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How to Read License Plates using IronOCR

Curtis Chau

Updated:June 22, 2025

When managing a large volume of vehicle images, manually reading license plates is time-consuming and prone to human error. Automating this process with a tool like IronOCR provides a more efficient, accurate solution. IronOCR's ReadLicensePlate method can programmatically extract license plate numbers from images, saving considerable time while improving data accuracy.

In this guide, we’ll demonstrate how to use IronOCR for license plate recognition, walking through examples and customizable configurations that make the process seamless. By leveraging these methods, developers can automate license plate reading, making tasks like parking management, toll collection, or security surveillance more efficient.

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First Step:

Start for Free

To use this function, you must also install the IronOcr.Extension.AdvancedScan package.

Read License Plate Example

To read a license plate in IronOCR, we have to apply the following steps:

• We utilize the ReadLicensePlate method, which takes an OcrInput as a parameter for the input. This method is more optimized for license plates precisely than the library's standard Read counterpart.
• Optionally, we can configure IronOCR to whitelist specific characters only that can exist in a license plate, to speed up the license plate number processing.

License Plate

Code

:path=/static-assets/ocr/content-code-examples/how-to/read-license-plate-read-license-plate.cs

using IronOcr;
using System;

var ocr = new IronTesseract();
ocr.Configuration.WhiteListCharacters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_";

using var inputLicensePlate = new OcrInput();
inputLicensePlate.LoadImage("plate.jpeg");

// Read license plate
OcrLicensePlateResult result = ocr.ReadLicensePlate(inputLicensePlate);

// Retrieve license plate number and confidence value
string output = $"{result.Text}\nResult Confidence: {result.Confidence}";

Console.WriteLine(output);

Imports Microsoft.VisualBasic
Imports IronOcr
Imports System

Private ocr = New IronTesseract()
ocr.Configuration.WhiteListCharacters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_"

Dim inputLicensePlate = New OcrInput()
inputLicensePlate.LoadImage("plate.jpeg")

' Read license plate
Dim result As OcrLicensePlateResult = ocr.ReadLicensePlate(inputLicensePlate)

' Retrieve license plate number and confidence value
Dim output As String = $"{result.Text}" & vbLf & "Result Confidence: {result.Confidence}"

Console.WriteLine(output)

Output

The code demonstrates how to import an image as an OcrInput and use it with the ReadLicensePlate method to extract the text from the license plate. The output shows the extracted text that matches the license plate shown in the input image, along with a confidence level indicating the accuracy of the OCR.

Text: The extracted text from OCR Input.

Confidence: A "double" property that indicates the statistical accuracy confidence of an average of every character, with one being the highest and 0 being the lowest.

License Plate From a Car Image

The method also works well with images containing a car with a license plate. The code is the exact same as the one above, with the input image changed. You can also extract the pixel coordinates of the area where the license plate is situated in the image.

Example Input

:path=/static-assets/ocr/content-code-examples/how-to/read-license-plate-read-from-car.cs

using IronOcr;
using IronSoftware.Drawing;
using System;

var ocr = new IronTesseract();
using var inputLicensePlate = new OcrInput();
inputLicensePlate.LoadImage("car_license.jpg");

// Read license plate
OcrLicensePlateResult result = ocr.ReadLicensePlate(inputLicensePlate);

// Retrieve license plate coordinates
RectangleF rectangle = result.Licenseplate;

// Write license plate value and coordinates in a string
string output = $"License Plate Number:\n{result.Text}\n\n"
              + $"License Plate Area_\n"
              + $"Starting X: {rectangle.X}\n"
              + $"Starting Y: {rectangle.Y}\n"
              + $"Width: {rectangle.Width}\n"
              + $"Height: {rectangle.Height}";

Console.WriteLine(output);

Imports Microsoft.VisualBasic
Imports IronOcr
Imports IronSoftware.Drawing
Imports System

Private ocr = New IronTesseract()
Private inputLicensePlate = New OcrInput()
inputLicensePlate.LoadImage("car_license.jpg")

' Read license plate
Dim result As OcrLicensePlateResult = ocr.ReadLicensePlate(inputLicensePlate)

' Retrieve license plate coordinates
Dim rectangle As RectangleF = result.Licenseplate

' Write license plate value and coordinates in a string
Dim output As String = $"License Plate Number:" & vbLf & "{result.Text}" & vbLf & vbLf & $"License Plate Area_" & vbLf & $"Starting X: {rectangle.X}" & vbLf & $"Starting Y: {rectangle.Y}" & vbLf & $"Width: {rectangle.Width}" & vbLf & $"Height: {rectangle.Height}"

Console.WriteLine(output)

Output

The example shows how the ReadLicensePlate method can be applied to an image of a car. The method will also return the rectangle coordinates of where the license plate is situated in the image.

This method is optimized to find single license plates only and is capable of searching for them in stock images.

Curtis Chau

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Technical Writer

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.

Beyond development, Curtis has a strong interest in the Internet of Things (IoT), exploring innovative ways to integrate hardware and software. In his free time, he enjoys gaming and building Discord bots, combining his love for technology with creativity.

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