How to Read Barcodes with Imbalanced Colour

As we all know, any color is composed of red, blue and green (RGB). If the image is a colour image, Dynamsoft Barcode Reader (DBR) will convert it to grayscale first for further processing.

Gray = Red*RedChannelWeight + Green*GreenChannelWeight + Blue*BlueChannelWeight

The default weights in DBR are suitable for most cases. However, some color images may produce poor grayscale images based on the default weights. For example, the image below is a color image with imbalanced colour.

barcode colour image

Figure 1 – Sample barcode colour image

The image below shows the grayscale image converted by DBR using the default channel weights setting.

barcode gray image using default

Figure 2 – Sample barcode gray image using default mode

The image below shows the grayscale image converted by DBR using only red channel.

barcode gray image using red

Figure 3 – Sample barcode gray image using only red channel

As we can see, the gray image converted using only red channel is much better than the default one. Now we will demonstrate how to configure the parameter ColourConversionModes to adjust the colour channel weights used for converting a colour image to a grayscale image.

Particular Parameter Required

DBR provides a parameter ColourConversionModes that allows you to control the conversion of a color image to grayscale.

Sample Code

Below is an example illustrating how to configure the parameter ColourConversionModes to use only red channel.

update parameter ColourConversionModes 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",
              "ColourConversionModes": [
                  {
                      "Mode": "CICM_GENERAL",
                      "RedChannelWeight": 1000,
                      "GreenChannelWeight": 0,
                      "BlueChannelWeight": 0
                  }
              ]
          }
      ]
  }

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.
}