check_differencecheck_differenceCheckDifferenceCheckDifferencecheck_difference (Operator)

Name

check_differencecheck_differenceCheckDifferenceCheckDifferencecheck_difference — Compare two images pixel by pixel.

Signature

check_difference(Image, Pattern : Selected : Mode, DiffLowerBound, DiffUpperBound, GrayOffset, AddRow, AddCol : )

Description

check_differencecheck_differenceCheckDifferenceCheckDifferencecheck_difference selects from the input image ImageImageImageimageimage those pixels (), whose gray value difference to the corresponding pixels in PatternPatternPatternpatternpattern is inside (outside) of the interval . The pixels of PatternPatternPatternpatternpattern are translated by with respect to ImageImageImageimageimage. Let be the gray value from PatternPatternPatternpatternpattern translated by with respect to .

If the selected mode ModeModeModemodemode is 'diff_inside'"diff_inside""diff_inside""diff_inside""diff_inside", a pixel is selected if If the mode is set to 'diff_outside'"diff_outside""diff_outside""diff_outside""diff_outside", a pixel is selected if g_o - g_p - GrayOffset < DiffLowerBound or g_o - g_p - GrayOffset > DiffUpperBound. This test is performed for all points of the domain (region) of ImageImageImageimageimage, intersected with the domain of the translated PatternPatternPatternpatternpattern. All points fulfilling the above condition are aggregated in the output region. The two images may be of different size. Typically, PatternPatternPatternpatternpattern is smaller than ImageImageImageimageimage.

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.

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

Comparison image.

SelectedSelectedSelectedselectedselected (output_object) region(-array) → object

Points in which the two images are similar/different.

ModeModeModemodemode (input_control) string → (string)

Mode: return similar or different pixels.

Default: 'diff_outside' "diff_outside" "diff_outside" "diff_outside" "diff_outside"

Suggested values: 'diff_inside'"diff_inside""diff_inside""diff_inside""diff_inside", 'diff_outside'"diff_outside""diff_outside""diff_outside""diff_outside"

DiffLowerBoundDiffLowerBoundDiffLowerBounddiffLowerBounddiff_lower_bound (input_control) number → (integer)

Lower bound of the tolerated gray value difference.

Default: -5

Suggested values: 0, -1, -2, -3, -5, -7, -10, -12, -15, -17, -20, -25, -30

Value range: -255 ≤ DiffLowerBound DiffLowerBound DiffLowerBound diffLowerBound diff_lower_bound ≤ 255 (lin)

Minimum increment: 1

Recommended increment: 2

DiffUpperBoundDiffUpperBoundDiffUpperBounddiffUpperBounddiff_upper_bound (input_control) number → (integer)

Upper bound of the tolerated gray value difference.

Default: 5

Suggested values: 0, 1, 2, 3, 5, 7, 10, 12, 15, 17, 20, 25, 30

Value range: -255 ≤ DiffUpperBound DiffUpperBound DiffUpperBound diffUpperBound diff_upper_bound ≤ 255 (lin)

Minimum increment: 1

Recommended increment: 2

GrayOffsetGrayOffsetGrayOffsetgrayOffsetgray_offset (input_control) number → (integer)

Offset gray value subtracted from the input image.

Default: 0

Suggested values: -30, -25, -20, -17, -15, -12, -10, -7, -5, -3, -2, -1, 0, 1, 2, 3, 5, 7, 10, 12, 15, 17, 20, 25, 30

Value range: -255 ≤ GrayOffset GrayOffset GrayOffset grayOffset gray_offset ≤ 255 (lin)

Minimum increment: 1

Recommended increment: 2

AddRowAddRowAddRowaddRowadd_row (input_control) point.y → (integer)

Row coordinate by which the comparison image is translated.

Default: 0

Suggested values: -200, -100, -20, -10, 0, 10, 20, 100, 200

Value range: -32000 ≤ AddRow AddRow AddRow addRow add_row ≤ 32000 (lin)

Minimum increment: 1

Recommended increment: 1

AddColAddColAddColaddColadd_col (input_control) point.x → (integer)

Column coordinate by which the comparison image is translated.

Default: 0

Suggested values: -200, -100, -20, -10, 0, 10, 20, 100, 200

Value range: -32000 ≤ AddCol AddCol AddCol addCol add_col ≤ 32000 (lin)

Minimum increment: 1

Recommended increment: 1

Complexity

Let be the number of valid pixels. Then the runtime complexity is .

Result

check_differencecheck_differenceCheckDifferenceCheckDifferencecheck_difference 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", '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" with set_systemset_systemSetSystemSetSystemset_system. If necessary, an exception is raised.

Possible Successors

connectionconnectionConnectionConnectionconnection, select_shapeselect_shapeSelectShapeSelectShapeselect_shape, reduce_domainreduce_domainReduceDomainReduceDomainreduce_domain, select_grayselect_graySelectGraySelectGrayselect_gray, rank_regionrank_regionRankRegionRankRegionrank_region, dilation1dilation1Dilation1Dilation1dilation1, openingopeningOpeningOpeningopening

Alternatives

sub_imagesub_imageSubImageSubImagesub_image, dyn_thresholddyn_thresholdDynThresholdDynThresholddyn_threshold

Module

Foundation

Operators