best_match ( Image : : MaxError, SubPixel, TemplateID : Row, Column, Error )
Searching the best matching of a template and an image.
The operator best_match performs a matching of the template
of TemplateID and Image.
Hereby the template will be moved over the points of Image
so that the template will lie always inside Image.
With regard to the parameter SubPixel, the position will
be indicated by subpixel accuracy.
The matching criterion (`"displaced frame difference'")
is defined as follows:
SUMu,v {ABS { Image[i-u][j-v] - Template[l-u][c-v] }}
error[i][j] = -----------------------------------------------------,
AREA ( Template )
The runtime of the procedure depends on the size of the domain of
Image.
Therefore it is important to restrict the domain as far as possible,
i.e. to apply the operator only in a very confined "region of interest".
The parameter MaxError determines the maximal error which the
searched position is allowed to show.
The lower this value is, the faster the procedure runs.
Row and Column return the position of the best match,
whereby Error indicates the average divergence of the grayvalues.
Parameters
Image (input_object)
|
image(-array) -> object : byte
|
Input image inside of which the pattern has to be found. |
MaxError (input_control)
|
real -> real
|
Maximum average difference of the grayvalues. |
Default value: 5 |
Suggested values: 0, 1, 2, 3, 4, 5, 6, 7, 9, 11, 15, 17, 20, 30 |
Range of values: 0 <= MaxError <= 255 |
Minimum increment: 1
|
Recommended increment: 1
|
SubPixel (input_control)
|
string -> string
|
Subpixel accuracy in case of 'true'. |
Default value: 'false' |
List of values: 'true', 'false' |
TemplateID (input_control)
|
integer -> integer
|
Template number. |
Default value: 0 |
Row (output_control)
|
number -> real / integer
|
Row position of the best match. |
Default value: 'false' |
Column (output_control)
|
number -> real / integer
|
Column position of the best match. |
Default value: 'false' |
Error (output_control)
|
real -> real
|
Average divergence of the grayvalues of the
best match. |
Default value: 'false' |
Result
If the parameter values are correct, the operator best_match
returns the value TRUE.
If the input is empty (no input images are available) the behaviour can
be set via set_system(::'no_object_result',<Result>:).
If necessary, an exception is raised.
Possible Predecessors
adapt_template,
draw_region,
draw_rectangle1,
reduce_domain
Alternatives
fast_match,
fast_mg_match,
match__,
mg_match__
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