TWAIN
TWAIN is a standard software protocol and API (Applications Programming Interface) that controls communication between software applications and imaging devices such as scanners and digital cameras.
The TWAIN group was originally launched in 1992 by leading industry vendors who recognised a need for more communication between the image handling software and the scanning hardware. Today the TWAIN standard, including the specification, data source manager and sample code, are maintained by the TWAIN Working Group.
The TWAIN Working Group is a not-for-profit organisation which represents the imaging industry. TWAINs’ purpose is to provide and foster a universal public standard which links applications and image acquisition devices. The mission of the organisation is to continue to enhance the standard to accommodate future technologies. The latest released version of the TWAIN standard is 2.0 (November 2008).
TWAIN was designed to provide consistent, easy integration of image data between sophisticated input devices and software applications.
The hardware interface element of the TWAIN architecture is known as the Source or Data Source. A Source is a TWAIN entity whose purpose is to get data from a hardware device and provide it to a TWAIN-compliant application. A Source is typically written by the hardware vendor to control their peripheral device. These devices are usually hardware, such as scanners or cameras. The device may be locally connected or remotely accessed over a network.
TWAIN defines a standard software protocol and API (application programming interface) for communication between software applications and image acquisition devices (the source of the data).
The three key elements in TWAIN are:
Application software
An application must be designed or modified to use TWAIN. Typical applications include Batch Scanning and Document Management.
Source Manager software
This software manages the interactions between the application and the Source. This code is provided in the TWAIN Developer’s Toolkit and should be shipped for free with each TWAIN application and Source.
Source software
This software controls the image acquisition device and is written by the device developer to comply with TWAIN specifications. Traditional device drivers are now included with the Source software and do not need to be shipped by applications.
To acquire an image using the TWAIN protocol, the user first chooses “Select Source” from the Application’s menu. “Select Source” identifies the source device from which the image will be acquired, and is only accessed by the user when it’s necessary to switch between connected devices. “Select Source” invokes the Source Manager and a selection dialog box appears. Once the source is selected, the user chooses “Acquire” (or “Scan”) to initiate the image acquisition process. “Acquire” brings up the Source Manager and, after capabilities negotiation, control is passed to the Source.
Contrary to popular opinion Twain is not an acronym for “Technology Without An Interesting Name.”