Acquiring SED and ABS Video Images

In AugerMap 2, SED and ABS images fall under the category of SEM (Scanning Electron Microscope) images, the term being loosely applied here to help differentiate between images that are topographical and elemental in nature. These are video images that will be representative of what your are seeing on your TV monitor or window at the time of acquisition (especially in the case of SED). However, both SED and ABS images will normally be of much better quality (and can be of higher resolution) then your TV image.

If you are going to be acquiring elemental maps, you’ll normally want to take at least one SED or ABS image in order to have a topographic reference image. This image is also very useful as the base image when creating a composite of all of your elemental maps.

Before acquiring an SED or ABS image, you must first have a reasonable TV image. Then the decision of whether to use SED or ABS for imaging is dependent on the application. SED is essential for high quality images, especially at high magnification. ABS is good for general positioning of a sample, if sufficient current is available and high resolution is not needed.

To acquire an SED or ABS image, click SEM in the Acquisition menu. This will bring up the Setup SEM Acquisition dialog. From this dialog, you can acquire (or re-acquire) multiple images (SED, ABS, or both). If you have not already acquired an SEM image, you may also setup your images without acquiring by clicking the Apply button. You may also acquire more than one of each type of image (for example, if you want to acquire two SED images at different resolutions).

The SEM Acquisition Dialog

SEM Image List

The SEM Image list is a list of all the SED and ABS images for this map. To add an SED image, simply click the Add SED button. To add an ABS image, click the Add ABS button. To remove an image, select the image from the list and click the Remove button.

Resolution

Use this drop-down box to select the resolution (XxY pixels) of the image. The choices available are 64x64, 128x128, 256x256, 512x512, and 1024x1024. The 512x512 resolution is probably the best compromise between image quality and time to acquire. 1024x1024 approaches photo-quality and is best if you plan on printing the image at a large size. 64x64 and 128x128 are most useful if you want a quick test to ensure your image capture and system controls are functioning properly (especially if you are planning on acquiring a large-resolution image later). 256x256 is a good all-purpose resolution if you just need a quick reference image – the quality is still good enough for placing points, areas, or lines on the map.

Comment

Type a comment in this field (optional) for the selected image. The comment will also appear in the Project Window, and on the printout, so it can be a useful reference.

Acquire All

Click this box if you wish to automatically acquire all the image in the list. If unchecked, only the selected acquisition will be acquired at this time. You can always acquire the other acquisitions later.

Acquire

Click this button to acquire the selected image, or all the images if you have that option selected (see above).

Apply

Click this button to apply the current settings for all images, without actually acquiring. You can then save the file, and use it later as a template. Note that, if you have acquired any SEM images, this button is inactive.

Acquisition Control

Evaluating Data During Acquisition

AugerMap displays the image as it is being acquired, so you can often easily tell if there are problems with the image quality. As new data is acquired, the image gray-scale range is automatically adjusted to take into account the min and max of the new data. Therefore, you may see the contrast of the image fluctuate as it adjusts to accommodate. The status bar at the bottom of the main AugerMap window will update with the current line being acquired, counts, and estimated time remaining. The counts may vary anywhere from the hundreds to thousands, depending on the type of image being acquired and the current settings. The overall range is usually not important, but if you are only see a fluctuation of less than a hundred, you will probably notice a lack of image depth and quality, and need to make some adjustments to your image setup to compensate.

To cancel the rest of an image acquisition (and any other images queued up afterwards), click Stop Now from the Acquisition menu. The acquisition will stop immediately. Note that this removes any previously collected data (for that image), since it is incomplete. To cancel any queued-up acquisitions after this one is complete, click Stop from the Acquisition menu.

After Acquisition

After acquisition, there are a number of actions you can take. You can annotate the image, or add a microm marker. You can also process, enhance, colorize, and invert the image. All of these commands are available from the image menu. You can also use the Project Window to delete the image.

Often, an image will need some adjustments to brightness and contrast before the quality is acceptable. This may be the case if there is any noise in the image. If there are a few pixels with very high counts in an image, this will lower the overall contrast. Brightness and contrast are adjusted using the Threshold and Gamma controls available from the Processing command in the Image menu. Click here for more information on image processing.

Lastly, saving, exporting, and printing commands are covered in the File Management topic.