Comet Labs WN591 Bedienungsanleitung PDF herunterladen (Seite 47)

Help! There is a comet in my computer! 44

Figure 26. Examples of contrast and brightness settings of the displayed image. For adjustment of

the camera settings, the contrast and brightness settings of the displayed image have to be set to

neutral, so that the actual grey values of the grabbed image are displayed. In example A, the

neutral settings of the displayed are brightness –0.5 and contrast 1.0 (and gamma correction factor

of the displayed image 1.0). In example B, the neutral display settings are brightness 0 and

contrast 0. In example C, a neutral contrast setting of the displayed image is achieved when the

image contrast is stretched across the whole range of available grey values, from 0 to 255.

Our final consideration goes to saving images of comets. If we are not using the “live”

mode for comet scoring, we have to record and save images before the measurement. It is

good practice to save images of measured comets even if we are working in the “live”

mode, to keep a record of the experiment. There are many formats available for saving

images (JPEG, TIF, BMP, GIF etc.). Images that are used for image analysis should be

stored in the TIFF format – this format preserves all information contained in the

recorded image, hence the image files are larger than in other formats and use up a lot of

computer memory. However, note that images saved in other formats, e.g. in the popular

JPEG format, get distorted during compression to make files smaller. Such distorted

images should not be used for measurements.

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Comet Labs WN591 Bedienungsanleitung Seite 47