FAQ

Frequently asked questions

My scanner is not detected (Windows)

On Windows, gImageReader uses TWAIN for communicating with scanners. gImageReader implements the TWAIN 2.2 specification, and supports both TWAIN 1.x and TWAIN 2.x data sources (drivers). Typically, there are two main causes which leads to a scanner not being recognized under Windows:

1. There is no TWAIN driver installed for the scanner: TWAIN drivers should be installed in C:\WINDOWS\twain_32 or C:\WINDOWS\twain_64. Check these locations whether there are any drivers related to your scanner, resp. check the manufacturers website whether they offer a TWAIN driver for download.
2. TWAIN driver architecture mismatch: If your scanner ships a 32bit TWAIN driver (i.e. installed in C:\WINDOWS\twain_32), then you'll need to use the 32bit (aka i686) version of gImageReader. If your scanner ships a 64bit TWAIN driver, you'll need to use the 64bit (aka x86_64) version of gImageReader.

The application crashes on subsequent scans (Linux)

There is a bug in certain SANE scanner drivers which causes gImageReader to crash when a second page is scanned. This problem has been reported upstream and a patch suggested. If you are affected by this issue, you'll need to either recompile sane-backends from source with the patch applied or ask your distribution to include this patch.

Where are the tesseract language definitions and spelling dictionaries stored?

You can see the paths in the gImageReader preferences dialog. In particular, the paths depend on whether you have selected system-wide or user-local paths in the preferences dialog.

Automatic download of spelling dictionaries / (un)installation of tesseract language definitions fails

• On Windows, if you don't have writing permissions to the location where gImageReader is installed, you can selected user-local paths in the preferences dialog. gImageReader will then store these files below your home folder.
• On Linux, (un)installation to/from system-wide folders only works if you have PackageKit installed. Alternatively, you may manage the corresponding packages directly via the distribution's package management tools. Or you can select user-local paths in the preferences dialog, and gImageReader will store the files below your home folder, without using any package management tool.

Only a limited number of image formats can be opened (Linux)

The available image formats depend on which Qt image format plugins are installed on the system. If you are using gImageReader compiled against Qt5, make sure the Qt5 image plugins package is installed (on Debian/Ubuntu it's called qt5-image-formats-plugins, on Fedora qt5-qtimageformats).

Certain characters are incorrectly encoded in the text output

If you are using the Qt5 interface of gImageReader, you can choose in the program options whether the text output is encoded using system encoding or UTF-8. Default is system encoding.

Do I need to install tesseract separately? (Windows)

No, the gImageReader Windows installer bundles the necessary tesseract files. If you want to install tesseract separately for other uses you can clearly do so, but it has no effect on gImageReader.

How do I install tesseract language definitions?

The easiest way is by using the integrated tessdata manager: from the language selection menu, select Manage languages... and select the languages you need. You can also install the languages manually, as described in the manual (Help entry in the application menu).

What is the difference between tesseract language definitions and spelling dictionaries?

The tesseract language definition is used by tesseract (the OCR engine) for the actual recognition. The spelling dictionary is used for spell-checking the recognized text in the output pane.