User`s guide

1 Gettin g Started
For pixel coordinates, the first comp onent r (the row) increases dow nward,
while the second component c (the column) increases to the right. Pixel
coordinates are integer values and range from 0 to the length of the row or
column. The pixel coordinates used in Video and Image Processing Blockset
are zero based, w hile the pixe l coordinates used by Image Processing Toolbox
and MATLAB are one based. For more information on the pixel coordinate
system used by Image Processing Toolbox, see “Pixel C oordinates” in the
Image Processing Toolbox documentation.
Spatial Coordinates
Spatial coordinates enable you to specify a location in an image with greater
granularity than pixel coordinates. For example, in the pixel coordinate
system, a pixel is treated as a discrete unit, uniquely identified by an integer
row and column pair, such as (3,4). In a spatial coordinate system, locations
in an image can be represented in terms of partial pixels, such as (3.3, 4.7).
The following figure illustrates the spatial coordinate system used for image s:
0
0
1
1
2
2
r
c
2.5
2.5
1.5
1.5
0.5
0.5
-0.5
-0.5
This spatial coordinate system corresponds to the pix el coordinate system
in the follow ing ways. First, both are defined in te rms of row a nd column
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