ZT <windows Image Acquisition (WIA) > from MSDN

Windows Image Acquisition (WIA)

Windows Image Acquisition (WIA) is the still Image acquisition platform in the Windows family of operating systems Startin G with Windows Millennium Edition (Windows Me) and Windows XP.

• Introduction
• Benefits of Windows Image Acquisition 2.0
  • For application writers
  • For Device manufactures
  • For Scanner Users
• Development of Windows Image acquisition
• Overview of Windows Image acquisition
• Facts about Windows Image Acquisition 2.0
• Developer Audience
• Run-time Requirements
• WIA Topics

Introduction

The WIA platform enables Imaging/graphics applications to interact with imaging hardware and standardizes the interaction Between different applications and scanners. This allows those different applications to talk to and interact with those different scanners without requiring the appli cation writers and scanner manufactures to customize their application or drivers for each application-device combination.

Benefits of Windows Image Acquisition 2.0

WIA provides benefits to application developers, device manufacturers, and scanner users who need to interact with imaging Hardware.

For application writers

• Windows runs a certification process for WIA drivers so WIA applications is guaranteed to being base-level compatible with a ll wia-based scanners.
• WIA drivers is loaded in the WIA service process, thus providing a more stable driver environment.
• Applications can initiated from the Scanner Scan button via push events supported by the WIA subsystem.
• The WIA includes a default segmentation filter, all drivers can take advantage of; This is, applications do not has to write code for multi-region scanning for purposes such as separating out a large num ber of photos spread over a flatbed scanner.

For Device manufactures

• WIA Driver certification process helps driver developers in establishing this their driver is wia-compliant.
• WIA drivers can take advantage of a built-in segmentation filter, image processing filter and error handler, if they choos E to doing so.
• Wia-based scanners work right out of the box on Windows with Windows scanning applications such as Windows Fax and Scan an D Paint.
• WIA drivers offer better integration with Windows such as the full device experience.
• Windows Vista release includes a WSD-WIA class driver that enables all devices compliant with Web Services for Scanner (WS -scan) protocol to work with WIA applications without any additional driver or software.

For Scanner Users

• Wia-based scanners can be used from Windows applications such Windows Fax and Scan and Paint without the need for any Addi tional software.
• wia-based applications and scanners can also take advantage of WIA add-ons such as the segmentation filter which enables S Uch features as processing a number of pictures on the scanner and scanning them all to individual files without user inte Rvention.
• Wia-based devices offers a much better integration with other Windows features such as the Device Stage feature for Window S 7.
• WIA provides a more robust, stable and reliable scanning experience by isolating the driver and the application.

Development of Windows Image acquisition

The imaging architecture in Windows $ and Windows or later consisted of a low-level hardware abstraction, still IMAG E Architecture (STI), and a high-level set of APIs known as TWAIN. In Windows XP and Windows Me WIA is introduced. WIA is a imaging architecture that builds on STI and does not require TWAIN, although Twain is still supported alongside WIA.

WIA 1.0 is introduced in Windows Me and Windows XP and supports scanners, digital cameras and digital video equipment. WIA 2.0 is released with Windows Vista. WIA 2.0 is targeted towards scanners if continues to offer support for legacy WIA 1.0 applications and devices through a WIA 1.0 to WIA 2.0 compatibility layer provided by the WIA service. However, video content support is removed from WIA for Windows Vista. We recommend Windows portable Devices (WPD) API for digital cameras and digital video equipment on the future. WIA 1.0 as well as STI TWAIN drivers is still supported directly on Windows Vista and Windows 7 alongside native WIA 2.0 Device drivers and imaging applications.

Overview of Windows Image acquisition

WIA provides a framework, allows a device to present it unique capabilities to the operating system and allows Imagin G applications to invoke those unique capabilities.

The WIA platform includes a data acquisition protocol, a Device Driver Model and Interface (DDI), an API and a dedicated W IA service. The platform also includes a set of built-in kernel mode drivers that support communication with imaging devices locally C Onnected through USB, Serial/parallel, SCSI and FireWire interfaces. The WIA subsystem also includes a transparent compatibility layer which allows TWAIN compatible applications to employ and Use wia-driver-based devices.

network connected Imaging devices, Web Services for Devices (WSD) protocol can also is used from wia-compliant imaging Applicati ONS on Windows vista and windows 7 out of the box via a Wsd-wia class driver, shipped as part of Windows&nbs P Vista. The class driver converts WIA calls to WSD calls and vice versa and makes already existing WIA applications work with WSD Based scanners without any additional driver.

WIA drivers is made up of a user interface (UI) component and a core driver component, loaded into, different process Spaces:ui in the application space and the driver core in the WIA service space. The service runs in local System context in Windows XP and runs in local service context starting with Windows Server 2003 and Windows Vista for enhanced security against buggy or malicious drivers.

The WIA API set exposes imaging applications to still image acquisition hardware functionality by providing support for:

• enumeration of available image acquisition devices.
• Creating connections to multiple devices simultaneously.
• querying properties of devices in a standard and expandable manner.
• acquiring device data by using the and high performance transfer mechanisms.
• maintaining image properties across data transfers.
• Notification of Device status and scan event handling.

Windows added scripting support for WIA by releasing the WIA Automation Library in 2002 that is incorporated in Windows Vi STA as Windows Image Acquisition (WIA) Automation Layer and continues to bes a part of Windows 7. The WIA Automation Library provides end-to-end image acquisition capabilities to automation-enabled application Developmen T environments and programming languages such as Microsoft Visual Basic 6.0, Active Server Pages (ASP), VBScript and C #.

For Windows 7, WIA APIs has additional support to complement the already existing push-scanning support.

• Auto-configured device initiated scanning with scan parameters configured in the scanner on the device front panel.
• Automatic Source selection for device-initiated scan.

Facts about Windows Image Acquisition 2.0

• The data transfer mechanism in WIA 2.0 is stream based. The stream abstraction removes the distinction between different transfer types and also allows exchange of mutually agree D-upon metadata between device and application.
• WIA 2.0 subsystem also includes a basic image processing filter driver add-on that's optionally replaceable by the Scanne R driver, if the driver chooses to provide a customized image processing filter. The built-in filter enables post processing of images acquired through the scanner. Image processing filter also enables live software previews when small settings such as brightness and contrast is adjust Ed.
• The segmentation filter is another handy WIA component, can be replaced to a more customized filter by the scanner DRI Ver. The segmentation filter can used for multi-region scanning. Multi-region scanning, as an example, allows a application to automatically detect different scan regions without R intervention, such as identifying a bunch of photos lying randomly on the scanner flatbed.
• WIA 2.0 provides a replaceable/extensible error handler to gracefully handle, and possibly recover from, software, Hardwar E and configuration errors and delays. The error handler is another WIA component, can be replaced with a more customized version by the scanner driver. This extension provides status and error messages during data acquisitions such as "Lamp warming up," "Cover Open," "Paper Jam, "and so on. This extension also allows cleaner support for "Cancel operations."

Developer Audience

The WIA API is designed for use by C + + programmers. Familiarity with the Windows GUI and Component Object Model (COM) interfaces is required.

For developers familiar with Microsoft Visual Basic 6.0, Active servers Pages (ASP), or scripting, WIA provides an automati On-layer for Windows XP Service Pack 1 (SP1) or later-builds upon and simplifies access to the foundation provided by C + +. For information about the automation layer, Seewindows Image acquisition automation layer.

Note The WIA Automation Layer supersedes Windows Image Acquisition (WIA) 1.0 scripting.

Run-time Requirements

Applications that use the WIA API require Windows XP or later.

WIA Topics

The WIA topics is organized as shown in the following table.

About Windows Image acquisition	General information about WIA
Windows Image Acquisition Drivers	WIA Driver Development
Windows Image Acquisition Automation Layer	WIA Automation Layer
WIA Tutorial	Walkthrough of code included in the Software Development Kit (SDK) that focuses on specific tasks
Reference	Information on WIA interfaces, methods, objects, and data types used in C + + and scripting.

ZT <windows Image Acquisition (WIA) > from MSDN