How to read high-density QR Codes

A QR code can store up to 7,089 numbers, 4,296 alphanumeric characters, 2,953 bytes, or 1,817 Japanese Kanjis. As the encoded information increases, the QR code becomes denser. The diagram below displays a QR code that has high density.

In some scenarios, high-density QR codes become more difficult to locate and recognize due to small barcode images, perspective, and distortion.

We can do the following to optimize the read rate of high-density QR codes:

• Scale up modules if they are too small
• Sharpen the image
• Run gray equalization

The following code snippet shows how to configure the parameters via a json template string.

• JavaScript
• Android
• Objective-C
• Swift
• Python
• Java
• C#
• C++
• C

const scanner = await Dynamsoft.DBR.BarcodeScanner.createInstance();
// Allow js to directly process 4K images in canvas without compressing them.
// Please test on the target devices. On devices with limited memory, the settings can lead to out of memory.
scanner.maxCvsSideLength = 4096;
// Defines settings for reading dense barcodes in a template.
let jsonString = "{\"ImageParameter\":{\"BarcodeComplementModes\":[\"BCM_SKIP\"],\"DeblurModes\":[{\"Mode\":\"DM_SHARPENING\"},{\"Mode\":\"DM_GRAY_EQUALIZATION\"}],\"ExpectedBarcodesCount\":1,\"LocalizationModes\":[\"LM_CONNECTED_BLOCKS\"],\"ScaleUpModes\":[\"SUM_LINEAR_INTERPOLATION(0,4,6)\"],\"MaxAlgorithmThreadCount\":1,\"Name\":\"high-density-qr-tpl\",\"ScaleDownThreshold\":10000,\"Timeout\":5000},\"Version\":\"3.0\"}";
// Configures the BarcodeScanner object with the settings.
await scanner.initRuntimeSettingsWithString(jsonString);
scanner.show();

String jsonPara = "{\"ImageParameter\":{\"BarcodeComplementModes\":[\"BCM_SKIP\"],\"DeblurModes\":[{\"Mode\":\"DM_SHARPENING\"},{\"Mode\":\"DM_GRAY_EQUALIZATION\"}],\"ExpectedBarcodesCount\":1,\"LocalizationModes\":[\"LM_CONNECTED_BLOCKS\"],\"ScaleUpModes\":[\"SUM_LINEAR_INTERPOLATION(0,4,6)\"],\"MaxAlgorithmThreadCount\":1,\"Name\":\"high-density-qr-tpl\",\"ScaleDownThreshold\":10000,\"Timeout\":5000},\"Version\":\"3.0\"}";
// Apply the template string to the reader.
reader.initRuntimeSettingsWithString(jsonPara, EnumConflictMode.CM_OVERWRITE);
TextResult[] result = reader.decodeFile("YOUR-IMAGE-FILE-PATH");

NSError* err = nil;
NSString* jsonPara = @"{\"ImageParameter\":{\"BarcodeComplementModes\":[\"BCM_SKIP\"],\"DeblurModes\":[{\"Mode\":\"DM_SHARPENING\"},{\"Mode\":\"DM_GRAY_EQUALIZATION\"}],\"ExpectedBarcodesCount\":1,\"LocalizationModes\":[\"LM_CONNECTED_BLOCKS\"],\"ScaleUpModes\":[\"SUM_LINEAR_INTERPOLATION(0,4,6)\"],\"MaxAlgorithmThreadCount\":1,\"Name\":\"high-density-qr-tpl\",\"ScaleDownThreshold\":10000,\"Timeout\":5000},\"Version\":\"3.0\"}";
// Apply the template string to the reader.
[reader initRuntimeSettingsWithString:jsonPara conflictMode:EnumConflictModeOverwrite error:&err];
NSArray<iTextResult*>* result = [reader decodeFileWithName:"YOUR-IMAGE-FILE-PATH" error:&err];

let jsonPara = "{\"ImageParameter\":{\"BarcodeComplementModes\":[\"BCM_SKIP\"],\"DeblurModes\":[{\"Mode\":\"DM_SHARPENING\"},{\"Mode\":\"DM_GRAY_EQUALIZATION\"}],\"ExpectedBarcodesCount\":1,\"LocalizationModes\":[\"LM_CONNECTED_BLOCKS\"],\"ScaleUpModes\":[\"SUM_LINEAR_INTERPOLATION(0,4,6)\"],\"MaxAlgorithmThreadCount\":1,\"Name\":\"high-density-qr-tpl\",\"ScaleDownThreshold\":10000,\"Timeout\":5000},\"Version\":\"3.0\"}"
// Apply the template string to the reader.
try? reader.initRuntimeSettingsWithString(jsonPara,conflictMode:EnumConflictMode.overwrite)
let result = try? reader.decodeFileWithName("YOUR-IMAGE-FILE-PATH")

error = BarcodeReader.init_license("YOUR-LICENSE-KEY")
if error[0] != EnumErrorCode.DBR_OK:
    print(error[1])
dbr = BarcodeReader()
dbr.init_runtime_settings_with_string('{"Version":"3.0", "ImageParameter":{"Name":"high-density-qr-tpl","DeblurModes":[{"Mode":"DM_SHARPENING"},{"Mode":"DM_GRAY_EQUALIZATION"}],"ExpectedBarcodesCount":1,"LocalizationModes":[{"Mode":"LM_CONNECTED_BLOCKS"}],"ScaleUpModes": [{"Mode": "SUM_LINEAR_INTERPOLATION","AcuteAngleWithXThreshold": 0,"ModuleSizeThreshold": 4,"TargetModuleSize": 6}],"ScaleDownThreshold":10000,"Timeout":5000}}')
text_results = dbr.decode_file("YOUR-IMAGE-FILE-PATH")
# Add further process

BarcodeReader.initLicense("YOUR-LICENSE-KEY");
BarcodeReader reader = new BarcodeReader();
reader.initRuntimeSettingsWithString("{\"Version\":\"3.0\", \"ImageParameter\":{\"Name\":\"high-density-qr-tpl\",\"DeblurModes\":[{\"Mode\":\"DM_SHARPENING\"},{\"Mode\":\"DM_GRAY_EQUALIZATION\"}],\"ExpectedBarcodesCount\":1,\"LocalizationModes\":[{\"Mode\":\"LM_CONNECTED_BLOCKS\"}],\"ScaleUpModes\": [{\"Mode\": \"SUM_LINEAR_INTERPOLATION\",\"AcuteAngleWithXThreshold\": 0,\"ModuleSizeThreshold\": 4,\"TargetModuleSize\": 6}],\"ScaleDownThreshold\":10000,\"Timeout\":5000}}}", EnumConflictMode.CM_OVERWRITE);
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();
reader.InitRuntimeSettingsWithString("{\"Version\":\"3.0\", \"ImageParameter\":{\"Name\":\"high-density-qr-tpl\",\"DeblurModes\":[{\"Mode\":\"DM_SHARPENING\"},{\"Mode\":\"DM_GRAY_EQUALIZATION\"}],\"ExpectedBarcodesCount\":1,\"LocalizationModes\":[{\"Mode\":\"LM_CONNECTED_BLOCKS\"}],\"ScaleUpModes\": [{\"Mode\": \"SUM_LINEAR_INTERPOLATION\",\"AcuteAngleWithXThreshold\": 0,\"ModuleSizeThreshold\": 4,\"TargetModuleSize\": 6}],\"ScaleDownThreshold\":10000,\"Timeout\":5000}}}", EnumConflictMode.CM_OVERWRITE, 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();
reader->InitRuntimeSettingsWithString("{\"Version\":\"3.0\", \"ImageParameter\":{\"Name\":\"high-density-qr-tpl\",\"DeblurModes\":[{\"Mode\":\"DM_SHARPENING\"},{\"Mode\":\"DM_GRAY_EQUALIZATION\"}],\"ExpectedBarcodesCount\":1,\"LocalizationModes\":[{\"Mode\":\"LM_CONNECTED_BLOCKS\"}],\"ScaleUpModes\": [{\"Mode\": \"SUM_LINEAR_INTERPOLATION\",\"AcuteAngleWithXThreshold\": 0,\"ModuleSizeThreshold\": 4,\"TargetModuleSize\": 6}],\"ScaleDownThreshold\":10000,\"Timeout\":5000}}}", CM_OVERWRITE, errorBuf, 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();
DBR_InitRuntimeSettingsWithString(barcodeReader, "{\"Version\":\"3.0\", \"ImageParameter\":{\"Name\":\"high-density-qr-tpl\",\"DeblurModes\":[{\"Mode\":\"DM_SHARPENING\"},{\"Mode\":\"DM_GRAY_EQUALIZATION\"}],\"ExpectedBarcodesCount\":1,\"LocalizationModes\":[{\"Mode\":\"LM_CONNECTED_BLOCKS\"}],\"ScaleUpModes\": [{\"Mode\": \"SUM_LINEAR_INTERPOLATION\",\"AcuteAngleWithXThreshold\": 0,\"ModuleSizeThreshold\": 4,\"TargetModuleSize\": 6}],\"ScaleDownThreshold\":10000,\"Timeout\":5000}}}", CM_OVERWRITE, errorBuf, 512);
DBR_DecodeFile(barcodeReader, "YOUR-IMAGE-FILE-PATH", ""); // Start decoding
// Add further process