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Explore the flexibe barcode reading settings to optimize for your specific usage scenario.

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Detects the machine-readable zone of a passport, scans the text, and parses into human-readable data.

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How to read barcodes with uneven lighting

In some scenarios, the captured barcode image may have inconsistent lighting across the barcode. For example, the following image shows a barcode image with uneven lighting.

Sample barcode image with uneven lighting

Figure 1 – Sample barcode image with uneven lighting

Converting the original barcode image to a binarized image is a very important step. DBR provides two binarization modes:

  • BM_THRESHOLD: uses a global threshold to binarize the image. If the gray value of the pixel is less than the threshold, it will be black in the binary image, otherwise it will be white.
  • BM_LOCAL_BLOCK: use a threshold for a pixel based on a small region around it.

The following two images show the effects of BM_THRESHOLD (global thresholding) and BM_LOCAL_BLOCK (local thresholding).

Binarized image by global thresholding

Figure 2 – Binarized image by global thresholding

Binarized image by local thresholding

Figure 3 – Binarized image by local thresholding

Obviously, the local thresholding result is much better. Now we will demonstrate how to configure the BinarizationModes to use the BM_LOCAL_BLOCK binarization.

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// Obtains the current runtime settings of DBR.
let rs = await scanner.getRuntimeSettings();
// Sets the binarization mode.
rs.binarizationModes[0] = Dynamsoft.DBR.EnumBinarizationMode.BM_LOCAL_BLOCK;
// Updates the settings.
await scanner.updateRuntimeSettings(rs);
// Fine-tunes some arguments of the first mode in `binarizationModes`
scanner.setModeArgument("binarizationModes", 0, "BlockSizeX", "0");
scanner.setModeArgument("binarizationModes", 0, "BlockSizeY", "0");
scanner.setModeArgument("binarizationModes", 0, "EnableFillBinaryVacancy", "1");
scanner.setModeArgument("binarizationModes", 0, "ThresholdCompensation", "10");
await scanner.show();
// Obtain current runtime settings of `reader` instance.
PublicRuntimeSettings settings = reader.getRuntimeSettings();
// Set a binarization mode
settings.binarizationModes = new int[]{ EnumBinarizationMode.BM_LOCAL_BLOCK };
// Update the settings.
reader.updateRuntimeSettings(settings);
// Fine-tune some arguments of the first mode in `binarizationModes`
reader.setModeArgument("binarizationModes", 0, "BlockSizeX", "0");
reader.setModeArgument("binarizationModes", 0, "BlockSizeY", "0");
reader.setModeArgument("binarizationModes", 0, "EnableFillBinaryVacancy", "1");
reader.setModeArgument("binarizationModes", 0, "ThresholdCompensation", "10");
NSError* err = nil;
// Obtain current runtime settings of `reader` instance.
iPublicRuntimeSettings* settings = [reader getRuntimeSettings:&err];
// Set a binarization mode
settings.binarizationModes = @[@(EnumBinarizationModeLocalBlock)];
// Update the settings.
[reader updateRuntimeSettings:settings error:&err];
// Fine-tune some arguments of the first mode in `binarizationModes`
[reader setModeArgument:@"binarizationModes" index:0 argumentName:@"BlockSizeX" argumentValue:@"0" error:nil];
[reader setModeArgument:@"binarizationModes" index:0 argumentName:@"BlockSizeY" argumentValue:@"0" error:nil];
[reader setModeArgument:@"binarizationModes" index:0 argumentName:@"EnableFillBinaryVacancy" argumentValue:@"1" error:nil];
[reader setModeArgument:@"binarizationModes" index:0 argumentName:@"ThresholdCompensation" argumentValue:@"10" error:nil];
// Obtain current runtime settings of `reader` instance.
let settings = try? reader.getRuntimeSettings()
// Set a binarization mode
settings?.binarizationModes = [EnumBinarizationMode.localBlock]
// Update the settings.
try? reader.updateRuntimeSettings(settings!)
// Fine-tune some arguments of the first mode in `binarizationModes`
try? reader.setModeArgument("binarizationModes", index: 0, argumentName: "BlockSizeX", argumentValue: "0")
try? reader.setModeArgument("binarizationModes", index: 0, argumentName: "BlockSizeY", argumentValue: "0")
try? reader.setModeArgument("binarizationModes", index: 0, argumentName: "EnableFillBinaryVacancy", argumentValue: "1")
try? reader.setModeArgument("binarizationModes", index: 0, argumentName: "ThresholdCompensation", argumentValue: "10")
error = BarcodeReader.init_license("YOUR-LICENSE-KEY")
if error[0] != EnumErrorCode.DBR_OK:
    print(error[1])
dbr = BarcodeReader()
settings = dbr.get_runtime_settings()
settings.binarization_modes[0] = EnumBinarizationMode.BM_LOCAL_BLOCK
dbr.update_runtime_settings(settings)
dbr.set_mode_argument("BinarizationModes", 0, "BlockSizeX", "0")
dbr.set_mode_argument("BinarizationModes", 0, "BlockSizeY", "0")
dbr.set_mode_argument("BinarizationModes", 0, "ThresholdCompensation", "10")
text_results = dbr.decode_file("YOUR-IMAGE-FILE-PATH")
# Add further process
BarcodeReader.initLicense("YOUR-LICENSE-KEY");
BarcodeReader reader = new BarcodeReader();
PublicRuntimeSettings settings = reader.getRuntimeSettings(); //Get the current RuntimeSettings
settings.binarizationModes[0] = EnumBinarizationMode.BM_LOCAL_BLOCK;
reader.updateRuntimeSettings(settings); // Update RuntimeSettings with above setting
reader.setModeArgument("BinarizationModes", 0, "BlockSizeX", "0");
reader.setModeArgument("BinarizationModes", 0, "BlockSizeY", "0");
reader.setModeArgument("BinarizationModes", 0, "ThresholdCompensation", "10");
TextResult[] result = reader.decodeFile("YOUR-IMAGE-FILE-PATH", ""); // Start decoding
// Add further process
string errorMsg;
EnumErrorCode iRet = BarcodeReader.InitLicense("YOUR-LICENSE-KEY", out errorMsg);
if (iRet != EnumErrorCode.DBR_SUCCESS)
{
    Console.WriteLine(errorMsg);
}
BarcodeReader reader = new BarcodeReader();
PublicRuntimeSettings settings = reader.GetRuntimeSettings(); //Get the current RuntimeSettings
settings.BinarizationModes[0] = EnumBinarizationMode.BM_LOCAL_BLOCK;
reader.UpdateRuntimeSettings(settings); // Update RuntimeSettings with above setting
reader.SetModeArgument("BinarizationModes", 0, "BlockSizeX", "0", out errorMsg);
reader.SetModeArgument("BinarizationModes", 0, "BlockSizeY", "0", out errorMsg);
reader.SetModeArgument("BinarizationModes", 0, "ThresholdCompensation", "10", out errorMsg);
TextResult[] result = reader.DecodeFile("YOUR-IMAGE-FILE-PATH", ""); // Start decoding
// Add further process
char errorBuf[512];
int iRet = -1;
iRet = dynamsoft::dbr::CBarcodeReader::InitLicense("YOUR-LICENSE-KEY", errorBuf, 512);
if (iRet != DBR_OK)
{
    cout << errorBuf << endl;
}
CBarcodeReader* reader = new CBarcodeReader();
PublicRuntimeSettings* runtimeSettings = new PublicRuntimeSettings();
reader->GetRuntimeSettings(runtimeSettings); //Get the current RuntimeSettings
runtimeSettings->binarizationModes[0] = BM_LOCAL_BLOCK;
reader->UpdateRuntimeSettings(runtimeSettings, errorBuf, 512); // Update RuntimeSettings with above setting
reader->SetModeArgument("BinarizationModes", 0, "BlockSizeX", "0", sError, 512);
reader->SetModeArgument("BinarizationModes", 0, "BlockSizeY", "0", sError, 512);
reader->SetModeArgument("BinarizationModes", 0, "ThresholdCompensation", "10", sError, 512);
reader->DecodeFile("YOUR-IMAGE-FILE-PATH", ""); // Start decoding
// Add further process
int iRet = -1;
char errorBuf[512];
iRet = DBR_InitLicense("YOUR-LICENSE-KEY", errorBuf, 512);
if (iRet != DBR_OK)
{
    printf("%s\n", errorBuf);
}
void* barcodeReader = DBR_CreateInstance();
PublicRuntimeSettings runtimeSettings;
DBR_GetRuntimeSettings(barcodeReader, &runtimeSettings); //Get the current RuntimeSettings
runtimeSettings.binarizationModes[0] = BM_LOCAL_BLOCK;
DBR_UpdateRuntimeSettings(barcodeReader, &runtimeSettings, errorBuf, 512); // Update RuntimeSettings with above setting
DBR_SetModeArgument(barcodeReader, "BinarizationModes", 0, "BlockSizeX", "0", sError, 512);
DBR_SetModeArgument(barcodeReader, "BinarizationModes", 0, "BlockSizeY", "0", sError, 512);
DBR_SetModeArgument(barcodeReader, "BinarizationModes", 0, "ThresholdCompensation", "10", sError, 512);
DBR_DecodeFile(barcodeReader, "YOUR-IMAGE-FILE-PATH", ""); // Start decoding
// Add further process

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