OpenCV  4.1.1 Open Source Computer Vision
cv::line_descriptor::KeyLine Struct Reference

A class to represent a line. More...

#include <opencv2/line_descriptor/descriptor.hpp>

## Public Member Functions

KeyLine ()

Point2f getEndPoint () const

Point2f getEndPointInOctave () const

Point2f getStartPoint () const

Point2f getStartPointInOctave () const

## Public Attributes

float angle

int class_id

float endPointX

float endPointY

float ePointInOctaveX

float ePointInOctaveY

float lineLength

int numOfPixels

int octave

Point2f pt

float response

float size

float sPointInOctaveX

float sPointInOctaveY

float startPointX

float startPointY

## Detailed Description

A class to represent a line.

As aformentioned, it is been necessary to design a class that fully stores the information needed to characterize completely a line and plot it on image it was extracted from, when required.

KeyLine* class has been created for such goal; it is mainly inspired to Feature2d's KeyPoint class, since KeyLine shares some of KeyPoint's fields, even if a part of them assumes a different meaning, when speaking about lines. In particular:

• the class_id field is used to gather lines extracted from different octaves which refer to same line inside original image (such lines and the one they represent in original image share the same class_id value)
• the angle field represents line's slope with respect to (positive) X axis
• the pt field represents line's midpoint
• the response field is computed as the ratio between the line's length and maximum between image's width and height
• the size field is the area of the smallest rectangle containing line

Apart from fields inspired to KeyPoint class, KeyLines stores information about extremes of line in original image and in octave it was extracted from, about line's length and number of pixels it covers.

## § KeyLine()

 cv::line_descriptor::KeyLine::KeyLine ( )
inline

constructor

## § getEndPoint()

 Point2f cv::line_descriptor::KeyLine::getEndPoint ( ) const
inline

Returns the end point of the line in the original image

## § getEndPointInOctave()

 Point2f cv::line_descriptor::KeyLine::getEndPointInOctave ( ) const
inline

Returns the end point of the line in the octave it was extracted from

## § getStartPoint()

 Point2f cv::line_descriptor::KeyLine::getStartPoint ( ) const
inline

Returns the start point of the line in the original image

## § getStartPointInOctave()

 Point2f cv::line_descriptor::KeyLine::getStartPointInOctave ( ) const
inline

Returns the start point of the line in the octave it was extracted from

## § angle

 float cv::line_descriptor::KeyLine::angle

orientation of the line

## § class_id

 int cv::line_descriptor::KeyLine::class_id

object ID, that can be used to cluster keylines by the line they represent

## § endPointX

 float cv::line_descriptor::KeyLine::endPointX

## § endPointY

 float cv::line_descriptor::KeyLine::endPointY

## § ePointInOctaveX

 float cv::line_descriptor::KeyLine::ePointInOctaveX

## § ePointInOctaveY

 float cv::line_descriptor::KeyLine::ePointInOctaveY

## § lineLength

 float cv::line_descriptor::KeyLine::lineLength

the length of line

## § numOfPixels

 int cv::line_descriptor::KeyLine::numOfPixels

number of pixels covered by the line

## § octave

 int cv::line_descriptor::KeyLine::octave

octave (pyramid layer), from which the keyline has been extracted

## § pt

 Point2f cv::line_descriptor::KeyLine::pt

coordinates of the middlepoint

## § response

 float cv::line_descriptor::KeyLine::response

the response, by which the strongest keylines have been selected. It's represented by the ratio between line's length and maximum between image's width and height

## § size

 float cv::line_descriptor::KeyLine::size

minimum area containing line

## § sPointInOctaveX

 float cv::line_descriptor::KeyLine::sPointInOctaveX

line's extremes in image it was extracted from

## § sPointInOctaveY

 float cv::line_descriptor::KeyLine::sPointInOctaveY

## § startPointX

 float cv::line_descriptor::KeyLine::startPointX

lines's extremes in original image

## § startPointY

 float cv::line_descriptor::KeyLine::startPointY

The documentation for this struct was generated from the following file: