Android MRZ Scanner using USB Camera
Feb 25, 2025
In the previous article, we talked about how to scan barcodes using a USB camera on an Android device. In this article, we are going to scan MRZ (machine-readable zone) on passports and ID cards with Dynamsoft Label Recognizer.
Here is a video of the result:
New Project
Open Android Studio to create a new Java project.
Add dependencies
-
Add the UVCCamera library.
-
Download the following AARs and put them in the
app/libsfolder. -
In
settings.gradle, add the following lines:dependencyResolutionManagement { repositories { google() mavenCentral() maven { url 'https://raw.github.com/saki4510t/libcommon/master/repository/' } flatDir { dirs 'libs' } } } -
In the app’s
build.gradle, add the following lines:dependencies { implementation fileTree(dir: 'libs', include: ['*.aar','*.jar']) implementation("com.serenegiant:common:1.5.20") { exclude module: 'support-v4' } } -
You may also need to enable Jetifier in
gradle.properties.android.enableJetifier=true
-
-
Add the Dynamsoft SDK.
-
In
settings.gradle, add the following lines:dependencyResolutionManagement { repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS) repositories { maven { url "https://download2.dynamsoft.com/maven/aar" } } } -
In the app’s
build.gradle, add the following lines:dependencies { implementation "com.dynamsoft:dynamsoftcapturevisionbundle:2.6.1002" implementation 'com.dynamsoft:dynamsoftmrz:3.4.20' }
-
Open the USB Camera
Let’s do the following to open the connected USB camera.
Add Controls
Add a UVCCameraTextureView for camera preview and an ImageButton to select and open cameras.
XML:
<com.serenegiant.widget.UVCCameraTextureView
android:id="@+id/camera_view"
android:layout_width="407dp"
android:layout_height="720dp"
android:layout_centerInParent="true"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<ImageButton
android:id="@+id/imageButton"
android:layout_width="50dp"
android:layout_height="50dp"
android:layout_marginBottom="16dp"
android:background="@android:color/transparent"
android:scaleType="fitCenter"
android:src="@android:drawable/ic_menu_camera"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent" />
In MainActivity:
private CameraViewInterface mUVCCameraView;
private ImageButton mCameraButton;
@Override
protected void onCreate(final Bundle savedInstanceState) {
//......
mCameraButton = findViewById(R.id.imageButton);
final View view = findViewById(R.id.camera_view);
mUVCCameraView = (CameraViewInterface)view;
}
Monitor USB Events
-
Initialize a USBMonitor instance.
private USBMonitor mUSBMonitor; @Override protected void onCreate(Bundle savedInstanceState) { //...... mUSBMonitor = new USBMonitor(this, mOnDeviceConnectListener); } private final USBMonitor.OnDeviceConnectListener mOnDeviceConnectListener = new USBMonitor.OnDeviceConnectListener() { @Override public void onAttach(final UsbDevice device) { Toast.makeText(MainActivity.this, "USB_DEVICE_ATTACHED", Toast.LENGTH_SHORT).show(); } @Override public void onConnect(final UsbDevice device, final USBMonitor.UsbControlBlock ctrlBlock, final boolean createNew) { } @Override public void onDisconnect(final UsbDevice device, final USBMonitor.UsbControlBlock ctrlBlock) { } @Override public void onDettach(final UsbDevice device) { Toast.makeText(MainActivity.this, "USB_DEVICE_DETACHED", Toast.LENGTH_SHORT).show(); } @Override public void onCancel(final UsbDevice device) { } }; -
Manage the life cycle.
@Override protected void onStart() { super.onStart(); mUSBMonitor.register(); } @Override protected void onStop() { mUSBMonitor.unregister(); super.onStop(); } @Override public void onDestroy() { if (mUSBMonitor != null) { mUSBMonitor.destroy(); mUSBMonitor = null; } super.onDestroy(); }
Start the Camera
The UVCCameraHandler class is used to handle USB cameras.
-
Initialize the handler.
/** * set true if you want to record movie using MediaSurfaceEncoder * (writing frame data into Surface camera from MediaCodec * by almost same way as USBCameratest2) * set false if you want to record movie using MediaVideoEncoder */ private static final boolean USE_SURFACE_ENCODER = false; /** * preview resolution(width) * if your camera does not support specific resolution and mode, * {@link UVCCamera#setPreviewSize(int, int, int)} throw exception */ private static final int PREVIEW_WIDTH = 640; // 640 /** * preview resolution(height) * if your camera does not support specific resolution and mode, * {@link UVCCamera#setPreviewSize(int, int, int)} throw exception */ private static final int PREVIEW_HEIGHT = 480; //480 /** * preview mode * if your camera does not support specific resolution and mode, * {@link UVCCamera#setPreviewSize(int, int, int)} throw exception * 0:YUYV, other:MJPEG */ private static final int PREVIEW_MODE = 0; // YUV private UVCCameraHandler mCameraHandler; @Override protected void onCreate(Bundle savedInstanceState) { //...... mCameraHandler = UVCCameraHandler.createHandler(this, mUVCCameraView, USE_SURFACE_ENCODER ? 0 : 1, PREVIEW_WIDTH, PREVIEW_HEIGHT, PREVIEW_MODE); } -
Add an
OnClickListenerfor the image button to start a camera selection dialog. The preview will be started after a camera is chosen.protected void onCreate(Bundle savedInstanceState) { //...... mCameraButton.setOnClickListener(mOnClickListener); //...... } private final View.OnClickListener mOnClickListener = new View.OnClickListener() { @Override public void onClick(final View view) { if ((mCameraHandler != null) && !mCameraHandler.isOpened()) { CameraDialog.showDialog(MainActivity.this); } else { mCameraHandler.close(); } } }; private final USBMonitor.OnDeviceConnectListener mOnDeviceConnectListener = new USBMonitor.OnDeviceConnectListener() { @Override public void onConnect(final UsbDevice device, final USBMonitor.UsbControlBlock ctrlBlock, final boolean createNew) { if (mCameraHandler != null) { mCameraHandler.open(ctrlBlock); startPreview(); } } } private void startPreview() { if (mCameraHandler != null) { final SurfaceTexture st = mUVCCameraView.getSurfaceTexture(); mCameraHandler.startPreview(new Surface(st)); } }The activity has to be modified as well to implements the library’s
CameraDialogParent:public class MainActivity extends BaseActivity implements CameraDialog.CameraDialogParentYou may find that the preview is distorted to fill the screen. You can keep its aspect ratio using the following code:
mUVCCameraView.setAspectRatio(PREVIEW_WIDTH / (double)PREVIEW_HEIGHT);
Read MRZ from USB Camera Preview
Now that we can show camera preview, we can use Dynamsoft Label Recognizer to scan MRZ.
Initialize the SDK
Initialize the SDK with a license. You can apply for a 30-day free trial license here.
private CaptureVisionRouter mRouter; //used to call Dynamsoft Label Recognizer to recognize MRZ
private CodeParser mParser; //used to parse the recognized MRZ
protected void onCreate(Bundle savedInstanceState) {
//......
if (savedInstanceState == null) {
LicenseManager.initLicense("LICENSE-KEY", this, (isSuccess, error) -> {
if (!isSuccess) {
error.printStackTrace();
}
});
}
mRouter = new CaptureVisionRouter(this);
mParser = new CodeParser(this);
}
Update the Setting to Recognize MRZ
We need to update the default settings for MRZ recognition with the following JSON template.
private void initMRZSettings(){
String template = """
{
"CaptureVisionTemplates": [
{
"Name": "Default"
},
{
"Name": "ReadBarcodes_Default",
"ImageROIProcessingNameArray": [
"roi_read_barcodes"
],
"Timeout": 200,
"MaxParallelTasks":0
},
{
"Name": "RecognizeTextLines_Default",
"ImageROIProcessingNameArray": [
"roi_recognize_number_letter"
],
"MaxParallelTasks":0
},
{
"Name": "DetectDocumentBoundaries_Default",
"ImageROIProcessingNameArray": [
"roi_detect_document_boundaries"
]
},
{
"Name": "DetectAndNormalizeDocument_Default",
"ImageROIProcessingNameArray": [
"roi_detect_and_normalize_document"
]
},
{
"Name": "NormalizeDocument_Default",
"ImageROIProcessingNameArray": [
"roi_normalize_document"
]
},
{
"Name": "ReadBarcodes_SpeedFirst",
"ImageROIProcessingNameArray": [
"roi_read_barcodes_speed_first"
],
"Timeout": 500
},
{
"Name": "ReadBarcodes_ReadRateFirst",
"ImageROIProcessingNameArray": [
"roi_read_barcodes_read_rate"
],
"Timeout": 5000
},
{
"Name": "ReadSingleBarcode",
"ImageROIProcessingNameArray": [
"roi_read_single_barcode"
],
"Timeout": 200,
"MaxParallelTasks":0
},
{
"Name": "RecognizeNumbers",
"ImageROIProcessingNameArray": [
"roi_recognize_number"
],
"MaxParallelTasks":0
},
{
"Name": "RecognizeLetters",
"ImageROIProcessingNameArray": [
"roi_recognize_letter"
],
"MaxParallelTasks":0
},
{
"Name": "RecognizeUppercaseLetters",
"ImageROIProcessingNameArray": [
"roi_recognize_uppercase"
],
"MaxParallelTasks":0
},
{
"Name": "RecognizeNumbersAndUppercaseLetters",
"ImageROIProcessingNameArray": [
"roi_recognize_number_uppercase"
],
"MaxParallelTasks":0
},
{
"Name": "RecognizeNumbersAndLetters",
"ImageROIProcessingNameArray": [
"roi_recognize_number_letter"
],
"MaxParallelTasks":0
},
{
"Name": "ReadPassportAndId",
"OutputOriginalImage": 0,
"ImageROIProcessingNameArray": [
"roi_passport_and_id"
],
"Timeout": 2000
},
{
"Name": "ReadPassport",
"OutputOriginalImage": 0,
"ImageROIProcessingNameArray": [
"roi_passport"
],
"Timeout": 2000
},
{
"Name": "ReadId",
"OutputOriginalImage": 0,
"ImageROIProcessingNameArray": [
"roi_id"
],
"Timeout": 2000
},
{
"Name" : "ReadDriversLicense",
"ImageROIProcessingNameArray" :
[
"roi_pdf_417"
],
"SemanticProcessingNameArray": [ "sp_pdf_417" ],
"Timeout" : 10000
},
{
"Name": "ReadVIN",
"ImageROIProcessingNameArray": [
"roi_vin_barcode",
"roi_vin_text"
],
"MaxParallelTasks": 4,
"SemanticProcessingNameArray": [
"sp_vin_barcode",
"sp_vin_text"
],
"Timeout": 10000
},
{
"Name" : "ReadVINBarcode",
"ImageROIProcessingNameArray" :
[
"roi_vin_barcode"
],
"MaxParallelTasks" : 4,
"SemanticProcessingNameArray": [ "sp_vin_barcode" ],
"Timeout" : 10000
},
{
"Name" : "ReadVINText",
"ImageROIProcessingNameArray" :
[
"roi_vin_text"
],
"MaxParallelTasks" : 4,
"SemanticProcessingNameArray": [ "sp_vin_text" ],
"Timeout" : 10000
}
],
"TargetROIDefOptions": [
{
"Name": "roi_read_barcodes",
"TaskSettingNameArray": [
"task_read_barcodes"
]
},
{
"Name": "roi_detect_document_boundaries",
"TaskSettingNameArray": [
"task_detect_document_boundaries"
]
},
{
"Name": "roi_detect_and_normalize_document",
"TaskSettingNameArray": [
"task_detect_and_normalize_document"
]
},
{
"Name": "roi_normalize_document",
"TaskSettingNameArray": [
"task_normalize_document"
]
},
{
"Name": "roi_read_barcodes_speed_first",
"TaskSettingNameArray": [
"task_read_barcodes_speed_first"
]
},
{
"Name": "roi_read_barcodes_read_rate",
"TaskSettingNameArray": [
"task_read_barcodes_read_rate"
]
},
{
"Name": "roi_read_single_barcode",
"TaskSettingNameArray": [
"task_read_single_barcode"
]
},
{
"Name": "roi_recognize_number",
"TaskSettingNameArray": [
"task_recognize_number"
]
},
{
"Name": "roi_recognize_letter",
"TaskSettingNameArray": [
"task_recognize_letter"
]
},
{
"Name": "roi_recognize_uppercase",
"TaskSettingNameArray": [
"task_recognize_uppercase"
]
},
{
"Name": "roi_recognize_number_uppercase",
"TaskSettingNameArray": [
"task_recognize_number_uppercase"
]
},
{
"Name": "roi_recognize_number_letter",
"TaskSettingNameArray": [
"task_recognize_number_letter"
]
},
{
"Name": "roi_passport_and_id",
"TaskSettingNameArray": [
"task_passport_and_id"
]
},
{
"Name": "roi_passport",
"TaskSettingNameArray": [
"task_passport"
]
},
{
"Name": "roi_id",
"TaskSettingNameArray": [
"task_id"
]
},
{
"Name" : "roi_pdf_417",
"TaskSettingNameArray" :
[
"task_pdf_417"
]
},
{
"Name" : "roi_vin_barcode",
"TaskSettingNameArray" :
[
"task_vin_barcode"
]
},
{
"Name" : "roi_vin_text",
"TaskSettingNameArray" :
[
"task_vin_text"
]
}
],
"BarcodeFormatSpecificationOptions": [
{
"Name": "bfs1",
"BarcodeFormatIds": [
"BF_PDF417",
"BF_QR_CODE",
"BF_DATAMATRIX",
"BF_AZTEC",
"BF_MICRO_QR",
"BF_MICRO_PDF417",
"BF_DOTCODE"
],
"MirrorMode": "MM_BOTH"
},
{
"Name": "bfs2",
"BarcodeFormatIds": [
"BF_ALL"
],
"MirrorMode": "MM_NORMAL"
},
{
"Name": "bfs1_speed_first",
"BaseBarcodeFormatSpecification": "bfs1"
},
{
"Name": "bfs2_speed_first",
"BaseBarcodeFormatSpecification": "bfs2"
},
{
"Name": "bfs1_read_rate_first",
"BaseBarcodeFormatSpecification": "bfs1"
},
{
"Name": "bfs2_read_rate_first",
"BaseBarcodeFormatSpecification": "bfs2"
},
{
"Name": "bfs1_single_barcode",
"BaseBarcodeFormatSpecification": "bfs1"
},
{
"Name": "bfs2_single_barcode",
"BaseBarcodeFormatSpecification": "bfs2"
},
{
"BarcodeFormatIds" :
[
"BF_CODE_39_EXTENDED"
],
"BarcodeTextRegExPattern" : "(I{0,1})([0-9A-HJ-NPR-Z]{9}[1-9A-HJ-NPR-TV-Y][0-9A-HJ-NPR-Z]{2}[0-9]{5})",
"MirrorMode" : "MM_NORMAL",
"ModuleSizeRangeArray" : null,
"Name" : "VIN_CODE_39_EXTENDED"
},
{
"BarcodeFormatIds" :
[
"BF_DATAMATRIX"
],
"BarcodeTextRegExPattern" : "[0-9A-HJ-NPR-Z]{9}[1-9A-HJ-NPR-TV-Y][0-9A-HJ-NPR-Z]{2}[0-9]{5}",
"Name" : "VIN_DATAMATRIX"
},
{
"BarcodeFormatIds" :
[
"BF_QR_CODE"
],
"Name" : "VIN_QR_CODE"
}
],
"BarcodeReaderTaskSettingOptions": [
{
"Name": "task_read_barcodes",
"ExpectedBarcodesCount" : 1,
"BaseBarcodeReaderTaskSettingName": "task_read_single_barcode",
"BarcodeFormatSpecificationNameArray": [
"bfs1",
"bfs2"
],
"LocalizationModes": [
{
"Mode": "LM_CONNECTED_BLOCKS"
},
{
"Mode": "LM_LINES"
}
],
"SectionImageParameterArray": [
{
"Section": "ST_REGION_PREDETECTION",
"ImageParameterName": "ip_read_barcodes"
},
{
"Section": "ST_BARCODE_LOCALIZATION",
"ImageParameterName": "ip_read_barcodes"
},
{
"Section": "ST_BARCODE_DECODING",
"ImageParameterName": "ip_read_barcodes"
}
]
},
{
"Name": "task_read_barcodes_speed_first",
"ExpectedBarcodesCount" : 0,
"BarcodeFormatIds" : [ "BF_DEFAULT" ],
"LocalizationModes": [
{
"Mode": "LM_CONNECTED_BLOCKS"
}
],
"DeblurModes":[
{
"Mode": "DM_BASED_ON_LOC_BIN"
},
{
"Mode": "DM_THRESHOLD_BINARIZATION"
},
{
"Mode": "DM_DEEP_ANALYSIS"
}
],
"BarcodeFormatSpecificationNameArray": [
"bfs1_speed_first",
"bfs2_speed_first"
],
"SectionImageParameterArray": [
{
"Section": "ST_REGION_PREDETECTION",
"ImageParameterName": "ip_read_barcodes_speed_first"
},
{
"Section": "ST_BARCODE_LOCALIZATION",
"ImageParameterName": "ip_read_barcodes_speed_first"
},
{
"Section": "ST_BARCODE_DECODING",
"ImageParameterName": "ip_read_barcodes_speed_first"
}
]
},
{
"Name": "task_read_barcodes_read_rate",
"ExpectedBarcodesCount" : 999,
"BarcodeFormatIds" : [ "BF_DEFAULT" ],
"LocalizationModes": [
{
"Mode" : "LM_CONNECTED_BLOCKS"
},
{
"Mode" : "LM_LINES"
},
{
"Mode" : "LM_STATISTICS"
}
],
"DeblurModes":[
{
"Mode": "DM_BASED_ON_LOC_BIN"
},
{
"Mode": "DM_THRESHOLD_BINARIZATION"
},
{
"Mode": "DM_DIRECT_BINARIZATION"
},
{
"Mode": "DM_SMOOTHING"
},
{
"Mode": "DM_DEEP_ANALYSIS"
}
],
"BarcodeFormatSpecificationNameArray": [
"bfs1_read_rate_first",
"bfs2_read_rate_first"
],
"SectionImageParameterArray": [
{
"Section": "ST_REGION_PREDETECTION",
"ImageParameterName": "ip_read_barcodes_read_rate"
},
{
"Section": "ST_BARCODE_LOCALIZATION",
"ImageParameterName": "ip_read_barcodes_read_rate"
},
{
"Section": "ST_BARCODE_DECODING",
"ImageParameterName": "ip_read_barcodes_read_rate"
}
]
},
{
"Name": "task_read_single_barcode",
"ExpectedBarcodesCount":1,
"LocalizationModes": [
{
"Mode": "LM_SCAN_DIRECTLY",
"ScanDirection": 2
},
{
"Mode": "LM_CONNECTED_BLOCKS"
}
],
"DeblurModes":[
{
"Mode": "DM_BASED_ON_LOC_BIN"
},
{
"Mode": "DM_THRESHOLD_BINARIZATION"
},
{
"Mode": "DM_DEEP_ANALYSIS"
}
],
"BarcodeFormatSpecificationNameArray": [
"bfs1_single_barcode",
"bfs2_single_barcode"
],
"SectionImageParameterArray": [
{
"Section": "ST_REGION_PREDETECTION",
"ImageParameterName": "ip_read_single_barcode"
},
{
"Section": "ST_BARCODE_LOCALIZATION",
"ImageParameterName": "ip_read_single_barcode"
},
{
"Section": "ST_BARCODE_DECODING",
"ImageParameterName": "ip_read_single_barcode"
}
]
},
{
"Name" : "task_pdf_417",
"BarcodeColourModes" :
[
{
"LightReflection" : 1,
"Mode" : "BICM_DARK_ON_LIGHT"
}
],
"BarcodeFormatIds" :
[
"BF_PDF417"
],
"DeblurModes" : null,
"ExpectedBarcodesCount" : 1,
"LocalizationModes" :
[
{
"Mode" : "LM_CONNECTED_BLOCKS"
},
{
"Mode" : "LM_LINES"
},
{
"Mode" : "LM_STATISTICS"
}
],
"SectionImageParameterArray" :
[
{
"ContinueWhenPartialResultsGenerated" : 1,
"ImageParameterName" : "ip_localize_pdf417",
"Section" : "ST_REGION_PREDETECTION"
},
{
"ContinueWhenPartialResultsGenerated" : 1,
"ImageParameterName" : "ip_localize_pdf417",
"Section" : "ST_BARCODE_LOCALIZATION"
},
{
"ContinueWhenPartialResultsGenerated" : 1,
"ImageParameterName" : "ip_decode_pdf417",
"Section" : "ST_BARCODE_DECODING"
}
]
},
{
"Name" : "task_vin_barcode",
"DeblurModes" : null,
"BarcodeColourModes" :
[
{
"LightReflection" : 1,
"Mode" : "BICM_DARK_ON_LIGHT"
}
],
"BarcodeFormatIds" :
[
"BF_CODE_39_EXTENDED",
"BF_QR_CODE",
"BF_DATAMATRIX"
],
"BarcodeFormatSpecificationNameArray" :
[
"VIN_CODE_39_EXTENDED",
"VIN_QR_CODE",
"VIN_DATAMATRIX"
],
"DeformationResistingModes" :
[
{
"BinarizationMode" :
{
"BinarizationThreshold" : -1,
"BlockSizeX" : 0,
"BlockSizeY" : 0,
"EnableFillBinaryVacancy" : 0,
"GrayscaleEnhancementModesIndex" : -1,
"Mode" : "BM_LOCAL_BLOCK",
"MorphOperation" : "Close",
"MorphOperationKernelSizeX" : -1,
"MorphOperationKernelSizeY" : -1,
"MorphShape" : "Rectangle",
"ThresholdCompensation" : 10
},
"GrayscaleEnhancementMode" :
{
"Mode" : "GEM_GENERAL",
"Sensitivity" : -1,
"SharpenBlockSizeX" : -1,
"SharpenBlockSizeY" : -1,
"SmoothBlockSizeX" : -1,
"SmoothBlockSizeY" : -1
},
"Level" : 5,
"Mode" : "DRM_SKIP"
}
],
"ExpectedBarcodesCount" : 1,
"LocalizationModes" :
[
{
"Mode" : "LM_CONNECTED_BLOCKS"
},
{
"Mode" : "LM_SCAN_DIRECTLY"
}
],
"SectionImageParameterArray" :
[
{
"ContinueWhenPartialResultsGenerated" : 1,
"ImageParameterName" : "ip_localize_vin",
"Section" : "ST_REGION_PREDETECTION"
},
{
"ContinueWhenPartialResultsGenerated" : 1,
"ImageParameterName" : "ip_localize_vin",
"Section" : "ST_BARCODE_LOCALIZATION"
},
{
"ContinueWhenPartialResultsGenerated" : 1,
"ImageParameterName" : "ip_decode_vin",
"Section" : "ST_BARCODE_DECODING"
}
]
}
],
"TextLineSpecificationOptions": [
{
"Name": "tls_number_letter",
"CharacterModelName" : "NumberLetter",
"OutputResults": 1
},
{
"Name": "tls_number",
"CharacterModelName" : "Number",
"OutputResults": 1
},
{
"Name": "tls_letter",
"CharacterModelName" : "Letter",
"OutputResults": 1
},
{
"Name": "tls_uppercase",
"CharacterModelName" : "Uppercase",
"OutputResults": 1
},
{
"Name": "tls_number_uppercase",
"CharacterModelName" : "NumberUppercase",
"OutputResults": 1
},
{
"Name": "tls_mrz_passport",
"BaseTextLineSpecificationName": "tls_base",
"StringLengthRange": [ 44, 44 ],
"OutputResults": 1,
"ExpectedGroupsCount": 1,
"ConcatResults": 1,
"ConcatSeparator": "\\n",
"SubGroups": [
{
"StringRegExPattern": "(P[A-Z<][A-Z<]{3}[A-Z<]{39}){(44)}",
"StringLengthRange": [ 44, 44 ],
"BaseTextLineSpecificationName": "tls_base"
},
{
"StringRegExPattern": "([A-Z0-9<]{9}[0-9][A-Z<]{3}[0-9]{2}[(01-12)][(01-31)][0-9][MF<][0-9]{2}[(01-12)][(01-31)][0-9][A-Z0-9<]{14}[0-9<][0-9]){(44)}",
"StringLengthRange": [ 44, 44 ],
"BaseTextLineSpecificationName": "tls_base"
}
]
},
{
"Name": "tls_mrz_id_td2",
"BaseTextLineSpecificationName": "tls_base",
"StringLengthRange": [ 36, 36 ],
"OutputResults": 1,
"ExpectedGroupsCount": 1,
"ConcatResults": 1,
"ConcatSeparator": "\\n",
"SubGroups": [
{
"StringRegExPattern": "([ACI][A-Z<][A-Z<]{3}[A-Z<]{31}){(36)}",
"StringLengthRange": [ 36, 36 ],
"BaseTextLineSpecificationName": "tls_base"
},
{
"StringRegExPattern": "([A-Z0-9<]{9}[0-9][A-Z<]{3}[0-9]{2}[(01-12)][(01-31)][0-9][MF<][0-9]{2}[(01-12)][(01-31)][0-9][A-Z0-9<]{8}){(36)}",
"StringLengthRange": [ 36, 36 ],
"BaseTextLineSpecificationName": "tls_base"
}
]
},
{
"Name": "tls_mrz_id_td1",
"BaseTextLineSpecificationName": "tls_base",
"StringLengthRange": [ 30, 30 ],
"OutputResults": 1,
"ExpectedGroupsCount": 1,
"ConcatResults": 1,
"ConcatSeparator": "\\n",
"SubGroups": [
{
"StringRegExPattern": "([ACI][A-Z<][A-Z<]{3}[A-Z0-9<]{9}[0-9<][A-Z0-9<]{15}){(30)}",
"StringLengthRange": [ 30, 30 ],
"BaseTextLineSpecificationName": "tls_base"
},
{
"StringRegExPattern": "([0-9]{2}[(01-12)][(01-31)][0-9][MF<][0-9]{2}[(01-12)][(01-31)][0-9][A-Z<]{3}[A-Z0-9<]{11}[0-9]){(30)}",
"StringLengthRange": [ 30, 30 ],
"BaseTextLineSpecificationName": "tls_base"
},
{
"StringRegExPattern": "([A-Z<]{30}){(30)}",
"StringLengthRange": [ 30, 30 ],
"BaseTextLineSpecificationName": "tls_base"
}
]
},
{
"Name": "tls_base",
"CharacterModelName": "MRZ",
"CharHeightRange": [ 5, 1000, 1 ],
"BinarizationModes": [
{
"BlockSizeX": 30,
"BlockSizeY": 30,
"Mode": "BM_LOCAL_BLOCK",
"EnableFillBinaryVacancy": 0,
"ThresholdCompensation": 15
}
],
"ConfusableCharactersCorrection": {
"ConfusableCharacters": [
[ "0", "O" ],
[ "1", "I" ],
[ "5", "S" ]
],
"FontNameArray": [ "OCR_B" ]
}
},
{
"Name": "tls_vin_text",
"CharacterModelName": "VIN",
"StringRegExPattern": "[0-9A-HJ-NPR-Z]{9}[1-9A-HJ-NPR-TV-Y][0-9A-HJ-NPR-Z]{2}[0-9]{5}",
"CharHeightRange": [5, 1000, 1],
"StringLengthRange": [17, 17]
}
],
"LabelRecognizerTaskSettingOptions": [
{
"Name": "task_recognize_number_letter",
"TextLineSpecificationNameArray": [
"tls_number_letter"
],
"SectionImageParameterArray": [
{
"Section": "ST_REGION_PREDETECTION",
"ImageParameterName": "ip_recognize_number_letter"
},
{
"Section": "ST_TEXT_LINE_LOCALIZATION",
"ImageParameterName": "ip_recognize_number_letter"
},
{
"Section": "ST_TEXT_LINE_RECOGNITION",
"ImageParameterName": "ip_recognize_number_letter"
}
]
},
{
"Name": "task_recognize_number",
"TextLineSpecificationNameArray": [
"tls_number"
],
"SectionImageParameterArray": [
{
"Section": "ST_REGION_PREDETECTION",
"ImageParameterName": "ip_recognize_textline_number"
},
{
"Section": "ST_TEXT_LINE_LOCALIZATION",
"ImageParameterName": "ip_recognize_textline_number"
},
{
"Section": "ST_TEXT_LINE_RECOGNITION",
"ImageParameterName": "ip_recognize_textline_number"
}
]
},
{
"Name": "task_recognize_letter",
"TextLineSpecificationNameArray": [
"tls_letter"
],
"SectionImageParameterArray": [
{
"Section": "ST_REGION_PREDETECTION",
"ImageParameterName": "ip_recognize_letter"
},
{
"Section": "ST_TEXT_LINE_LOCALIZATION",
"ImageParameterName": "ip_recognize_letter"
},
{
"Section": "ST_TEXT_LINE_RECOGNITION",
"ImageParameterName": "ip_recognize_letter"
}
]
},
{
"Name": "task_recognize_uppercase",
"TextLineSpecificationNameArray": [
"tls_uppercase"
],
"SectionImageParameterArray": [
{
"Section": "ST_REGION_PREDETECTION",
"ImageParameterName": "ip_recognize_uppercase"
},
{
"Section": "ST_TEXT_LINE_LOCALIZATION",
"ImageParameterName": "ip_recognize_uppercase"
},
{
"Section": "ST_TEXT_LINE_RECOGNITION",
"ImageParameterName": "ip_recognize_uppercase"
}
]
},
{
"Name": "task_recognize_number_uppercase",
"TextLineSpecificationNameArray": [
"tls_number_uppercase"
],
"SectionImageParameterArray": [
{
"Section": "ST_REGION_PREDETECTION",
"ImageParameterName": "ip_recognize_number_uppercase"
},
{
"Section": "ST_TEXT_LINE_LOCALIZATION",
"ImageParameterName": "ip_recognize_number_uppercase"
},
{
"Section": "ST_TEXT_LINE_RECOGNITION",
"ImageParameterName": "ip_recognize_number_uppercase"
}
]
},
{
"Name": "task_passport",
"ConfusableCharactersPath": "ConfusableChars.data",
"TextLineSpecificationNameArray": ["tls_mrz_passport"],
"SectionImageParameterArray": [
{
"Section": "ST_REGION_PREDETECTION",
"ImageParameterName": "ip_mrz"
},
{
"Section": "ST_TEXT_LINE_LOCALIZATION",
"ImageParameterName": "ip_mrz"
},
{
"Section": "ST_TEXT_LINE_RECOGNITION",
"ImageParameterName": "ip_mrz"
}
]
},
{
"Name": "task_id",
"ConfusableCharactersPath": "ConfusableChars.data",
"TextLineSpecificationNameArray": ["tls_mrz_id_td1", "tls_mrz_id_td2"],
"SectionImageParameterArray": [
{
"Section": "ST_REGION_PREDETECTION",
"ImageParameterName": "ip_mrz"
},
{
"Section": "ST_TEXT_LINE_LOCALIZATION",
"ImageParameterName": "ip_mrz"
},
{
"Section": "ST_TEXT_LINE_RECOGNITION",
"ImageParameterName": "ip_mrz"
}
]
},
{
"Name": "task_passport_and_id",
"ConfusableCharactersPath": "ConfusableChars.data",
"TextLineSpecificationNameArray": ["tls_mrz_passport", "tls_mrz_id_td1", "tls_mrz_id_td2"],
"SectionImageParameterArray": [
{
"Section": "ST_REGION_PREDETECTION",
"ImageParameterName": "ip_mrz"
},
{
"Section": "ST_TEXT_LINE_LOCALIZATION",
"ImageParameterName": "ip_mrz"
},
{
"Section": "ST_TEXT_LINE_RECOGNITION",
"ImageParameterName": "ip_mrz"
}
]
},
{
"Name": "task_vin_text",
"TextLineSpecificationNameArray": [
"tls_vin_text"
],
"SectionImageParameterArray": [
{
"Section": "ST_REGION_PREDETECTION",
"ImageParameterName": "ip_recognize_vin"
},
{
"Section": "ST_TEXT_LINE_LOCALIZATION",
"ImageParameterName": "ip_recognize_vin"
},
{
"Section": "ST_TEXT_LINE_RECOGNITION",
"ImageParameterName": "ip_recognize_vin"
}
]
}
],
"DocumentNormalizerTaskSettingOptions": [
{
"Name": "task_detect_and_normalize_document",
"SectionImageParameterArray": [
{
"Section": "ST_REGION_PREDETECTION",
"ImageParameterName": "ip_detect_and_normalize"
},
{
"Section": "ST_DOCUMENT_DETECTION",
"ImageParameterName": "ip_detect_and_normalize"
},
{
"Section": "ST_DOCUMENT_NORMALIZATION",
"ImageParameterName": "ip_detect_and_normalize"
}
]
},
{
"Name": "task_detect_document_boundaries",
"TerminateSetting": {
"Section": "ST_DOCUMENT_DETECTION"
},
"SectionImageParameterArray": [
{
"Section": "ST_REGION_PREDETECTION",
"ImageParameterName": "ip_detect"
},
{
"Section": "ST_DOCUMENT_DETECTION",
"ImageParameterName": "ip_detect"
},
{
"Section": "ST_DOCUMENT_NORMALIZATION",
"ImageParameterName": "ip_detect"
}
]
},
{
"Name": "task_normalize_document",
"StartSection": "ST_DOCUMENT_NORMALIZATION",
"SectionImageParameterArray": [
{
"Section": "ST_REGION_PREDETECTION",
"ImageParameterName": "ip_normalize"
},
{
"Section": "ST_DOCUMENT_DETECTION",
"ImageParameterName": "ip_normalize"
},
{
"Section": "ST_DOCUMENT_NORMALIZATION",
"ImageParameterName": "ip_normalize"
}
]
}
],
"ImageParameterOptions": [
{
"Name": "ip_read_barcodes",
"BaseImageParameterName": "ip_read_single_barcode"
},
{
"Name" : "ip_localize_pdf417",
"BinarizationModes" :
[
{
"Mode" : "BM_LOCAL_BLOCK"
}
],
"GrayscaleEnhancementModes" :
[
{
"Mode" : "GEM_GENERAL"
}
]
},
{
"Name" : "ip_decode_pdf417",
"ScaleDownThreshold" : 99999
},
{
"Name": "ip_read_barcodes_speed_first",
"TextDetectionMode": {
"Mode": "TTDM_LINE",
"Direction": "UNKNOWN",
"Sensitivity": 3
},
"IfEraseTextZone": 1,
"BinarizationModes": [
{
"Mode": "BM_LOCAL_BLOCK",
"BlockSizeX": 0,
"BlockSizeY": 0,
"EnableFillBinaryVacancy": 0
}
]
},
{
"Name": "ip_read_barcodes_read_rate",
"TextDetectionMode": {
"Mode": "TTDM_LINE",
"Direction": "UNKNOWN",
"Sensitivity": 3
},
"IfEraseTextZone": 1,
"GrayscaleTransformationModes" : [
{
"Mode": "GTM_ORIGINAL"
},
{
"Mode": "GTM_INVERTED"
}
],
"ScaleDownThreshold" : 100000
},
{
"Name": "ip_read_single_barcode",
"TextDetectionMode": {
"Mode": "TTDM_LINE",
"Direction": "UNKNOWN",
"Sensitivity": 3
},
"IfEraseTextZone": 1,
"BinarizationModes": [
{
"Mode": "BM_LOCAL_BLOCK",
"BlockSizeX": 39,
"BlockSizeY": 39,
"EnableFillBinaryVacancy": 0
}
]
},
{
"Name": "ip_recognize_number_letter",
"TextDetectionMode": {
"Mode": "TTDM_LINE",
"Direction": "HORIZONTAL",
"CharHeightRange": [
20,
1000,
1
],
"Sensitivity": 7
}
},
{
"Name": "ip_recognize_textline_number",
"TextDetectionMode": {
"Mode": "TTDM_LINE",
"Direction": "HORIZONTAL",
"CharHeightRange": [
20,
1000,
1
],
"Sensitivity": 7
}
},
{
"Name": "ip_recognize_letter",
"TextDetectionMode": {
"Mode": "TTDM_LINE",
"Direction": "HORIZONTAL",
"CharHeightRange": [
20,
1000,
1
],
"Sensitivity": 7
}
},
{
"Name": "ip_recognize_uppercase",
"TextDetectionMode": {
"Mode": "TTDM_LINE",
"Direction": "HORIZONTAL",
"CharHeightRange": [
20,
1000,
1
],
"Sensitivity": 7
}
},
{
"Name": "ip_recognize_number_uppercase",
"TextDetectionMode": {
"Mode": "TTDM_LINE",
"Direction": "HORIZONTAL",
"CharHeightRange": [
20,
1000,
1
],
"Sensitivity": 7
}
},
{
"Name": "ip_detect_and_normalize",
"BinarizationModes": [
{
"Mode": "BM_LOCAL_BLOCK",
"BlockSizeX": 0,
"BlockSizeY": 0,
"EnableFillBinaryVacancy": 0
}
],
"TextDetectionMode": {
"Mode": "TTDM_WORD",
"Direction": "HORIZONTAL",
"Sensitivity": 7
}
},
{
"Name": "ip_detect",
"BinarizationModes": [
{
"Mode": "BM_LOCAL_BLOCK",
"BlockSizeX": 0,
"BlockSizeY": 0,
"EnableFillBinaryVacancy": 0
}
],
"TextDetectionMode": {
"Mode": "TTDM_WORD",
"Direction": "HORIZONTAL",
"Sensitivity": 7
}
},
{
"Name": "ip_normalize",
"BinarizationModes": [
{
"Mode": "BM_LOCAL_BLOCK",
"BlockSizeX": 0,
"BlockSizeY": 0,
"EnableFillBinaryVacancy": 0
}
],
"TextDetectionMode": {
"Mode": "TTDM_WORD",
"Direction": "HORIZONTAL",
"Sensitivity": 7
}
},
{
"Name": "ip_mrz",
"TextureDetectionModes": [
{
"Mode": "TDM_GENERAL_WIDTH_CONCENTRATION",
"Sensitivity": 8
}
],
"BinarizationModes": [
{
"EnableFillBinaryVacancy": 0,
"ThresholdCompensation": 21,
"Mode": "BM_LOCAL_BLOCK"
}
],
"TextDetectionMode": {
"Mode": "TTDM_LINE",
"CharHeightRange": [ 5, 1000, 1 ],
"Direction": "HORIZONTAL",
"Sensitivity": 7
}
},
{
"Name" : "ip_localize_vin",
"BinarizationModes" :
[
{
"Mode" : "BM_LOCAL_BLOCK",
"MorphOperation" : "Erode"
}
],
"GrayscaleEnhancementModes" :
[
{
"Mode" : "GEM_GENERAL",
"Sensitivity" : 5,
"SharpenBlockSizeX" : 3,
"SharpenBlockSizeY" : 3,
"SmoothBlockSizeX" : 3,
"SmoothBlockSizeY" : 3
}
],
"GrayscaleTransformationModes" :
[
{
"Mode" : "GTM_ORIGINAL"
},
{
"Mode" : "GTM_INVERTED"
}
]
},
{
"Name" : "ip_decode_vin",
"GrayscaleTransformationModes" :
[
{
"Mode" : "GTM_ORIGINAL"
}
],
"ScaleDownThreshold" : 99999
},
{
"Name": "ip_recognize_vin",
"TextDetectionMode": {
"Mode": "TTDM_LINE",
"Direction": "HORIZONTAL",
"CharHeightRange": [
5,
1000,
1
],
"Sensitivity": 7
},
"GrayscaleTransformationModes": [
{
"Mode": "GTM_ORIGINAL"
},
{
"Mode": "GTM_INVERTED"
}
],
"BinarizationModes" :
[
{
"EnableFillBinaryVacancy" : 1,
"Mode" : "BM_LOCAL_BLOCK"
}
]
}
\s
],
"CharacterModelOptions": [
{
"Name" : "Number"
},
{
"Name" : "Letter"
},
{
"Name" : "Uppercase"
},
{
"Name" : "NumberUppercase"
},
{
"Name" : "NumberLetter"
},
{
"Name": "MRZ"
},
{
"Name": "VIN"
}
],
"SemanticProcessingOptions": [
{
"Name": "sp_passport_and_id",
"ReferenceObjectFilter": {
"ReferenceTargetROIDefNameArray": [
"roi_passport_and_id"
]
},
"TaskSettingNameArray": [
"parse_passport_and_id"
]
},
{
"Name": "sp_passport",
"ReferenceObjectFilter": {
"ReferenceTargetROIDefNameArray": [
"roi_passport"
]
},
"TaskSettingNameArray": [
"parse_passport"
]
},
{
"Name": "sp_id",
"ReferenceObjectFilter": {
"ReferenceTargetROIDefNameArray": [
"roi_id"
]
},
"TaskSettingNameArray": [
"parse_id"
]
},
{
"Name": "sp_pdf_417",
"ReferenceObjectFilter": {
"ReferenceTargetROIDefNameArray": [
"roi_pdf_417"
]
},
"TaskSettingNameArray": [
"parse_pdf_417"
]
},
{
"Name": "sp_vin_barcode",
"ReferenceObjectFilter": {
"ReferenceTargetROIDefNameArray": [
"roi_vin_barcode"
]
},
"TaskSettingNameArray": [
"parse_vin_barcode"
]
},
{
"Name": "sp_vin_text",
"ReferenceObjectFilter": {
"ReferenceTargetROIDefNameArray": [
"roi_vin_text"
]
},
"TaskSettingNameArray": [
"parse_vin_text"
]
}
],
"CodeParserTaskSettingOptions": [
{
"Name": "parse_passport",
"CodeSpecifications": [ "MRTD_TD3_PASSPORT" ]
},
{
"Name": "parse_id",
"CodeSpecifications": [ "MRTD_TD1_ID", "MRTD_TD2_ID" ]
},
{
"Name": "parse_passport_and_id",
"CodeSpecifications": [ "MRTD_TD3_PASSPORT", "MRTD_TD1_ID", "MRTD_TD2_ID" ]
},
{
"Name": "parse_pdf_417",
"CodeSpecifications": ["AAMVA_DL_ID","AAMVA_DL_ID_WITH_MAG_STRIPE","SOUTH_AFRICA_DL"]
},
{
"Name": "parse_vin_barcode",
"CodeSpecifications": ["VIN"]
},
{
"Name": "parse_vin_text",
"CodeSpecifications": ["VIN"]
}
]
}
""";
try {
mRouter.initSettings(template);
} catch (CaptureVisionRouterException e) {
throw new RuntimeException(e);
}
}
We can also update the USB camera’s resolution by changing the PREVIEW_WIDTH and PREVIEW_HEIGHT. OCR requires a higher resolution.
Create a Timer to Process Frames
When a camera is connected, start processing using a timer.
private Timer timer = null;
private void startProcessing(){
TimerTask task = new TimerTask() {
@Override
public void run() {
Bitmap bmp = mUVCCameraView.captureStillImage();
recognize(bmp);
}
};
timer = new Timer();
timer.scheduleAtFixedRate(task, 1000, 100);
}
private void stopProcessing(){
if (timer != null){
timer.cancel();
timer = null;
}
}
private final USBMonitor.OnDeviceConnectListener mOnDeviceConnectListener = new USBMonitor.OnDeviceConnectListener() {
//......
@Override
public void onConnect(final UsbDevice device, final USBMonitor.UsbControlBlock ctrlBlock, final boolean createNew) {
if (mCameraHandler != null) {
mCameraHandler.open(ctrlBlock);
startPreview();
startProcessing(); //newly added
}
}
@Override
public void onDisconnect(final UsbDevice device, final USBMonitor.UsbControlBlock ctrlBlock) {
stopProcessing(); //newly added
}
}
The preview is captured as bitmap for the Dynamsoft SDK to process. The result will be displayed in a TextView.
private void recognize(final Bitmap bitmap){
try {
CapturedResult result = mRouter.capture(bitmap, "ReadPassportAndId"); //recognize MRZ
RecognizedTextLinesResult linesResult = result.getRecognizedTextLinesResult();
runOnUiThread(
new Runnable() {
@Override
public void run() {
if (linesResult != null) {
TextLineResultItem[] results = linesResult.getItems();
StringBuilder linesBuilder = new StringBuilder();
for (TextLineResultItem result : results){
linesBuilder.append(result.getText());
linesBuilder.append("\n");
}
try {
StringBuilder result = new StringBuilder();
ParsedResultItem item = mParser.parse(linesBuilder.toString().getBytes(StandardCharsets.UTF_8),""); //parse MRZ
for (HashMap.Entry<String, String> entry : item.getParsedFields().entrySet()) {
String key = entry.getKey();
String value = entry.getValue();
result.append(key).append(": ").append(value).append("\n");
}
resultTextView.setText(result.toString());
} catch (CodeParserException e) {
resultTextView.setText(e.getMessage());
}
}
}
}
);
} catch (Exception e){
e.printStackTrace();
}
}
Compatibility issue
On Android 9+, the library may not work if the targetSdkVersion is set larger than 27. You can check out this post to learn more.