Chang,
As far as I know you can't. It's that app that lets the user work with the scan device to choose scan area etc. You may be able to use the SendKeys() API call to issue the File, Start Scan menu item. If you want to use lower level access to the camera device you may have to go directly to TWAIN API calls.
> Can you tell me what is the event for image capture in teh Imaging Application ? i can call out the imaging application and start to scan by this.olescanner.startscan . the imaging form will appear on my screen and in the form will have a image capture button.
> How to avoid the imaging form come out on my screen and capture the image without use to click the capture button in the imaging form ?