|
Images
These are rather important and saving your images in the correct
format is a good idea. It may help if you consider these
facts:
 |
Images are made of pixels, and each pixel has
a certain brightness |
 |
The range of brightness (number of greylevels) within an
image varies with microscope and file format. Here the same range of
brightness can be quantified in either 8-bit, 12-bit or 16-bit. Same range,
different numbers
of greylevels between pure black and pure white.
(8-bit, 12-bit or 16-bit images actually look the same on a computer
screen as they are generally on capable of displaying 256 greylevels
for each
colour). |
|
It is often useful to consider the range of intensity values
within your image. The image histogram is graph of this information.
The range of intensities (ie number of gray levels)
in an image is important. Generally,
the more
greylevels
the
better. |
|
You will
get much
better contrast
in
the displayed image if the black to white
range
is matched
to the range
of
intensities
within the image.
Here is the histogram and image scaling from MetaMorph
(you might have done this with "levels" in photoshop). |
 |
These are the same image displayed with different scalings.
The image only has a fraction of the total dynamic range of the camera
-
The one on the left is set to display the entire range of intensities (even
though the brightest pixel in the image has an intensity of 819)
The image on the right
is displayed so the black-to-white scaling of the display better matches
the range of intensities in the image. |
 |
The same image can be displayed with different lookup tables.
- Black to white
- Black to red
- Rainbow
- Under/over (blue=0, red=saturated)
|
|
