Detector image widget

The detector image

Most panels of the OpenHKL GUI contain some variation of the detector image widget, showing a single image from the data set (selectable via (1)). The scroll bar and spin box (2) can be used to cycle through the images in order, and the slider on the right of the widget used to adjust the maximum intensity of the colour map, which is useful for visually enhancing low contrast images.

In addition, there is a toolbar with several more controls:

3. Switch between normal image and image gradient

4. Toggle the resolution contours on and off

5. Toggle the detector masks on and offer

6. Toggle Miller indices of peaks on and off

7. Copy the image with all overlays to the clipboard

8. Save the image with all overlays to a file

9. Zoom select tool

10. Rectangle select tool

11. Change the information displayed in the tooltip attached to the cursor

The detector widget is by default in zoom mode, in which the user can drag a rectangular selection box, which will be zoomed into when the mouse button is released. A right mouse button click will zoom out one level.

Cursor mode

The Cursor mode combo box changes the information displayed in the tooltip attached to the mouse cursor when hovering over a pixel in the detector image. The options are:

1. Pixel — the pixel coordinates (x, y) followed by the count of the pixel

2. \(\theta\) — the diffraction angle \(\theta\) followed by the count

3. \(\gamma / \nu\) — the instrument angles \(\gamma\) and \(\nu\), followed by the count

4. d — The lattice spacing d from Bragg’s law followed by the count

5. Miller index — the non-integer Miller index \((h k l)\) followed by the count

Show/hide peaks widget

The show/hide peaks widget

Every detector widget has an assocated widget to change the peak visualisatioon settings on the control panel on the left of the application, in most cases, this is labeled Show/hide peaks. It enables control of three different aspects of the information superimposed on the detector image:

Valid peaks

Plot peak centres as circles on the detector image.

1. Show or hide the valid peaks (peaks which are selected and not masked)

2. Change the size of the circle indicating the centre of the peak

3. Change the colour of the circle indicating the centre of the peak

Integration Regions

Generate an overlay indicating the peak intensity regions (default green) and background regions (default yellow).

4. Show or hide the integration regions

5. Change the alpha (transparency) of the integration regions; 0 = transparent, 1 = opaque.

6. Set the colour of the peak (intensity) region

7. Set the colour of the background region

8. Preview the integration regions. If this is checked, the integration parameters below are used to determine the size of the integration regions. If unchecked, the integration regions are determined from the parameters used last time the peaks were integrated.

9. Peak region size (see Definition of peak shape)

10. Beginning of background region (see Definition of peak shape)

11. End of background region (see Definition of peak shape)

Invalid peaks

Plot peaks that have for some reason been disabled as circles on the detector image.

13. Show or hide the invalid peaks

14. Change the size of the circle indicating the centre of the peak

15. Change the colour of the circle indicating the centre of the peak