halcon 机器视觉 calibration to world

? 2003-2009 MVTec Software GmbH

Camera Calibration

To World Coordinates: Points

Task

n Convert pixel (image) coordinates into world coordinates

Operator

n image_points_to_world_plane

Parameters

n CamParam: Camera parameters

n Pose: Pose of the measurement plane

n Rows: Row coordinate(s) in image coordinates

n Columns: Column coordinate(s) in image coordinates

n Unit: Desired unit as string (e.g., 'm')

n Sx: X value(s) in world coordinates

n Sy: Y value(s) in world coordinates

distance_pp (Sy[0], Sx[0], Sy[1], Sx[1], Width)

gen_measure_arc(Row,Column,Rad,0,rad(360),20,Width,Height,

'nearest_neighbor',MeasureHandle)

measure_pairs(Image,MeasureHandle,1,30,'positive','all',RowEd ColumnEdgeFirst,_,RowEdgeSecond,ColumnEdgeSecond,_,_,_)To World Coordinates: Measure Arc

Transform the center of the circle into world coordinates

Transform one point on the circle into world coordinates to calculate the

RowEdgeFirst[i],ColumnEdgeFirst[i],'m',

RowEdgeSecond[i],ColumnEdgeSecond[i],'m',

angle_ll(YWorld,XWorld,YFirstWorld,XFirstWorld,YWorld,XWorld,

(Image, Edges, 'lanser2',

ClosedEdge,

'closed', 0, 1, 0, 0)

(ClosedEdge, ContoursWorld,

CamPar, Pose, 'm')

Area, Row, Column,Original contours After grouping

Edges, 'lanser2', 0.5, 22, 30)

(Edges, ContoursWorld, CamPar, Pose, 'm') (ContoursWorld, SelectedContours, 'length',

Polygons, 'ramer', 2)

(Polygons, Contours, 'polygon', 1, 5)

(Contours, RegressContours, 'no', 1)

(RegressContours, UnionContours, 5, 0.5,

(UnionContours, 'tukey', -1, 0, 5, 2, RowBegin, ColBegin, RowEnd, ColEnd, Nr, Nc, Dist)To World Coordinates: Regions Calculate calibrated features of regions

Example program to convert world coordinates to image coordinates

Constant y-values Constant x-values The orientation of the calibration plate determines the orientation of the

Constant x-values

Constant y-values Camera Alignment Slant -38°

Rotation -21Interpretation of the last three values of the pose Assuming that the calibration plate is perfectly aligned with the object space

n Slant

n > 0 Camera is looking from the top n < 0 Camera is looking from the bottom n Pan

Coordinate System

Size of a pixel:

n Each projected pixel has a different size

n The size has to be determined for each pixel separately

for x := 0 to 639 by 1for y := 0 to 479 by 1