# Barcode Not Recognized
Sometimes, despite appearing visually correct, barcodes may not be recognized during scanning.
## Possible Causes
1. **Unsupported Barcode Encoding:** While IronBarcode supports various barcode formats, it may not recognize certain encodings.
2. **Low Resolution:** A barcode image with low resolution or noisy image quality reduces the chances of successful reading.
3. **Barcode Positioning:** Barcodes positioned near the edges of documents or images might not be detected. Barcodes that are partly cut off may also not be read properly.
4. **Imperfect Barcode Image:** Issues such as noisy backgrounds, glare, blurriness, or low lighting can hinder barcode readability.
## Solutions
Fortunately, IronBarcode offers solutions to address these issues. Follow the troubleshooting steps below:
### 1. **Specify Barcode Encoding**
If you know the specific barcode encoding, set the [`ExpectBarcodeTypes`](/csharp/barcode/object-reference/api/IronBarCode.BarcodeReaderOptions.html#IronBarCode_BarcodeReaderOptions_ExpectBarcodeTypes) property in the [`BarcodeReaderOptions`](/csharp/barcode/object-reference/api/IronBarCode.BarcodeReaderOptions.html) class. This improves the chance the barcodes in the image will be detected and read.
[[i:(Not all encodings are supported. Check the [Supported Barcode Formats](/csharp/barcode/get-started/supported-barcode-formats/) article for more information.)]]
### 2. **Apply Image Correction Filters**
IronBarcode includes filters that help correct low-resolution or imperfect images for better barcode reading.
Learn more in the [Image Correction](/csharp/barcode/how-to/image-correction/) article.
### 3. **Specify Barcode Location**
For barcodes located at the edges of images or documents, specifying the barcode location can improve detection. This also enhances performance by reducing the scanning area. Use the `IronSoftware.Drawing.Rectangle` object in the `CropArea` property of the `BarcodeReaderOptions` class. Learn how in the [Crop Region Guide](/csharp/barcode/how-to/set-crop-region/).
### 4. **File Conversion**
Converting PDF documents to uncompressed image formats like TIFF or PNG can help in making undetectable barcodes readable. Similarly, converting pixelated JPG files can improve read quality.
### 5. **Increase DPI**
For PDF documents, increasing DPI can sharpen barcodes and enhance readability. Set the DPI property in the `PdfBarcodeReaderOptions` class.
[[i:(Increasing DPI may affect the read performance. Be sure to find the ideal setting that can balance the barcode readability without sacrificing too much performance)]]
## Helpful Articles
- [How to Read Barcodes from Image Files (JPEG, PNG, GIF, TIFF, SVG, BMP)](/csharp/barcode/how-to/read-barcodes-from-images/)
- [How to Read Barcodes from PDF Documents](/csharp/barcode/how-to/read-barcodes-from-pdf/)
If you need further assistance, submit an [Engineering Request](/csharp/barcode/troubleshooting/engineering-request-bc/).
Sometimes, despite appearing visually correct, barcodes may not be recognized during scanning.
Possible Causes
Unsupported Barcode Encoding: While IronBarcode supports various barcode formats, it may not recognize certain encodings.
Low Resolution: A barcode image with low resolution or noisy image quality reduces the chances of successful reading.
Barcode Positioning: Barcodes positioned near the edges of documents or images might not be detected. Barcodes that are partly cut off may also not be read properly.
Imperfect Barcode Image: Issues such as noisy backgrounds, glare, blurriness, or low lighting can hinder barcode readability.
Solutions
Fortunately, IronBarcode offers solutions to address these issues. Follow the troubleshooting steps below:
1. Specify Barcode Encoding
If you know the specific barcode encoding, set the ExpectBarcodeTypes property in the BarcodeReaderOptions class. This improves the chance the barcodes in the image will be detected and read.
Please note: Not all encodings are supported. Check the Supported Barcode Formats article for more information.
2. Apply Image Correction Filters
IronBarcode includes filters that help correct low-resolution or imperfect images for better barcode reading.
Learn more in the Image Correction article.
3. Specify Barcode Location
For barcodes located at the edges of images or documents, specifying the barcode location can improve detection. This also enhances performance by reducing the scanning area. Use the IronSoftware.Drawing.Rectangle object in the CropArea property of the BarcodeReaderOptions class. Learn how in the Crop Region Guide.
4. File Conversion
Converting PDF documents to uncompressed image formats like TIFF or PNG can help in making undetectable barcodes readable. Similarly, converting pixelated JPG files can improve read quality.
5. Increase DPI
For PDF documents, increasing DPI can sharpen barcodes and enhance readability. Set the DPI property in the PdfBarcodeReaderOptions class.
Please note: Increasing DPI may affect the read performance. Be sure to find the ideal setting that can balance the barcode readability without sacrificing too much performance
Curtis Chau holds a Bachelor’s degree in Computer Science (Carleton University) and specializes in front-end development with expertise in Node.js, TypeScript, JavaScript, and React. Passionate about crafting intuitive and aesthetically pleasing user interfaces, Curtis enjoys working with modern frameworks and creating well-structured, visually appealing manuals.
