Plugin lcvimgproc

This module contains elements for image processing. It resembles open cv's imgproc module.

import lcvimgproc 1.0

Summary

TypePanAndZoom	UI component to perform panning and zooming on a given Mat object.
TypeBlur	Blurs an image using the normalized box filter.
TypeCanny	Finds edges within an image.
TypeGaussianBlur	Blurs an image using a Gaussian filter.
TypeHoughLinesP	Finds line segments in a binary image using the probabilistic Hough transform.
TypeHoughLines	Finds line segments in a binary image using the Hough transform.
TypeSobel	Calculates the first, second, third, or mixed image derivatives using an extended Sobel operator.
TypeCvtColor	Converts an image from one color space to another.
TypeThreshold	Applies a fixed-level threshold to each element.
TypeChannelSelect	Selects an image channel by its index.
TypeStructuringElement	Creates a structuring element of the specified size and shape for morphological operations.
TypeResize	Resizes an image.
TypeFilter2D	Converts an image with the specified kernel.
TypeDilate	Erodes an image by using a specific structuring element.
TypeErode	Dilates an image by using a specific structuring element.
TypeCopyMakeBorder	Copies the source image into the middle of the destination image.
TypeDraw	Draws an ellipse.
TypeGetPerspectiveTransform	Calculates a perspective transform from four pairs of the corresponding points.
TypewarpPerspective	Applies a perspective transformation to an image.
TypeQCachedWarpPerspective	Applies a perspective transformation to an image.

PanAndZoom type

Inherits

MatFilter

Property	Mat input
Property	int regionWidth
Property	int regionWidth
Property	int regionX
Property	int regionY
Property	color SelectionColor

UI component to perform panning and zooming on a given Mat object.

Mat input property

input matrix to perform PanAndZoom on

int regionWidth property

width of the region to select out of the matrix

int regionWidth property

height of the region to select out of the matrix

int regionX property

x coordinate to start the selection from

int regionY property

y coordinate to start the selection from

color SelectionColor property

color for selection rectangle

Blur type

Inherits

MatFilter

Property	Size ksize
Property	Point anchor
Property	int borderType

Blurs an image using the normalized box filter.

The function smoothes an image using the normalized box filter.

quotefile imgproc/blur.qml

Size ksize property

Blurring kernel size.

Point anchor property

Anchor point; default value Point(-1,-1) means that the anchor is at the kernel center.

int borderType property

Border mode used to extrapolate pixels outside of the image.

See also CopyMakeBorder::BorderType

Canny type

Inherits

MatFilter

Property	int threshold1
Property	Size threshold2
Property	Size apertureSize
Property	Size l2gradient

Finds edges within an image.

Canny finds edges in the input image image and marks them in the output map edges using the Canny algorithm. The smallest value between threshold1 and threshold2 is used for edge linking. The largest value is used to find initial segments of strong edges

quotefile imgproc/canny.qml

int threshold1 property

First threshold for the hysteresis procedure.

Size threshold2 property

Second threshold for the hysteresis procedure.

Size apertureSize property

Aperture size for the Sobel() operator.

Size l2gradient property

A flag indicating whether a more accurate L2 norm should be used to calculate the image gradient magnitude.

GaussianBlur type

Inherits

MatFilter

Property	size ksize
Property	real sigmaX
Property	real sigmaY
Property	int borderType

Blurs an image using a Gaussian filter.

imgproc/gaussianblur.qml

size ksize property

Gaussian kernel size. ksize.width and ksize.height can differ but they both must be positive and odd. Or, they can be zero’s and then they are computed from sigma.

real sigmaX property

Gaussian kernel standard deviation in X direction.

real sigmaY property

Gaussian kernel standard deviation in Y direction.

int borderType property

Pixel extrapolation method (see CopyMakeBorder::BorderType for details).

HoughLinesP type

Inherits

MatFilter

Property	real rho
Property	real theta
Property	int threshold
Property	real minLineLength
Property	real maxLineGap
Property	color lineColor
Property	int lineThickness

Finds line segments in a binary image using the probabilistic Hough transform.

imgproc/houghlinesp.qml

real rho property

Distance resolution of the accumulator in pixels.

real theta property

Angle resolution of the accumulator in radians.

int threshold property

Accumulator threshold parameter. Only those lines are returned that get enough votes ( > threshold ).

real minLineLength property

Minimum line length. Line segments shorter than that are rejected.

real maxLineGap property

Maximum allowed gap between points on the same line to link them.

color lineColor property

Color of the lines being drawn.

int lineThickness property

Thickness of the lines being drawn.

HoughLines type

Inherits

MatFilter

Property	int threshold
Property	real srn
Property	real stn
Property	color lineColor
Property	int lineThickness

Finds line segments in a binary image using the Hough transform.

imgproc/houghlines.qml

Distance resolution of the accumulator in pixels.

Angle resolution of the accumulator in radians.

int threshold property

Accumulator threshold parameter. Only those lines are returned that get enough votes ( > threshold ).

real srn property

For the multi-scale Hough transform, it is a divisor for the distance resolution rho . The coarse accumulator distance resolution is rho and the accurate accumulator resolution is rho/srn . If both srn=0 and stn=0 , the classical Hough transform is used. Otherwise, both these parameters should be positive.

real stn property

For the multi-scale Hough transform, it is a divisor for the distance resolution theta.

color lineColor property

Color of the lines being drawn.

int lineThickness property

Thickness of the lines being drawn.

Sobel type

Inherits

MatFilter

Property	Mat Type ddepth
Property	int xorder
Property	int yorder
Property	int ksize
Property	real scale
Property	real delta
Property	real borderType

Calculates the first, second, third, or mixed image derivatives using an extended Sobel operator.

imgproc/sobeloperator.qml

Mat Type ddepth property

Output image depth, the following combinations of input depth and ddepth are supproted:

• input.depth = Mat.CV8U, ddepth = -1 / Mat.CV16S / Mat.CV32F / Mat.CV64F

• input.depth = Mat.CV16U / Mat.CV16S, ddepth = -1 / Mat.CV32F / Mat.CV64F

• input.depth = Mat.CV32F, ddepth = -1 / Mat.CV32F / Mat.CV64F

• input.depth = Mat.64F, ddepth = -1 / Mat.CV64F

  When ddepth = -1, the destination image will have the same depth as the source. In case of 8-bit input images, it will result in truncated derivatives.

int xorder property

Order of the derivative in x.

int yorder property

Order of the derivative in y.

int ksize property

Size of the extended Sobel kernel; ( must be 1, 3, 5, 7 )

real scale property

Optional scale factor for the computed derivative values; by default, no scaling is applied.

real delta property

Optional delta value that is added to the results prior to storing them in output.

real borderType property

Pixel extrapolation method.

See also CopyMakeBorder::BorderType

CvtColor type

Inherits

MatFilter

Property	enumeration CvtType
Property	CvtType code
Property	int dstCn

Converts an image from one color space to another.

imgproc/threshold.qml

enumeration CvtType property

Conversion method:

• CV_BGR2BGRA

• CV_RGB2RGBA

• CV_BGRA2BGR

• CV_RGBA2RGB

• CV_BGR2RGBA

• CV_RGB2BGRA

• CV_RGBA2BGR

• CV_BGRA2RGB

• CV_BGR2RGB

• CV_RGB2BGR

• CV_BGRA2RGBA

• CV_RGBA2BGRA

• CV_BGR2GRAY

• CV_RGB2GRAY

• CV_GRAY2BGR

• CV_GRAY2RGB

• CV_GRAY2BGRA

• CV_GRAY2RGBA

• CV_BGRA2GRAY

• CV_RGBA2GRAY

• CV_BGR2BGR565

• CV_RGB2BGR565

• CV_BGR5652BGR

• CV_BGR5652RGB

• CV_BGRA2BGR565

• CV_RGBA2BGR565

• CV_BGR5652BGRA

• CV_BGR5652RGBA

• CV_GRAY2BGR565

• CV_BGR5652GRAY

• CV_BGR2BGR555

• CV_RGB2BGR555

• CV_BGR5552BGR

• CV_BGR5552RGB

• CV_BGRA2BGR555

• CV_RGBA2BGR555

• CV_BGR5552BGRA

• CV_BGR5552RGBA

• CV_GRAY2BGR555

• CV_BGR5552GRAY

• CV_BGR2XYZ

• CV_RGB2XYZ

• CV_XYZ2BGR

• CV_XYZ2RGB

• CV_BGR2YCrCb

• CV_RGB2YCrCb

• CV_YCrCb2BGR

• CV_YCrCb2RGB

• CV_BGR2HSV

• CV_RGB2HSV

• CV_BGR2Lab

• CV_RGB2Lab

• CV_BayerBG2BGR

• CV_BayerGB2BGR

• CV_BayerRG2BGR

• CV_BayerGR2BGR

• CV_BayerBG2RGB

• CV_BayerGB2RGB

• CV_BayerRG2RGB

• CV_BayerGR2RGB

• CV_BGR2Luv

• CV_RGB2Luv

• CV_BGR2HLS

• CV_RGB2HLS

• CV_HSV2BGR

• CV_HSV2RGB

• CV_Lab2BGR

• CV_Lab2RGB

• CV_Luv2BGR

• CV_Luv2RGB

• CV_HLS2BGR

• CV_HLS2RGB

• CV_BayerBG2BGR_VNG

• CV_BayerGB2BGR_VNG

• CV_BayerRG2BGR_VNG

• CV_BayerGR2BGR_VNG

• CV_BayerBG2RGB_VNG

• CV_BayerGB2RGB_VNG

• CV_BayerRG2RGB_VNG

• CV_BayerGR2RGB_VNG

• CV_BGR2HSV_FULL

• CV_RGB2HSV_FULL

• CV_BGR2HLS_FULL

• CV_RGB2HLS_FULL

• CV_HSV2BGR_FULL

• CV_HSV2RGB_FULL

• CV_HLS2BGR_FULL

• CV_HLS2RGB_FULL

• CV_LBGR2Lab

• CV_LRGB2Lab

• CV_LBGR2Luv

• CV_LRGB2Luv

• CV_Lab2LBGR

• CV_Lab2LRGB

• CV_Luv2LBGR

• CV_Luv2LRGB

• CV_BGR2YUV

• CV_RGB2YUV

• CV_YUV2BGR

• CV_YUV2RGB

• CV_BayerBG2GRAY

• CV_BayerGB2GRAY

• CV_BayerRG2GRAY

• CV_BayerGR2GRAY

• CV_YUV2RGB_NV12

• CV_YUV2BGR_NV12

• CV_YUV2RGB_NV21

• CV_YUV2BGR_NV21

• CV_YUV420sp2RGB

• CV_YUV420sp2BGR

• CV_YUV2RGBA_NV12

• CV_YUV2BGRA_NV12

• CV_YUV2RGBA_NV21

• CV_YUV2BGRA_NV21

• CV_YUV420sp2RGBA

• CV_YUV420sp2BGRA

• CV_YUV2RGB_YV12

• CV_YUV2BGR_YV12

• CV_YUV2RGB_IYUV

• CV_YUV2BGR_IYUV

• CV_YUV2RGB_I420

• CV_YUV2BGR_I420

• CV_YUV420p2RGB

• CV_YUV420p2BGR

• CV_YUV2RGBA_YV12

• CV_YUV2BGRA_YV12

• CV_YUV2RGBA_IYUV

• CV_YUV2BGRA_IYUV

• CV_YUV2RGBA_I420

• CV_YUV2BGRA_I420

• CV_YUV420p2RGBA

• CV_YUV420p2BGRA

• CV_YUV2GRAY_420

• CV_YUV2GRAY_NV21

• CV_YUV2GRAY_NV12

• CV_YUV2GRAY_YV12

• CV_YUV2GRAY_IYUV

• CV_YUV2GRAY_I420

• CV_YUV420sp2GRAY

• CV_YUV420p2GRAY

• CV_YUV2RGB_UYVY

• CV_YUV2BGR_UYVY

• CV_YUV2RGB_Y422

• CV_YUV2BGR_Y422

• CV_YUV2RGB_UYNV

• CV_YUV2BGR_UYNV

• CV_YUV2RGBA_UYVY

• CV_YUV2BGRA_UYVY

• CV_YUV2RGBA_Y422

• CV_YUV2BGRA_Y422

• CV_YUV2RGBA_UYNV

• CV_YUV2BGRA_UYNV

• CV_YUV2RGB_YUY2

• CV_YUV2BGR_YUY2

• CV_YUV2RGB_YVYU

• CV_YUV2BGR_YVYU

• CV_YUV2RGB_YUYV

• CV_YUV2BGR_YUYV

• CV_YUV2RGB_YUNV

• CV_YUV2BGR_YUNV

• CV_YUV2RGBA_YUY2

• CV_YUV2BGRA_YUY2

• CV_YUV2RGBA_YVYU

• CV_YUV2BGRA_YVYU

• CV_YUV2RGBA_YUYV

• CV_YUV2BGRA_YUYV

• CV_YUV2RGBA_YUNV

• CV_YUV2BGRA_YUNV

• CV_YUV2GRAY_UYVY

• CV_YUV2GRAY_YUY2

• CV_YUV2GRAY_Y422

• CV_YUV2GRAY_UYNV

• CV_YUV2GRAY_YVYU

• CV_YUV2GRAY_YUYV

• CV_YUV2GRAY_YUNV

• CV_RGBA2mRGBA

• CV_mRGBA2RGBA

• CV_COLORCVT_MAX

CvtType code property

Color space conversion code.

int dstCn property

Number of channels in the destination image; if the parameter is 0, the number of the channels is derived automatically from input and code.

Threshold type

Inherits

MatFilter

Property	enumeration Type
Property	int thresh
Property	int maxVal
Property	Type thresholdType

Applies a fixed-level threshold to each element.

The function applies fixed-level thresholding to a single-channel array. The function is typically used to get a bi-level (binary) image out of a grayscale image ( compare() could be also used for this purpose) or for removing a noise, that is, filtering out pixels with too small or too large values.

imgproc/threshold.qml

enumeration Type property

Extrapolation method border type:

• Threshold.BINARY if ( input(x, y) > thresh ) output(x, y) = maxVal; else output(x, y) = 0
• Threshold.BINARY_INV if ( input(x, y) > thresh ) output(x, y) = 0; else output(x, y) = maxVal
• Threshold.TRUNC if ( input(x, y) > thresh ) output(x, y) = threshold; else output(x, y) = input(x, y)
• Threshold.TOZERO if ( input(x, y) > thresh ) output(x, y) = input(x, y); else output(x, y) = 0
• Threshold.TOZERO_INV if ( input(x, y) > thresh ) output(x, y) = 0; else output(x, y) = input(x, y)
• Threshold.OTSU The function determines the optimal threshold value using the Otsu’s algorithm and uses it instead of the specified thresh

int thresh property

Threshold value

int maxVal property

Maximum value to use with the THRESH_BINARY and THRESH_BINARY_INV thresholding types.

Type thresholdType property

Maximum value to use with the THRESH_BINARY and THRESH_BINARY_INV thresholding types.

ChannelSelect type

Inherits

MatFilter

Property

int channel

Selects an image channel by its index.

imgproc/framedifference.qml

int channel property

Channel number.

StructuringElement type

Inherits

Item

Property	ElementShape shape
Property	size ksize
Property	point anchor
Property	Mat output
Property	enumeration ElementShape

Creates a structuring element of the specified size and shape for morphological operations.

imgproc/erodedilate.qml

ElementShape shape property

Element shape.

size ksize property

Size of the structuring element.

point anchor property

Anchor position within the element. The default value (-1, -1) means that the anchor is at the center. Note that only the shape of a cross-shaped element depends on the anchor position. In other cases the anchor just regulates how much the result of the morphological operation is shifted

Mat output property

Created element.

enumeration ElementShape property

Extrapolation method border type:

• StructuringElement.MORPH_RECT A rectangluar structuring element.
• StructuringElement.MORPH_ELLIPSE An elliptic structuring element, that is, a filled ellipse inscribed into the rectangle Rect(0, 0, ksize.width, ksize.height)
• StructuringElement.MORPH_CROSS A cross-shaped structuring element.

Resize type

Inherits

MatFilter

Property	Size matSize
Property	real fx
Property	real fy
Property	Interpolation interpolation
Property	enumeration Interpolation

Resizes an image.

Resizes an image according to the specified filter.

imgproc/resize.qml

Size matSize property

Size of the resized matrix. An unspecified size or a size of (0, 0) will make the element look into the fx and fy resize factors.

real fx property

Factor by which to resize on x axis.

real fy property

Factor by which to resize on y axis.

Interpolation interpolation property

Interpolation method.

enumeration Interpolation property

Interpolation method:

• Resize.INTER_NEAREST nearest neighbor interpolation
• Resize.INTER_LINEAR bilinear interpolation
• Resize.INTER_CUBIC bicubic interpolation
• Resize.INTER_AREA area-based (or super) interpolation
• Resize.INTER_LANCZOS4 Lanczos interpolation over 8x8 neighborhood
• Resize.INTER_MAX nearest neighbor interpolation*
• Resize.WARP_INVERSE_MAP nearest neighbor interpolation

Filter2D type

Converts an image with the specified kernel.

imgproc/filter2D.qml

int ddepth property

Desired depth of the destination image; if it is negative, it will be the same as input.depth(); the following combinations of src.depth() and ddepth are supported:

* input.depth() = Mat.CV_8U, ddepth = -1/Mat.CV_16S/Mat.CV_32F/Mat.CV_64F
* input.depth() = Mat.CV_16U/CV_16S, ddepth = -1/Mat.CV_32F/Mat.CV_64F
* input.depth() = Mat.CV_32F, ddepth = -1/Mat.CV_32F/Mat.CV_64F
* input.depth() = Mat.CV_64F, ddepth = -1/Mat.CV_64F

where ddepth = -1 will yield an output the same as the source.

Mat kernel property

Convolution kernel (or rather a correlation kernel), a single-channel floating point matrix.

Point anchor property

Anchor of the kernel that indicates the relative position of a filtered point within the kernel; the anchor should lie within the kernel; default value (-1,-1) means that the anchor is at the kernel center.

real delta property

Optional value added to the filtered pixels before storing them in Filter2D.output.

int borderType property

Pixel extrapolation method (see CopyMakeBorder::BorderType for details).

Dilate type

Inherits

MatFilter

Property	Mat kernel
Property	Point anchor
Property	int iterations
Property	int borderType
Property	color borderValue

Erodes an image by using a specific structuring element.

imgproc/erodedilate.qml

Mat kernel property

Structuring element used for dilation; if element=Mat(), a 3x3 rectangular structuring element is used.

Point anchor property

Position of the anchor within the element; default value (-1, -1) means that the anchor is at the element center.

int iterations property

Number of times dilation is applied.

int borderType property

Pixel extrapolation method.

See also CopyMakeBorder::BorderType

color borderValue property

Border value in case of a constant border

See also CopyMakeBorder::BorderType

Erode type

Inherits

MatFilter

Property	Mat kernel
Property	Point anchor
Property	int iterations
Property	int borderType
Property	color borderValue

Dilates an image by using a specific structuring element.

imgproc/erodedilate.qml

Mat kernel property

Structuring element used for erosion; if element=Mat() , a 3x3 rectangular structuring element is used.

Point anchor property

Position of the anchor within the element; default value (-1, -1) means that the anchor is at the element center.

int iterations property

Number of times erosion is applied.

int borderType property

Pixel extrapolation method.

See also CopyMakeBorder::BorderType

color borderValue property

Border value in case of a constant border

See also CopyMakeBorder::BorderType

CopyMakeBorder type

Inherits

MatFilter

Property	enumeration BorderType
Property	int top
Property	int bottom
Property	int left
Property	int right
Property	int borderType
Property	color color

Copies the source image into the middle of the destination image.

The areas to the left, to the right, above and below the copied source image will be filled with extrapolated pixels

imgproc/copymakeborder.qml

enumeration BorderType property

Extrapolation method border type:

• CopyMakeBorder.BORDER_REPLICATE
• CopyMakeBorder.BORDER_CONSTANT
• CopyMakeBorder.BORDER_REFLECT
• CopyMakeBorder.BORDER_WRAP
• CopyMakeBorder.BORDER_REFLECT_101
• CopyMakeBorder.BORDER_TRANSPARENT
• CopyMakeBorder.BORDER_DEFAULT
• CopyMakeBorder.BORDER_ISOLATED

int top property

Property specifying how many pixels in the top direction from the source image rectangle to extrapolate.

int bottom property

Property specifying how many pixels in the bottom direction from the source image rectangle to extrapolate.

int left property

Property specifying how many pixels in the left direction from the source image rectangle to extrapolate.

int right property

Property specifying how many pixels in the right direction from the source image rectangle to extrapolate.

int borderType property

Border type. See also CopyMakeBorder::BorderType

color color property

Border value if borderType==CopyMakeBorder.BORDER_CONSTANT. See also CopyMakeBorder::BorderType

Draw type

Inherits

QtQObject

Method	line(WritableMat m, Point p1, Point p2, Color color, int thickness, int lineType, int shift)
Method	rectangle(WritableMat m, Point p1, Point p2, Color color, int thickness, int lineType, int shift)
Method	circle(WritableMat m, Point center, int radius, Color color, int thickness, int lineType, int shift)
Method	ellipse(WritableMat m, Point center, Size axes, real angle, real startAngle, real endAngle, Color color, int thickness, int lineType, int shift)
Method	fillPoly(WritableMat m, variant points, Color color, int lineType, int shift, Point offset)

Singleton. Provides matrix drawing operations.

Provides the basic set of functions needed in order to draw on a matrix.

imgproc/drawing.qml

line(WritableMat m, Point p1, Point p2, Color color, int thickness, int lineType, int shift) method

Draw a line from point p1 to point p2 of a specified color and thickness. The lineType can be 4 ( 4-connected line ), 8 (8-connected line, also the default) and -1 (antialiased line). The shift is the number of fractional bits in the point coordinates.

rectangle(WritableMat m, Point p1, Point p2, Color color, int thickness, int lineType, int shift) method

Draw a rectangle from point p1 to point p2 of a specified color and thickness. The lineType can be 4 ( 4-connected line ), 8 (8-connected line, also the default) and -1 (antialiased line). The shift is the number of fractional bits in the point coordinates.

circle(WritableMat m, Point center, int radius, Color color, int thickness, int lineType, int shift) method

Draw a circle by specifying its center point, radius, color and thickness. For the lineType and shift, see the lin method.

ellipse(WritableMat m, Point center, Size axes, real angle, real startAngle, real endAngle, Color color, int thickness, int lineType, int shift) method

Draw an ellipse in the center point, with its axes (half of the size of the ellipse main axes), rotation angle in degrees, startAngle and endAngle of the elliptic arc in degrees and color. For the lineType and shift see the line method.

Draws an ellipse.

fillPoly(WritableMat m, variant points, Color color, int lineType, int shift, Point offset) method

Fills the area bounded by one or more polygons. The points is the array of polygons where each polygon is represented by an array of points, the color is the polygons color, the [lineType] is the type of the polygon boundaries and the shift is the number of fractional bits in the vertex coordinates. The offset is an optional offset of all points of the contours.

GetPerspectiveTransform type

Inherits

MatFilter

Calculates a perspective transform from four pairs of the corresponding points.

Parameters:

• src – Coordinates of quadrangle vertices in the source image.
• dst – Coordinates of the corresponding quadrangle vertices in the destination image.

See also GetPerspectiveTransform

warpPerspective type

Inherits

MatFilter

Applies a perspective transformation to an image.

Parameters:

• src – input image.
• dst – output image that has the size dsize and the same type as src .
• M – 3 X 3 transformation matrix.
• dsize – size of the output image.
• flags – combination of interpolation methods (INTER_LINEAR or INTER_NEAREST) and the optional flag WARP_INVERSE_MAP, that sets M as the inverse transformation ( dst → src ).
• borderMode – pixel extrapolation method (BORDER_CONSTANT or BORDER_REPLICATE).
• borderValue – value used in case of a constant border; by default, it equals 0.

See also warpPerspective

QCachedWarpPerspective type

Inherits

MatFilter

Applies a perspective transformation to an image.

Caches the transformation matrix when initialising, so it's faster and recommended to use for videos.

• src – input image.
• dst – output image that has the size dsize and the same type as src .
• M – 3 X 3 transformation matrix.
• dsize – size of the output image.

See also warpPerspective