ALACRON'S LABVIEW VI (VIRTUAL INSTRUMENT)

The ALACRON VI enables the software developer to interface Labview to Alacron frame grabbers.

THE ALACRON VI

Based on the ALACRON FASTMOTION LIBRARY(AFML) DLL the Alacron Vision VI’s provide methods to integrate Alacron Frame Grabbers into the National Instruments (NI) Lab View environment.  With Alacron Frame Grabbers and the Alacron Vision VI’s, you can control camera operations and manage images in array lists.  These image lists are compatible with the NI Vision Image reference and therefore can be modified, displayed, archived, or can be used as input to other devices.  These VI’s are supported in the National Instruments Lab View 8.5 environment when installed on the Microsoft Windows XP or Vista operating systems.  Understanding some of the concepts in this document requires knowledge of the National Instruments Lab View environment.

SUMMARY OF ALACRON VIS

This section provides a functional description of each of the Alacron Vision VI’s. 

Alacron Close Camera.vi

This VI takes a Cam Handle and Error as input and provides an Error as output.  The Close Camera VI stops any grab operation and closes the connection with the camera.  Executing this VI leaves the camera in a proper state for any future communication sessions. 

Alacron Dispose Image List.vi

This VI takes an Image List and Error as input and provides an Error as output.  The Dispose Image List VI frees memory that has been allocated when the image list was created and discards the image list. 

Alacron Get Camera File.vi

This VI has no inputs and provides a Camera File String and Error as output.  The Get Camera File VI retrieves the previous camera cap file used from the Windows registry.  This file string will only be available only if this VI has been executed previously.  If the previous camera cap file string is valid and the “Use Camera from Previous Session” check box is checked, this file string is sent to the Camera File String output.  If either of these conditions is not true, a list of camera cap files will be constructed by scanning files in the installed Program Files\Alacron\Camera Config Files directory (also retrieved from the Windows registry) and this list will be sent to the “Select Camera File” dropdown box.  After the list is created, the “Select Camera File and Press to Continue” button will blink as a prompt to select a file from the dropdown and continue by pressing that button.  If the VI executes correctly, no error will appear and the selected camera cap file path will be saved to the registry as the previous camera cap file used.  The Camera File String output is a filename and path that describes the location of the user selected camera configuration file.

Alacron Get Last Image Index.vi

This VI takes a Cam Handle and Error as inputs and provides a Cam Handle, Error and Last Image Index as outputs.  The last image index is the starting position of the last grab of images.  The output of the Get Last Image Index VI can be used as the input to the Update Image List VI to provide more accurate and timely update of image data captured in the last grab operation.

Alacron Init Image List.vi

This VI takes a Cam Handle and Error as inputs and provides a Cam Handle, Error and Image List as outputs.  The Init Image List VI queries the camera (frame grabber) for its total image storage capacity and creates a list and allocates memory for images of that size quatity.  The image size and image type are updated in the list, and each image is given a unique name (img0 - imgn).  The Init Image List VI does not retrieve image data and therefore, if immediately used, the images will appear black.  The Update Image List VI is used to update Image data from the camera.

Alacron Open Camera.vi

This VI takes a Camera File String and Error as inputs, and provides a Cam Handle and Error as outputs.  Open Camera VI opens and initializes the camera.   After executing this VI, the camera is ready to accept future commands using the Cam Handle out.  At the end of a session, the Alacron Close Camera VI should be executed to leave the camera in a proper state. 

Alacron Single Shot.vi

This VI takes a Cam Handle and Error as inputs, and provides a Cam Handle and Error as outputs.  The Single Shot VI grabs one frame of image data from the camera.

Alacron Start Grab.vi

This VI takes a Cam Handle and Error as inputs, and provides a Cam Handle and Error as outputs.  The Start Grab VI commands the camera to continuously grab frames of image data.  The Alacron Stop Grab VI is used to stop the continuous frame grabbing operation.

Alacron Stop Grab.vi

This VI takes a Cam Handle and Error as inputs, and provides a Cam Handle and Error as outputs.  The Stop Grab VI commands the camera to stop its frame grabbing operation. 

Alacron Update Image List.vi

This VI takes a Cam Handle, Start Index, Number of Images, Error, and Image List as inputs and provides a Cam Handle, Error and Image List as outputs.  The Update Image List VI updates the image list with images from the camera (frame grabber) starting at the beginning of the list or at the Start Index value provided at the input terminal.  To update the image list from the start of the last grab or single shot, wire the output of the Alacron Get Last Image Index VI to the Start Index value input terminal of this VI.  The Number of Images input terminal will cause the VI to update a subset of the image list or all images if this terminal is unwired or set to 0.  If no error condition has been detected, the output image list will contain updated images from the camera (frame grabber).

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