How to Read Barcodes from Large Images

In some cases, the captured image is very large, so Dynamsoft Barcode Reader (DBR) may require more memory and take longer to read the barcode. To speed up the barcode localization process and reduce memory overhead, you can configure the ScaleDownThreshold parameter to shrink the image size. If the shorter side length of the image is larger than ScaleDownThreshold, the library will shrink the image (50% on each dimension) until the shorter side is less than the threshold.

Note:

Don’t worry about the location of the barcodes, as DBR will still return their coordinates in the original image.

Sample Code

Below is an example illustrating how to configure the parameter ScaleDownThreshold.

update parameter ScaleDownThreshold in your JSON template

  {
      "CaptureVisionTemplates": [
          {
              "Name": "CV_0",
              "ImageROIProcessingNameArray": ["TA_0" ]
          }       
      ],
      "TargetROIDefOptions" : [
          {
              "Name": "TA_0",
              "TaskSettingNameArray": [ "BR_0" ]
          }
      ],
      "BarcodeReaderTaskSettingOptions": [
          {
              "Name" : "BR_0",
              "SectionImageParameterArray": [
                  {
                      "Section": "ST_REGION_PREDETECTION",
                      "ImageParameterName": "IP_0"
                  },
                  {
                      "Section": "ST_BARCODE_LOCALIZATION",
                      "ImageParameterName": "IP_0"
                  },
                  {
                      "Section": "ST_BARCODE_DECODING",
                      "ImageParameterName": "IP_0"
                  }
              ]
          }
      ],
      "ImageParameterOptions": [
          {
              "Name": "IP_0",
              "ScaleDownThreshold": 1600
          }
      ]
  }

apply settings by calling method InitSettingsFromFile

JavaScript
C++
Android
Objective-C
Swift

// `router` is an instance of `CaptureVisionRouter`.
// In the JS edition, the method name we use for initialization is different.
router.initSettings("PATH-TO-YOUR-SETTING")

char szErrorMsg[256] = {0};
CCaptureVisionRouter* cvr = new CCaptureVisionRouter;
cvr->InitSettingsFromFile("PATH-TO-YOUR-SETTING-FILE", szErrorMsg, 256);
// more process here

try {
   // `cvr` is an instance of `CaptureVisionRouter`.
   cvr.initSettingsFromFile("PATH-TO-YOUR-SETTING-FILE");
} catch (CaptureVisionRouterException e) {
   e.printStackTrace();
}

NSError *error;
// `cvr` is an instance of `DSCaptureVisionRouter`.
[self.cvr initSettingsFromFile:@"PATH-TO-YOUR-SETTING-FILE" error:&error];

do{
   //`cvr` is an instance of `CaptureVisionRouter`.
   try cvr.initSettingsFromFile("PATH-TO-YOUR-SETTING-FILE")
}catch{
   // Add code to do when error occurs.
}