---
layout: default-layout
needAutoGenerateSidebar: true
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title: Dynamic Web TWAIN SDK Features - OCR
keywords: Dynamic Web TWAIN, Documentation, OCR
breadcrumbText: OCR
description: Dynamic Web TWAIN SDK Documentation OCR Page
---
# OCR
Dynamic Web TWAIN provides an OCR add-on to extract text from scanned images. It utilizes the latest deep learning techniques and delivers high accuracy. All processing occurs locally on end-user devices, with no data uploaded to cloud servers.
Read on to learn about how to use it.
## Requirements
* Windows 10 versions >= 1809 and all versions of Windows 11
* A license with the OCR module ([contact support to get a 30-day trial license](mailto:support@dynamsoft.com))
* [DynamicWebTWAINOCRResources.zip](https://download2.dynamsoft.com/dwt/DynamicWebTWAINOCRResources.zip)
## Online Demo
You can visit the [online demo](https://demo.dynamsoft.com/Samples/dwt/OCR/index.html) ([source code](https://download2.dynamsoft.com/Samples/DWT/Scan-Documents-and-Do-OCR.zip)) to try it.
## How to Use
### Step One - Install the OCR Package
Download [DynamicWebTWAINOCRResources.zip](https://download2.dynamsoft.com/dwt/DynamicWebTWAINOCRResources.zip), unzip it and run `Install.cmd` inside the `DynamicWebTWAINOCRPack.zip` file as admin to install the OCR package.
It will copy an `ocr` folder to Dynamic Web TWAIN Service's [installation folder](/_articles/extended-usage/dynamsoft-service-configuration.md#installation-folder). The `ocr` folder contains the runtime and model files that are required to perform on-device OCR.
> [!NOTE]
> * You need to [install Dynamic Web TWAIN Service](/_articles/extended-usage/dynamsoft-service-configuration.md#installation-of-dynamic-web-twain-service) beforehand.
> * Since only Windows is supported for now, you have to do this on a Windows client for testing.
### Step Two - Write a Basic Document Scanning Page
Create an HTML file with the following content. It can scan documents from scanners as well as loading local images.
```html
Dynamic Web TWAIN - OCR Demo
```
PS: You can find where the resources files are in this [FAQ](/_articles/faq/what-are-the-resources-files.md).
### Step Three - Include the Add-on
Reference the add-on's JavaScript with the following code. You can find the file in `DynamicWebTWAINOCRResources.zip`.
> If you are using the [npm package](https://www.npmjs.com/package/dwt), the OCR is already included in the main JavaScript file (`dynamsoft.webtwain.min.js` or `dynamsoft.webtwain.min.mjs`), which means you can skip this step.
```html
```
Then, you can run the following to check if it is installed correctly:
```js
async function CheckIsOCRInstalled(){
try {
let info = await DWTObject.Addon.OCRKit.GetInstalledOCRInfo();
console.log(info);
if (info.version) {
return true;
}
} catch (error) {
alert(error.message);
return false;
}
alert("OCR Add-on is not installed. Please install it to use OCR features.");
return false;
}
```
APIs used:
[`GetInstalledOCRInfo()`](/_articles/info/api/Addon_OCR.md#getinstalledocrinfo)
### Step Four - Detect Page Orientation
This is an optional step. If the scanned document is rotated, we can detect its orientation and rotate it.
```js
async function CorrectOrientationForOne(index){
let result = await DWTObject.Addon.OCRKit.DetectPageOrientation(index);
if (result.angle != 0) {
DWTObject.Rotate(index,-result.angle,true);
}
}
```
APIs used:
- [`DetectPageOrientation()`](/_articles/info/api/Addon_OCR.md#detectpageorientation)
- [`Rotate()`](/_articles/info/api/WebTwain_Edit.md#rotate)
### Step Five - Recognize Text
Recognize the text in one image and print it in a `pre` element.
```html
```
APIs used:
[`Recognize()`](/_articles/info/api/Addon_OCR.md#recognize)
### Step Six - Save as PDF
After recognition, we can save the OCR results and images as a PDF file. It will add an invisible text layer above the original content so that the text becomes selectable and searchable.
```js
let indicesOfAll = DWTObject.SelectAllImages();
await DWTObject.Addon.OCRKit.SaveToPath(indicesOfAll,Dynamsoft.DWT.EnumDWT_OCRKitOutputFormat.PDF_WITH_EXTRA_TEXTLAYER,"output.pdf");
```
APIs used:
[`SaveToPath()`](/_articles/info/api/Addon_OCR.md#savetopath)
### Step Seven - Review the Complete Code
Here is the complete code of the demo.
```html
Dynamic Web TWAIN - OCR Demo
```
This complete code is different from the [online demo](#online-demo)'s code, which supports regional OCR. You can find the code for the online demo [here](https://download2.dynamsoft.com/Samples/DWT/Scan-Documents-and-Do-OCR.zip).
## FAQ
### What Languages are Supported?
The OCR add-on supports multiple languages including English, French, Spanish, German, Italian, and Portuguese.
Contact [support](mailto:support@dynamsoft.com) if you need to OCR documents in other languages.
### What are the Hardware Requirements?
The OCR add-on requires a 64-bit operating system and at least 4GB of RAM for optimal performance.
### Can I Limit the Region for OCR?
Yes. You can specify which regions for OCR using the `rects` option of the [`recognize()`](/_articles/info/api/Addon_OCR.md#recognize) function.
### Will My Document be Uploaded to a Remote Server?
No. The OCR process happens locally on your machine. No data is sent to any remote servers. Also, we do not collect data for training AI.
### What is Searchable PDF?
A searchable PDF is a type of PDF file where the text content is recognized by a computer. This means you can use the Find function (usually Ctrl+F or Cmd+F) to search for specific words or phrases within the document, just like you would on a webpage or in a Word document.
The OCR add-on supports two kinds of searchable PDF output.
* Plain-text PDF, which will only keep a text layer of the OCRed text for each page.
* Extra-text-layer PDF, which will add an extra invisible text layer of the OCRed text above each page.
### What are OCR Basic and OCR Pro?
OCR Basic and OCR Pro are previous OCR add-ons, which are deprecated in v16.2. But they are still usable in the latest version.
To differentiate from previous versions, the new OCR added since v19.3 uses `OCRKit` as the namespace.
### Why I Cannot Load Saved PDF Files
The searchable PDF saved has a text layer. You need to use [PDF Rasterizer](/_articles/info/api/Addon_PDF.md) to load it. A PDF Rasterizer license is required.