Unless you are using the high-level AcquireSimple function, you should first initialize a WIA session before using the features available in the LEADTOOLS WIA toolkit. This is done by call the Startup function. The Startup function initializes the session with multi-threading. so this function must be called before calling other LEADTOOLS WIA functions (except AcquireSimple). Note that for each call to Startup there must be a call to Shutdown.
WIA does not have a default device selection capability. Therefore, after establishing the WIA session, it is recommended that you select the WIA source to be used for acquiring images. For more information, refer to Managing WIA Sources.