OCR

This guide helps you resolve common issues when using OCR (Optical Character Recognition) in VNTranslator.

Screen Capture Test

Verify that screen capture is working correctly:

Click Pre-processing in the Side Toolbar
Enable Adjustments and Greyscale
Click Capture to take a test screenshot
Adjust the Threshold value until the text appears clearly in black and white

What to Expect:

If the capture works correctly, the preview will show the image in black and white

Display and Monitor Issues

Supported Monitor Configurations

VNTranslator OCR supports various monitor setups:

OCR version 1.x: Single monitor only
OCR version 2.x: Multi-monitor support (horizontal arrangement / X-axis)
OCR version 3.x: ~~Multi-monitor support (horizontal and vertical arrangement / X & Y-axis)~~

Display Scaling Issue

Problem: The OCR Capture Area doesn't align with the actual text position on screen, or captured images appear cropped or misaligned.

Cause: Windows display scaling affects what you see on screen, but OCR captures the actual pixel coordinates without scaling.

Solution:

VNTranslator Pro supports display scaling. Configure it in the app settings:

Open VNTranslator Settings.
Go to App Settings -> Display -> Scale.
Select the appropriate scale setting that matches your Windows display scaling.
Relaunch VNTranslator.

Alternative solution:

If issues persist, you can change Windows display scaling to 100%:

Open Windows Settings
Go to System -> Display
Set Scale to 100% for the monitor where you're running your game
Relaunch VNTranslator

Note: VNTranslator Pro now supports display scaling through app settings, but using 100% Windows scaling can still provide the most consistent results.

Graphics Card Issue

List of Error Messages:

Error Code 11x
Screen capture failed
Display source not detected!

1. Update Graphics Drivers

Windows Update doesn't always provide the latest drivers. Download directly from your graphics card manufacturer:

NVIDIA drivers: http://www.nvidia.com/content/drivers/
AMD drivers: http://support.amd.com/en-us/download
Intel drivers: https://downloadcenter.intel.com/

2. Switch Between GPUs (Multi-GPU Systems)

If your computer has more than one graphics card, then Try to switch between Dedicated GPU & Integrated GPU.

NVIDIA Optimus: Go to NVIDIA Control Panel -> Manage 3D settings -> Program Settings
AMD Switchable: Go to AMD Radeon Settings -> Switchable Graphics

3. Disable capture/recording in GeForce Experience / AMD Radeon

Graphics card recording features can interfere with OCR screen capture.

GeForce Experience: Disable In-Game Overlay, Disable Dekstop Capture (Privacy control), Disable Instant Replay
AMD Radeon: Disable In-Game Overlay, Disable Record Dekstop, Disable Instant Replay, Disable In-Game Replay

4. Disable hardware acceleration

If other solutions don't work, try disabling hardware acceleration in VNTranslator.

Method 1: Via VNTranslator Settings: Go to Settings -> App Settings -> Advanced -> Hardware acceleration
Method 1: Via Command Line C:\Program Files\VNTranslator\VNTranslator.exe --disable-gpu C:\Program Files\VNTranslator\VNTranslator.exe --disable-gpu --force-cpu-draw

Screen Capture Error Occurs

List of Error Messages:

Error Code 10x
Image processing error
Undefined image
Screen capture failed
Application crashes when the Capture button is pressed
INVALID_ARGUMENT - Request must specify image and features

Solution 1: Run as Administrator

Right-click VNTranslator.exe
Select Run as administrator

Solution 2: Reinstall for All Users

Uninstall VNTranslator
Reinstall and choose Install for all users
Install to: C:\Program Files\VNTranslator

Solution 3: Install/Update Visual C++ Redistributable

Download both x86 and x64 versions from Microsoft: Visual C++ Redistributable Latest
Install both versions
Restart your computer

Solution 4: Change Display Source

Open VNTranslator Settings
Go to App Settings -> Display
Change Display Source to either Native or Windows
Relaunch VNTranslator

Solution 5: Run Display Test for Debugging

If the issue persists, use the built-in Display Test feature to help diagnose the problem

In the Launcher, Menubar -> Quick Actions -> Display Test
Wait a few seconds, the test will run automatically
Once completed, a folder named VNT_DISPLAY_TEST will be created on your Desktop

The VNT_DISPLAY_TEST folder contains the following:

A fullscreen capture image
A cropped capture image
A log file with diagnostic information

OCR Server Connection Issues

Problem: "Unable to connect to OCR Server" or the OCR process hangs for 15-60 seconds without responding.

Possible causes:

Insufficient RAM
Firewall blocking the connection
Tesseract OCR or Window OCR Server not responding

Solution 1: Run as Administrator

Right-click VNTranslator.exe
Select Run as administrator

Solution 2: Configure Windows Firewall

Open Windows Security -> Firewall & network protection
Click Allow an app through firewall
Click Change settings -> Allow another app
Browse to C:\Program Files\VNTranslator\VNTranslator.exe
Add VNTranslator and allow it on both Private and Public networks

Note: If you're using third-party firewall software (BitDefender, Norton, McAfee), add VNTranslator as an exception in that software.

Solution 3: Disable Tesseract Server

Open VNTranslator Settings
Go to OCR Settings
Disable Tesseract Server (this will use Tesseract Wrapper instead)

Tesseract is not installed

Solution:

Download Tesseract OCR from the official source
Install to: C:\Program Files\Tesseract-OCR
Make sure the installation path is exactly as shown above
Relaunch VNTranslator

Tesseract process exited with code 1 - Command failed: ???

Solutions 1: Reinstall Tesseract:

Uninstall Tesseract completely
Restart your computer
Download and reinstall Tesseract
Install to: C:\Program Files\Tesseract-OCR

Solution 2: Try a different Tesseract version

Download alternative versions from the Tesseract releases

Search for specific error

Search on Google or Stack Overflow for solutions specific to that error 🙃

TESSDATA_PREFIX is not set to your tessdata directory

Solution:

Open Command Prompt as administrator
type setx TESSDATA_PREFIX "C:\Program Files\Tesseract-OCR\tessdata", and then press Enter
Restart your computer

Err: Failed to init API, possibly an invalid tessdata path: ./

Solution:

Open Command Prompt as administrator
type setx TESSDATA_PREFIX "C:\Program Files\Tesseract-OCR\tessdata", and then press Enter
Restart your computer

Google Lens - Request failed with status code 303

Solution:

Restart your modem/router
Use a VPN
Or use a more stable offline OCR engine such as Fast OCR and ScreenAI OCR 😄

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