best_matchT_best_matchBestMatchBestMatch (Operator)

Name

best_matchT_best_matchBestMatchBestMatch — Searching the best matching of a template and an image.

Warning

best_matchbest_matchBestMatchBestMatchBestMatch is obsolete and is only provided for reasons of backward compatibility. New applications should use the shape-based or NCC-based operators instead.

Signature

best_match(Image : : TemplateID, MaxError, SubPixel : Row, Column, Error)

Description

The operator best_matchbest_matchBestMatchBestMatchBestMatch performs a matching of the template of TemplateIDTemplateIDTemplateIDTemplateIDtemplateID and ImageImageImageImageimage. Hereby the template will be moved over the points of ImageImageImageImageimage so that the template will lie always inside ImageImageImageImageimage. best_matchbest_matchBestMatchBestMatchBestMatch works similar to fast_matchfast_matchFastMatchFastMatchFastMatch, with the exception, that each time a better match is found the value of MaxErrorMaxErrorMaxErrorMaxErrormaxError is internally updated to a lower value to reduce runtime.

With regard to the parameter SubPixelSubPixelSubPixelSubPixelsubPixel, the position will be indicated by subpixel accuracy. The matching criterion (“displaced frame difference”) is defined as follows: The runtime of the operator depends on the size of the domain of ImageImageImageImageimage. 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 MaxErrorMaxErrorMaxErrorMaxErrormaxError determines the maximal error which the searched position is allowed to have at most. The lower this value is, the faster the operator runs.

RowRowRowRowrow and ColumnColumnColumnColumncolumn return the position of the best match, whereby ErrorErrorErrorErrorerror indicates the average difference of the grayvalues. If no position with an error below MaxErrorMaxErrorMaxErrorMaxErrormaxError was found the position (0,0) and a matching result of 255 for ErrorErrorErrorErrorerror are returned. In this case MaxErrorMaxErrorMaxErrorMaxErrormaxError has to be set larger.

The maximum error of the position (without noise) is 0.1 pixel. The average error is 0.03 pixel.

Execution Information

Multithreading type: reentrant (runs in parallel with non-exclusive operators).
Multithreading scope: global (may be called from any thread).
Automatically parallelized on tuple level.

Parameters

ImageImageImageImageimage (input_object) singlechannelimage(-array) → object (byte)

Input image inside of which the pattern has to be found.

TemplateIDTemplateIDTemplateIDTemplateIDtemplateID (input_control) template → (handle)

Template number.

MaxErrorMaxErrorMaxErrorMaxErrormaxError (input_control) real → (real)

Maximum average difference of the grayvalues.

Default value: 20.0

Suggested values: 0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 9.0, 11.0, 15.0, 17.0, 20.0, 30.0, 40.0, 50.0, 60.0, 70.0

Typical range of values: 0 ≤ MaxError MaxError MaxError MaxError maxError ≤ 255

Minimum increment: 1

Recommended increment: 3

SubPixelSubPixelSubPixelSubPixelsubPixel (input_control) string → (string)

Subpixel accuracy in case of 'true'"true""true""true""true".

Default value: 'false' "false" "false" "false" "false"

List of values: 'false'"false""false""false""false", 'true'"true""true""true""true"

RowRowRowRowrow (output_control) point.y(-array) → (real)

Row position of the best match.

ColumnColumnColumnColumncolumn (output_control) point.x(-array) → (real)

Column position of the best match.

ErrorErrorErrorErrorerror (output_control) real(-array) → (real)

Average divergence of the grayvalues of the best match.

Result

If the parameter values are correct, the operator best_matchbest_matchBestMatchBestMatchBestMatch returns the value 2 (H_MSG_TRUE). If the input is empty (no input images are available) the behaviour can be set via set_system('no_object_result',<Result>)set_system("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>). If necessary, an exception is raised.

Possible Predecessors

create_templatecreate_templateCreateTemplateCreateTemplateCreateTemplate, read_templateread_templateReadTemplateReadTemplateReadTemplate, set_offset_templateset_offset_templateSetOffsetTemplateSetOffsetTemplateSetOffsetTemplate, set_reference_templateset_reference_templateSetReferenceTemplateSetReferenceTemplateSetReferenceTemplate, adapt_templateadapt_templateAdaptTemplateAdaptTemplateAdaptTemplate, draw_regiondraw_regionDrawRegionDrawRegionDrawRegion, draw_rectangle1draw_rectangle1DrawRectangle1DrawRectangle1DrawRectangle1, reduce_domainreduce_domainReduceDomainReduceDomainReduceDomain

Alternatives

fast_matchfast_matchFastMatchFastMatchFastMatch, fast_match_mgfast_match_mgFastMatchMgFastMatchMgFastMatchMg, best_match_mgbest_match_mgBestMatchMgBestMatchMgBestMatchMg, best_match_pre_mgbest_match_pre_mgBestMatchPreMgBestMatchPreMgBestMatchPreMg, best_match_rotbest_match_rotBestMatchRotBestMatchRotBestMatchRot, best_match_rot_mgbest_match_rot_mgBestMatchRotMgBestMatchRotMgBestMatchRotMg, exhaustive_matchexhaustive_matchExhaustiveMatchExhaustiveMatchExhaustiveMatch, exhaustive_match_mgexhaustive_match_mgExhaustiveMatchMgExhaustiveMatchMgExhaustiveMatchMg

Module

Matching

Operators