# 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.

<div align="center">
   <p><img src="assets/read-dense-barcodes/dense-qr-code.jpg" alt="High-density QR Code" width="80%" /></p>
   <p>Figure 1 – High-density QR Code</p>
</div>

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

## Example

Below is an example illustrating how to configure the parameters to read density QR Codes.

* Update parameters in your JSON template

    ```json
    {
        "CaptureVisionTemplates": [
            {
                "Name": "CV_0",
                "ImageROIProcessingNameArray": ["TA_0" ],
                "Timeout":5000
            }       
        ],
        "TargetROIDefOptions" : [
            {
                "Name": "TA_0",
                "TaskSettingNameArray": [ "BR_0" ]
            }
        ],
        "BarcodeReaderTaskSettingOptions": [
            {
                "Name" : "BR_0",
                "BarcodeFormatIds" : ["BF_QR_CODE"],
                "ExpectedBarcodesCount" : 1,
                "SectionArray": [
                    {
                        "Section": "ST_REGION_PREDETECTION",
                        "ImageParameterName": "IP_0"
                    },
                    {
                        "Section": "ST_BARCODE_LOCALIZATION",
                        "ImageParameterName": "IP_0",
                        "StageArray": [
                            {
                                "Stage": "SST_LOCALIZE_CANDIDATE_BARCODES",
                                "LocalizationModes":[
                                    {
                                        "Mode": "LM_CONNECTED_BLOCKS"
                                    }
                                ]
                            }
                        ]
                    },
                    {
                        "Section": "ST_BARCODE_DECODING",
                        "ImageParameterName": "IP_0",
                        "StageArray": [
                            {
                                "Stage": "SST_SCALE_BARCODE_IMAGE",
                                "BarcodeScaleModes": [
                                    {
                                        "Mode": "BSM_LINEAR_INTERPOLATION", 
                                        "ModuleSizeThreshold": 4,
                                        "TargetModuleSize": 6,
                                        "AcuteAngleWithXThreshold": 0
                                    },
                                ]
                            },
                            {
                                "Stage": "SST_DECODE_BARCODES",
                                "DeblurModes":[
                                    {
                                        "Mode": "DM_SHARPENING"
                                    },
                                    {
                                        "Mode": "DM_GRAY_EQUALIZATION"
                                    }
                                ]
                            }
                        ]
                    }
                ]
            }
        ],
        "ImageParameterOptions": [
            {
                "Name": "IP_0",
                "ApplicableStages":[
                    { 
                        "Stage": "SST_SCALE_IMAGE",
                        "ImageScaleSetting": {
                            "ScaleType": "ST_SCALE_DOWN",
                            "ReferenceEdge": "RE_SHORTER_EDGE",
                            "EdgeLengthThreshold": 10000
                        }
                    }
            }
        ]
    }
    ```

* Apply the above settings following the article [Use Templates for Configuring Parameters](https://www.dynamsoft.com/barcode-reader/docs/core/programming/features/use-runtimesettings-or-templates.md#json-template).