fast_thresholdfast_thresholdFastThresholdFastThresholdfast_threshold (算子名称)

名称

fast_thresholdfast_thresholdFastThresholdFastThresholdfast_threshold — Fast thresholding of images using global thresholds.

参数签名

fast_threshold(Image : 区域 : MinGray, MaxGray, MinSize : )

描述

fast_thresholdfast_thresholdFastThresholdFastThresholdFastThresholdfast_threshold selects the pixels from the input image whose gray values g fulfill the following condition:

To reduce the processing time, the selection is done in two steps: At first, all points lying on selected horizontal lines that are specified by their distance MinSizeMinSizeMinSizeMinSizeminSizemin_size are processed. In the next step the neighborhood (size (2*MinSize+1) x (2*MinSize+1)) of all previously selected points are processed.

注意

On multi-core computers supporting the SSE2 instruction set, thresholdthresholdThresholdThresholdThresholdthreshold is most likely faster than fast_thresholdfast_thresholdFastThresholdFastThresholdFastThresholdfast_threshold. fast_thresholdfast_thresholdFastThresholdFastThresholdFastThresholdfast_threshold may only be preferred to thresholdthresholdThresholdThresholdThresholdthreshold if those features are not available, e.g., on embedded platforms.

运行信息

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

参数表

ImageImageImageImageimageimage (input_object) singlechannelimage(-array) → object (byte / uint2 / direction / cyclic / real)

Input image.

区域区域区域区域区域区域 (output_object) region(-array) → object

Segmented regions.

MinGrayMinGrayMinGrayMinGrayminGraymin_gray (input_control) number → (real / integer)

Lower threshold for the gray values.

Default: 128

Suggested values: 0.0, 10.0, 30.0, 64.0, 128.0, 200.0, 220.0, 255.0

Value range: 0.0 ≤ MinGray MinGray MinGray MinGray minGray min_gray ≤ 255.0 (lin)

Minimum increment: 1

Recommended increment: 5.0

MaxGrayMaxGrayMaxGrayMaxGraymaxGraymax_gray (input_control) number → (real / integer)

Upper threshold for the gray values.

Default: 255.0

Suggested values: 0.0, 10.0, 30.0, 64.0, 128.0, 200.0, 220.0, 255.0

Value range: 0.0 ≤ MaxGray MaxGray MaxGray MaxGray maxGray max_gray ≤ 255.0 (lin)

Minimum increment: 1

Recommended increment: 5.0

MinSizeMinSizeMinSizeMinSizeminSizemin_size (input_control) number → (integer)

Minimum size of objects to be extracted.

Default: 20

Suggested values: 5, 10, 15, 20, 25, 30, 40, 50, 60, 70, 100

Value range: 2 ≤ MinSize MinSize MinSize MinSize minSize min_size ≤ 200 (lin)

Minimum increment: 1

Recommended increment: 2

Complexity

Let A be the area of the output region and height the height of ImageImageImageImageimageimage. Then the runtime complexity is O(A + height / MinSizeMinSizeMinSizeMinSizeminSizemin_size).

结果

fast_thresholdfast_thresholdFastThresholdFastThresholdFastThresholdfast_threshold returns 2 ( H_MSG_TRUE) if all parameters are correct. The behavior with respect to the input images and output regions can be determined by setting the values of the flags 'no_object_result'"no_object_result""no_object_result""no_object_result""no_object_result""no_object_result", 'empty_region_result'"empty_region_result""empty_region_result""empty_region_result""empty_region_result""empty_region_result", and 'store_empty_region'"store_empty_region""store_empty_region""store_empty_region""store_empty_region""store_empty_region" with set_systemset_systemSetSystemSetSystemSetSystemset_system. If necessary, an exception is raised.

可能的前置算子

histo_to_threshhisto_to_threshHistoToThreshHistoToThreshHistoToThreshhisto_to_thresh, min_max_graymin_max_grayMinMaxGrayMinMaxGrayMinMaxGraymin_max_gray, sobel_ampsobel_ampSobelAmpSobelAmpSobelAmpsobel_amp, binomial_filterbinomial_filterBinomialFilterBinomialFilterBinomialFilterbinomial_filter, gauss_filtergauss_filterGaussFilterGaussFilterGaussFiltergauss_filter, reduce_domainreduce_domainReduceDomainReduceDomainReduceDomainreduce_domain, fill_interlacefill_interlaceFillInterlaceFillInterlaceFillInterlacefill_interlace

可能的后置算子

connectionconnectionConnectionConnectionConnectionconnection, dilation1dilation1Dilation1Dilation1Dilation1dilation1, erosion1erosion1Erosion1Erosion1Erosion1erosion1, openingopeningOpeningOpeningOpeningopening, closingclosingClosingClosingClosingclosing, rank_regionrank_regionRankRegionRankRegionRankRegionrank_region, shape_transshape_transShapeTransShapeTransShapeTransshape_trans, skeletonskeletonSkeletonSkeletonSkeletonskeleton

可替代算子

thresholdthresholdThresholdThresholdThresholdthreshold, gen_grid_regiongen_grid_regionGenGridRegionGenGridRegionGenGridRegiongen_grid_region, dilation_rectangle1dilation_rectangle1DilationRectangle1DilationRectangle1DilationRectangle1dilation_rectangle1, dyn_thresholddyn_thresholdDynThresholdDynThresholdDynThresholddyn_threshold

参考其它

class_2dim_supclass_2dim_supClass2dimSupClass2dimSupClass2dimSupclass_2dim_sup, hysteresis_thresholdhysteresis_thresholdHysteresisThresholdHysteresisThresholdHysteresisThresholdhysteresis_threshold

模块

Foundation

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