Comet Labs WN591 Bedienungsanleitung PDF herunterladen (Seite 44)

Help! There is a comet in my computer! 41

the signal at a high enough resolution to allow for reliable measurement of the comet

profile. The optimal setting of binning for recording of comets depends on the properties of

the equipment for comet measurement (the full resolution of the camera, the magnification

of the objective etc.) and on the size of scored nuclei and comets (smaller comets require a

higher resolution of the image, weaker comets require higher sensitivity).

Note that binning affects the scaling factor of the image (Figure 24).

Figure 24. The effects of binning. Only the part of the recorded image that contains the comet is

shown here to illustrate the effects of binning. A: The image was grabbed at full resolution of the

camera without binning. The size of the image is 280 × 230 pixels and it contains 64400 pixels. The

image scaling factor is 0.36 µm per pixel. B: The image was grabbed at binning 2×2. The size of

the image is 140 × 115 pixels and it contains 16100 pixels. The image scaling factor is 0.72 µm per

pixel.

5.9 Which image does my software measure?

We have seen that after we grab an image of a comet we can change the way it is displayed

on the screen. In some comet software packages, we can adjust the settings of the

displayed image, using contrast and brightness tools and applying LUTs. This can help us

see the comets and determine where the borders of the comet are in the displayed image.

In principle, any comet software should save the original grabbed image of a comet in a

very safe place that the user cannot access. After the user confirms the positions of the

comet ROIs, the computer should perform the measurements on this original image and on

no other derivative of it. The grabbed image contains all available information on the

comet, and information can only get lost or distorted by any later fiddling with the image.

However, this is not always the case in practice. The problem arises if our software uses

the changed displayed image to measure the comet parameters, and not the original image.

If this is the case, we have to use the display options very carefully, and make sure that

1 2 ... 39 40 41 42 43 44 45 46 47 48 49

Keine Kommentare

Comet Labs WN591 Bedienungsanleitung Seite 44