the files the downloaded zip file and move the SDK folder to your project root folder.
## Install OpenCV SDK
Edit the `settings.gradle` file in your project and sync your project:
```gradle
// add
include ':sdk'
```
## Install OutOfFocusQRReader
Edit the `build.gradle` file in your project:
```gradle
repositories {
mavenCentral()
}
dependencies {
// OpenCV sdk
implementation project(':sdk')
// core
implementation 'com.github.soranakk.oofqrreader:oofqrreader:1.0.0'
}
```
# Usage
## Create ImageData
### Example using Camera2API
```gradle
dependencies {
...
implementation 'com.github.soranakk.oofqrreader:image-converter-android-camera:1.0.0'
}
```
```kotlin
val imageConverter = Camera2ApiImageConverter()
ImageReader.newInstance(width, height, ImageFormat.YUV_420_888, 1)
.apply {
setOnImageAvailableListener({ reader ->
reader?.acquireLatestImage()?.let { image ->
val imageData = imageConverter.convertImage(image)
... read QR Code
image.close()
}
}, workerHandler)
```
### Example using CameraXAPI
```gradle
dependencies {
...
implementation 'com.github.soranakk.oofqrreader:image-converter-androidx-camera:1.0.0'
}
```
```kotlin
val imageConverter = CameraXApiImageConverter()
val imageAnalysis = ImageAnalysis.Builder()
.setTargetRotation(Surface.ROTATION_0)
.setTargetResolution(Size(1280, 720))
.setBackpressureStrategy(ImageAnalysis.STRATEGY_KEEP_ONLY_LATEST)
.build()
.also {
it.setAnalyzer(cameraExecutor, ImageAnalysis.Analyzer { image ->
val imageData = imageConverter.convertImage(image)
... read QR Code
image.close()
})
}
```
## Create QRCodeDecoder
### Example using [MLKit](https://developers.google.com/ml-kit/vision/barcode-scanning/android):
```gradle
dependencies {
...
implementation 'com.github.soranakk.oofqrreader:decoder-mlkit:1.0.0'
implementation 'com.google.mlkit:barcode-scanning:16.1.1'
}
```
```kotlin
val mlKitDecoder = MLKitDecoder()
```
### Example using [ZXing](https://github.com/zxing/zxing):
```gradle
dependencies {
...
implementation 'com.github.soranakk.oofqrreader:decoder-zxing:1.0.0'
implementation "com.google.zxing:core:3.4.1"
}
```
```kotlin
val zxingDecoder = ZxingDecoder()
```
If your app require Android minSdkVersion less than 24,
see https://github.com/zxing/zxing/issues/1170 and demoApp's build.gradle
### Example using [OpenCV](https://opencv.org/):
```gradle
dependencies {
...
implementation 'com.github.soranakk.oofqrreader:decoder-opencv:1.0.0'
}
```
```kotlin
val openCVDecoder = OpenCVDecoder()
```
## Read QR code
```kotlin
val qrReader = MultiFilterQRCodeReader(someDecoder)
val result = qrReader.detectAndRead(image)
```
See demoApp for more info.
# Appendix
## How to improve accuracy
### Estimate the area where a QR code exist
Estimate the area where a QR code exists by using the large contrast between the QR code and the background.
1. Make the input image grayscale
2. Binarize with Otsu's method
3. Use `Imgproc.erode` to thicken the dots in a QR code and turn them into black squares.
4. Use `Imgproc.findContours` to get the black square area
### Adjust the image
Further improve the accuracy by processing the image of the estimated area using various Image Filters.
The features of each ImageFilter implemented are as follows.
#### GaussianThresholdFilter
Binarize with a weighted average using Gaussian as a threshold at a fixed block size.
Input image
Estimate the area where a QR code exists
After applying the image filter
#### ThresholdOtsuFilter
Binarize Otsu's method.
Input image
Estimate the area where a QR code exists
After applying the image filter
#### OverexposureFilter
A filter for reading overexposed QR codes by setting a threshold so that even almost white areas become black.
Most input images output a black image, but under certain circumstances this filter works well.
For example, displaying a QR code on a smartphone will result in overexposure due to the strong backlight of the smartphone.
Input image
Estimate the area where a QR code exists
After applying the image filter
