Image Processing Reference
In-Depth Information
Fig. 2.15
To the
left
the amount of light which hits each cell is shown. To the
right
the resulting
image of the measured light is shown
Fig. 2.16
The effect of spatial resolution. The spatial resolution is from
left
to
right
: 256
×
256,
64
×
64, and 16
×
16
incident light hitting the cell, but not sensitive to where exactly the light hits the
cell. So if the shape should be preserved, the size of the cells should be infinitely
small. From this it follows that the image will be infinitively large in both the x- and
y-direction. This is not tractable and therefore a cell, of course, has a finite size. This
leads to loss of data/precision and this process is termed
spatial quantization
.The
effect is the blocky shape of the object in the figure to the right. The number of pixels
used to represent an image is also called the
spatial resolution
of the image. A high
resolution means that a large number of pixels are used, resulting in fine details in
the image. A low resolution means that a relatively low number of pixels is used.
Sometimes the words fine and coarse resolution are used. The visual effect of the
spatial resolution can be seen in Fig.
2.16
. Overall we have a trade-off between
memory and shape/detail preservation. It is possible to change the resolution of
an image by a process called
image-resampling
. This can be used to create a low
resolution image from a high resolution image. However, it is normally not possible
to create a high resolution image from a low resolution image.
