best_matchT_best_matchBestMatchBestMatchbest_match (Operator)

Name

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

Warning

best_matchbest_matchBestMatchBestMatchBestMatchbest_match is obsolete and is only provided for reasons of backward compatibility.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_matchBestMatchBestMatchBestMatchbest_match performs a matching of the template of TemplateIDTemplateIDTemplateIDTemplateIDtemplateIDtemplate_id and ImageImageImageImageimageimage. Hereby the template will be moved over the points of ImageImageImageImageimageimage so that the template will lie always inside ImageImageImageImageimageimage. best_matchbest_matchBestMatchBestMatchBestMatchbest_match works similar to fast_matchfast_matchFastMatchFastMatchFastMatchfast_match, with the exception, that each time a better match is found the value of MaxErrorMaxErrorMaxErrorMaxErrormaxErrormax_error is internally updated to a lower value to reduce runtime.

With regard to the parameter SubPixelSubPixelSubPixelSubPixelsubPixelsub_pixel, 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 ImageImageImageImageimageimage. 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 MaxErrorMaxErrorMaxErrorMaxErrormaxErrormax_error determines the maximal error which the searched position is allowed to have at most. The lower this value is, the faster the operator runs.

RowRowRowRowrowrow and ColumnColumnColumnColumncolumncolumn return the position of the best match, whereby ErrorErrorErrorErrorerrorerror indicates the average difference of the gray values. If no position with an error below MaxErrorMaxErrorMaxErrorMaxErrormaxErrormax_error was found the position (0,0) and a matching result of 255 for ErrorErrorErrorErrorerrorerror are returned. In this case MaxErrorMaxErrorMaxErrorMaxErrormaxErrormax_error 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

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

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

TemplateIDTemplateIDTemplateIDTemplateIDtemplateIDtemplate_id (input_control) template → (handle)

Template number.

MaxErrorMaxErrorMaxErrorMaxErrormaxErrormax_error (input_control) real → (real)

Maximum average difference of the gray values.

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 max_error ≤ 255

Minimum increment: 1

Recommended increment: 3

SubPixelSubPixelSubPixelSubPixelsubPixelsub_pixel (input_control) string → (string)

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

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

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

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

Row position of the best match.

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

Column position of the best match.

ErrorErrorErrorErrorerrorerror (output_control) real(-array) → (real)

Average divergence of the gray values of the best match.

Result

If the parameter values are correct, the operator best_matchbest_matchBestMatchBestMatchBestMatchbest_match returns the value TRUE. If the input is empty (no input images are available) the behavior 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>)set_system("no_object_result",<Result>). If necessary, an exception is raised.

Possible Predecessors

create_templatecreate_templateCreateTemplateCreateTemplateCreateTemplatecreate_template, read_templateread_templateReadTemplateReadTemplateReadTemplateread_template, set_offset_templateset_offset_templateSetOffsetTemplateSetOffsetTemplateSetOffsetTemplateset_offset_template, set_reference_templateset_reference_templateSetReferenceTemplateSetReferenceTemplateSetReferenceTemplateset_reference_template, adapt_templateadapt_templateAdaptTemplateAdaptTemplateAdaptTemplateadapt_template, draw_regiondraw_regionDrawRegionDrawRegionDrawRegiondraw_region, draw_rectangle1draw_rectangle1DrawRectangle1DrawRectangle1DrawRectangle1draw_rectangle1, reduce_domainreduce_domainReduceDomainReduceDomainReduceDomainreduce_domain

Alternatives

fast_matchfast_matchFastMatchFastMatchFastMatchfast_match, fast_match_mgfast_match_mgFastMatchMgFastMatchMgFastMatchMgfast_match_mg, best_match_mgbest_match_mgBestMatchMgBestMatchMgBestMatchMgbest_match_mg, best_match_pre_mgbest_match_pre_mgBestMatchPreMgBestMatchPreMgBestMatchPreMgbest_match_pre_mg, best_match_rotbest_match_rotBestMatchRotBestMatchRotBestMatchRotbest_match_rot, best_match_rot_mgbest_match_rot_mgBestMatchRotMgBestMatchRotMgBestMatchRotMgbest_match_rot_mg, exhaustive_matchexhaustive_matchExhaustiveMatchExhaustiveMatchExhaustiveMatchexhaustive_match, exhaustive_match_mgexhaustive_match_mgExhaustiveMatchMgExhaustiveMatchMgExhaustiveMatchMgexhaustive_match_mg

Module

Matching

Operators