Export

Export commands define scan area that is used later by the acquisition program to drive motors.

All scan parameters are stored into scan.dat file and copied to logbook file scan$.log, where $ is an unique integer. Both of files can be view and modified in any time.

3.8.2.1. Rectangular area

The command brings property sheet that lets you define a rectangular scan area with origin (left-bottom corner) that is related to one of the following:

• sample point that is in the front of capillary (or eventually shifted by a selected value) in the moment when you apply this property sheet (so called ‘blind’ scan)

• sample point selected on a two-dimensional image (XRF, extended XRF or video, which was active in the moment when you opened this property sheet)

The ‘blind’ scan area does not use any video or XRF image. Therefore, if you don’t have any referent image, you should use this property sheet to define valid starting scan area. Note that latter you can collect an XRF-image and use it to select new scan area, but blind scan area can be defined in any time.

In order to define blind rectangular scan area you should define its position and size. To define position you should move sample on such a way that origin (left-bottom corner) of the area you are interested in, is in the front of capillary. In the next step, you should enter current motor position in the ‘Position’ dialog. To do this check button ‘origin in the front of capillary…’. This allows you to enter the position either manually (as it is defined by motor application) or with using ‘read motor’ command.

If you define scan for the first time after positioning motors then select no shift (dx=0, dy=0) and check ‘set (x+dx, y+dy) as new referent position’. This sets origin of scan area in the front of capillary, and calibrates image on such a way that (0,0) mm is in the origin (the slope of calibration curve is defined by motors itself (see the Motor application).

Note that your scan area is well defined by the motor position (x,y) and can be easy reproduced. Later, if you want, you can scan area that is shifted by (dx,dy) mm from the current area. In this case, you can either keep current calibration offset or reset it. In the first case you should uncheck button ‘set (x+dx, y+dy) as new referent position’. This prevents program to move motor referent position. As the (0,0) coordinate in millimeters is always at point which is in the front of capillary when motors are in referent position your calibration does not change. Therefore, left top corner of the shifted scan area has no more (0,0) millimeters coordinate. In contrary, if you check the same button, then the program uses (x+dx,y+dy) as a new referent position and sets (0,0) coordinate in millimeters at origin of the shifted area. In any case, positive dx and dy shifts scan area to the right and up respectively, while negative dx and dy shifts it to the left and down side respectively.

Figure 3.8.2.1.1. The ‘Position’ dialog box of the ‘Rect, Scan Area’ property sheet.

If you want to define rectangular area relative to an image, then you don’t need to move motor manually. The origin (left-bottom corner) of the new scan area is defined by a point on any of images (XRF, extended XRF or video). The coordinates of selected point you should enter in the ‘Position’ dialog. Note, the program requires that selected image is active before you open ‘Scan Rectangular Area’. If you placed cursor at this point, than later you can enter coordinates by applying ‘read cursor’

command. If you want to place origin outside of the image select, then you can define corresponding (dx,dy) shift. The shift sign has the same convention as in the case of

‘blind’ scan.

Regardless of the origin the scan refers to, the size in millimeters of target XRF images (map collected using selected scan area) is equal to the size of the scan area and may be defined by the ‘Size’ dialog box.

The resolution of the target XRF-image, that is a distance in millimeters between two successive points, is equal to the size of the scan area divided by the number of channels in the target XRF-images. To change it, you should adjust the number of channels using the ‘Acquisition … Displays … Map Resolution’

command.

3.8.2.2. Image ROI

The command defines a scan region directly from an XRF, extended XRF or a video-image.

The images on which you define a scan area are called source images. The images that are collected from an exported scan area are called target XRF-images.

To define a scan region, you should first create a two-dimensional ROI on a source image (refer to ROI and Region menu for more information) and then apply the command. If you use a video image, the system must be optically calibrated (refer to 3.8.1 for more information).

The size in millimeters of the target XRF-images are the same and equal to the size of the scan frame. The scan frame is always rectangular, in difference from the scan border that may have any shape. If the source is a video image or extended XRF image, the frame is always defined as a smallest rectangle that surrounds selected scan area (ROI).

Figure 3.8.1.2. The ‘Size’ dialog box of the ‘Rect. Scan Area’ property sheet.

If the source is an XRF-image, you can optionally select the full frame of the source image as a scan frame. In that case, the size of the source and target XRF-images are the same. This is enabled by disabling ‘zoom’ in the ‘Scan Properties’

sheet. If the zoom is enabled, the scan frame size, hence the target XRF-image, is equal to the smallest rectangle.

The resolution in millimeters of the target XRF-image, that is the distance in millimeters between two successive points, is calculated automatically by the program. To do this, the program divides the size of the scan frame with the number of channels in the target XRF-image. To define the number of channels use

‘Acquisition… Display… Map Resolution’ dialog box. Note that source XRF image does not need to have neither equal number of channels nor the same resolution in millimeters comparing to the target XRF-image. Fig 3.8.2.2.1 illustrates effect of zooming on the target XRF-image if the number of channels does not change.