Tool Window - Camera Control

Use the Camera Control tool window to acquire images and movies. In the Acquisition layout, this tool window is available by default. Should this tool window not be visible, use the View > Tool Windows > Camera Control command to show it.

Note: Some of the settings in the Camera Control tool window are camera specific (the available resolutions for example). For this reason, your camera's functionality can differ from what is described here.

Structure of the tool window

The tool window is made up of several parts. Click on one of the areas in the tool window shown below, to jump to the corresponding help topic.

Functions groups in the camera control

Showing/hiding function groups

The tool window contains a number of function groups, which you can use to make various settings for image acquisition. You can shrink the function groups so that only their headings are shown. This means that you can hide functions that you don't often use.

Click the small arrow next to the group name

to reduce the group's size. Click this arrow

to expand the group.

(1) The tool window's toolbar

In the Camera Control tool window, a number of buttons are at your disposal on the toolbar.

The following table lists the buttons which are available by default on the toolbar.

	Autofocus	Click the Autofocus button to have the image automatically focused.
	Focus Indicator	Click this button to make the Focus Indicator toolbar appear. Use this toolbar as a tool to help you bring the sample into focus.
	Focus Mode	Click this button to use Focus Mode when focusing the sample
	Line Profile	Click this button to have the Line Profile tool window displayed. This will enable you to measure the intensity profile on the current image along a line.
	Acquisition Settings	Open the Acquisition Settings dialog box. In it, you can change numerous settings for the image acquisition.
	Adjust Display	Click this button to open the Adjust Display tool window. This tool window offers you different possibilities for changing the appearance of the image. In addition, the histogram of the active image will be displayed in the tool window.
	Maximize to Screen	Click this button to see only the live image on your monitor. The user interface will be completely faded out.
	Load Camera Settings	Use saved camera settings for the image acquisition.
	Save Camera Settings	Save camera settings.

(2) Acquiring images

Acquiring images

Click the Live button to switch your camera to the live mode. The live-image will then be displayed in the image window. The button will change its appearance. This enables you to immediately recognize that you are in the live mode.

When you are in the live mode, click the Live button once more to end this mode without acquiring an image. You can change this behavior. To do so, use the Acquisition Settings > Acquisition > General dialog box. A description of this dialog box can be found here.

Navigating in the live mode

When you have carried out the Image Shift and Stage calibration processes for the current magnification, you can navigate in live mode by double clicking. Make sure that the mouse is in pan mode. You can find the Pan Tool button on the Toolbox toolbar.

In the pan mode your mouse pointer will take on the shape of a hand. Move your mouse pointer over the position on the sample you want. Double click on the position on the sample. The position on the sample moves to the center of the image window.

A four-pronged arrow next to the mouse pointer indicates whether it is possible to navigate using image shift or by movement of the stage. Based on the specified magnification and the calibrations that have been carried out, the software automatically selects whether the position on the sample is moved to by image shift or by movement of the stage.

•A white four-pronged arrow indicates that the stage is being moved to navigate to the position on the sample. Navigating using image shift is not possible.

•A green four-pronged arrow indicates that navigation is being achieved by image shift.

Click the Snapshot button to acquire a snapshot. The live mode will then, as a rule, be exited. The image you have acquired will be shown in the document group.

Image acquisition - several ways

Recording movies

Select the Movie recording check box if you want to acquire a movie. The buttons in the Camera Control tool window will then change both their appearance and functions.

•Select the Acquire > Movie menu command to start the movie recording. The Movie recording check box in the Camera Control tool window will now be automatically selected.

•Use the [F9] key to start the movie recording. The Movie recording check box in the Camera Control tool window will now be automatically selected.

Snapshot drift correction

Use the Snapshot drift correction function to reduce blurring on image segments that may result from the sample drifting. A sample with high contrast is required to carry out the drift correction. Note that the acquisition time of images is longer when drift correction is active.

Note: The Snapshot drift correction function is only available for the acquisition of snapshots. The Snapshot drift correction check box can only be selected when the Movie recording check box is not selected.

When you select the Snapshot drift correction check box and then click the Snapshot button, the camera acquires up to 16 images with a short, automatically determined exposure time. The software integrates these images into a new image. The resulting image only contains the image segments that are contained in all of the images.

MIA

Use the MIA (Multiple Image Alignment) function to have several individual images combined, as with a puzzle, into a stitched image. You will then get a high-resolution stitched image. Without MIA, acquiring a single image with this resolution would not be possible.

Note: The MIA check box can only be selected when the Movie recording check box is not selected.

The illustration shows left, four separate images. On the right, you see the stitched image made up from the four individual images.

(3) Selecting the camera

A transmission electron microscope has two different places where cameras can be mounted. A camera can be mounted below the microscope column or on the side of the microscope column. If you use two EMSIS cameras with your microscope, you can control both cameras with your software.

You have to register all cameras you want to use with your software, by using the Acquire > Devices > Device List... command. In the Camera Control tool window, you can find a picklist immediately below the Live and Snapshot buttons. Before you make an image acquisition, you will have to specify there, with which camera the acquisition is to be made. Select the camera you want from the list.

Note: All settings in the Camera Control tool window always relate to the currently selected camera. When you select a camera, you also automatically load the settings that were last selected for this camera.

(4) Adjusting the exposure time

The functions in the exposure time control depend on whether you choose to use the automatic exposure time option or to set the exposure time manually. The automatic exposure time is preset.

Automatic exposure time

In the automatic exposure time mode your system will continuously calculate the optimum exposure time for the snapshot. The snapshot acquisition always uses the last exposure time that was calculated in the automatic exposure time mode.

Select the Automatic (1) option to have the exposure time calculated automatically. The automatically determined exposure time is then displayed (2). Specify the image segment which will be used to calculate the exposure time (3).

The automatic exposure time for the snapshot will always be calculated on the basis of the histogram, that is, the intensity distribution in the live-image. If the live-image has a different resolution from the snapshot, this is automatically taken into account when computing the optimal exposure time. Use the Resolution group to set the camera resolution.

From the Region (3) list, select the image segment that is to be used for the calculation of the histogram and thus of the automatic exposure time.

Select the Full Image option so that the histogram of the entire image goes into the exposure time. This method is recommended if the structures to be observed are equally dispersed throughout the entire image.

Select the Spot option to have the histogram of only a rectangular image segment calculated. The size of the image segment is fixed, and depends on the camera you use. As soon as you switch to the live-image you will see a white dashed rectangle that identifies the relevant segment of the image. You can move the rectangle to any position in the image by dragging it there with your left mouse button pressed, and in this way you will then influence the exposure time. You can use this method if relevant details are only visible in a part of the image. The image acquisition can thus be optimized for precisely this segment of the image.

You can also change the image segment you've selected, however you want to, at any time.

Click the Center Spot on Image

button to have the image segment that is relevant for the exposure time returned to the center of the image.

Manual exposure time

Select the Manual option. Now you can enter any exposure time you want for the next snapshot. Use this mode if you want to compare the image intensity in different acquisitions with each other, for example.

If the live-image has a different resolution from the snapshot, this is taken into account for the live-image's exposure time.

Select the Manual (1) option to enter the exposure time yourself. Enter the exposure time you want in the field (2) or use the slide control (3) to set it. Please take note of the display (4).

•Enter an exposure time in the edit field (2), then press the [Enter] key. Or change the exposure time by using the arrow buttons next to the edit field.

•When the left arrow is green (1), the image is too dark. Increase the exposure time.

•When the right arrow is green (2), the image is too bright. Reduce the exposure time.

•When the right arrow is red (4) the image is overexposed, even though the camera is using the shortest possible exposure time. Reduce the beam intensity on the TEM.

•When the left arrow is red (5) the image is underexposed, even though the camera is using the longest possible exposure time. Increase the beam intensity on the TEM.

In this case, you can also increase the maximum possible exposure time. To do so, use the Acquisition Settings > Camera > Exposure dialog box.

Additional exposure time settings

Use the Acquisition Settings dialog box to make additional settings that effect your camera's exposure. For example, you can set a maximum exposure time.

Exposure time in the image properties

When each image acquisition is made, the exposure time will be adopted in the Properties tool window. You will find this information in the Camera group. This information will be retained if the image is saved in the TIF or VSI file format.

(5) Acquiring HDR images

Certain image modes (diffraction for example) can produce such strong differences in brightness that it is not possible to find an exposure time which is suitable for all parts of the sample. For such samples, an HDR image acquisition is recommended. HDR stands for High Dynamic Range. Dynamic range relates to the capacity of cameras, or image processing software, to display both bright and dark image segments.

The first illustration shows a diffraction image of Silicon that was acquired without HDR. The second illustration shows the same diffraction image of Silicon, this time acquired with HDR.

You can find detailed step-by-step instructions on how to acquire HDR images here.

(1) Activate HDR

Select the Activate HDR check box to activate this function. The Snap

button changes into the HDR

button.

Note: Selecting the Activate HDR check box simultaneously changes the acquisition mode used by the Acquire > Snapshot menu command and the Snapshot button located on the Camera Control toolbar. In contrast to the command name shown in the Camera Control tool window, the menu command is still named Snapshot, even when an HDR image is acquired.

(2) Determine exposure range

Before acquiring an HDR image, the necessary exposure range needs to be determined for the current sample. The exposure range is made up of a minimum and maximum exposure time as well as several exposure times between them.

In the Determine exposure range group, click the Automatically button to acquire the HDR image with an automatically defined exposure range.

In the Determine exposure range group, click the Manually... button to acquire the HDR image with a manually defined exposure range.

After determining the exposure range, the Total time field shows how long the HDR image acquisition will take.

(3) Preview HDR

Click the Preview HDR button to display a preview of the HDR image in the document group.

(6) Setting the resolution

You can set different resolutions for the live-image and the acquired image. Select the resolution you want from the Live/Movie list (1) or the Snap list (2).

Setting the camera resolution

Select the value you want for the resolution in the Live/Movie or Snapshot list. A resolution of 2048 x 2048 means, for example, that the image you acquire will be made up of 2048x2048=4194304 pixels.

Different resolution for live-image and snapshot

You can set a different (lower) resolution for the live-image than that which you use for the snapshot. That makes sense, for example, when you wish to have a live-image that reacts quickly, but want to use the maximum resolution for the acquisition of the snapshot.

What is binning?

With binning, the camera combines pixels to form larger pixels. Then less data will be transferred from the camera into the software, and the live-image will be updated more quickly. At the same time, the camera's sensitivity will increase, and the exposure time will become shorter.

(7) Averaging images

It possible to average several images during the image acquisition. Each image is acquired using the current camera settings. The images are added and, for each pixel, the mean value is calculated.

Enter the number of image that are to be used for the accumulation into the Frames fields.

Note: When you've activated averaging for the live-image and the image then changes substantially, the images that have already been averaged are discarded. The averaging is then restarted for the current position on the sample.

(8) Entering an image comment

In the Camera Control tool window, you can enter text in the Note field. This text will be saved along with the image as a comment.

Viewing a comment

After the image has been acquired, you can view the text in the Properties tool window's Note field. To do so, you can load the image and use the View > Tool Windows > Properties command to make the tool window appear.

Displaying the comment in the image window

You can have the image comment displayed in the image window, together with the info stamp. How you specify the contents of the info stamp, can be found here.

Deleting or editing comments for individual images

2.You will see that the comment you entered in the Camera Control tool window has been adopted in the Note field.