Description of Units¶
Specific to This Project¶
Ratios¶
A ratio is expressed as a fraction of the appropriate dimension.
For example, an x-coordinate of 30 when the width is 100 is
expressed as a ratio as 0.3. This allows coordinates to be
transferred between images of varying dimensions.
A box_ratio is a Tuple of 4 floats that describes a rectangular region in
the following format:
(start_x, start_y, end_x, end_y)
Each value of the Tuple is a ratio as defined above. (start_x, start_y)
defines the coordinates of one corner of the rectangle, and (end_x, end_y)
defines the opposing corner.
Coordinates¶
A coordinate is a pair of numbers of the form (x, y) that defines a
particular point on the image. The coordinate system, as is standard in computer
science, places (0,0) in the upper-left corner while x increases to the
right and y increases downward. Coordinates are “absolute”, not relative to
the size of the image, so the point (5,5) is in the middle of a 10 x 10
image, but in the lower right of a 5 x 5 image.
A box_coor is a Tuple of 4 floats that describes a rectangular region in the
following format:
(start_x, start_y, end_x, end_y)
(start_x, start_y) is a coordinate for one corner of the rectangle, while
(end_x, end_y) is a coordinate of the opposing corner.