Gaze interface: retrieving 3D fixation point using monocular approach

[valeriosperati]

Please, I need some clarification about the issue object.
In icub simulator (icub_SIM), I'm successfully using lookAtMonoPixel function in order to gaze a ball on a table with right cam . The ball has coordinates x=0, y= 0.7; z=1.5 in world reference frame (these should be about x=-1.5, y= 0, z= 0.10 in robot reference frame).
Once the gaze is performed, the object is correctly located in the center of the image, about 160, 120 pixels.

Now I would like to retrieve the 3D point of the object.
As I understand here, "geometry of pixels" paragraph, I need to use the function get3DPointOnPlane(). Maybe I misunderstood the meaning of function arguments: my code is

Vector 3Dpoint;
Vector px(2);
px[0] = 160;
px[1] = 120;

Vector plane(4);
plane[0]=0;
plane[1]=0;
plane[2]=1;
plane[3]= 0.1;  // I guess this is the z of ball in robot reference frame

//using right cam
igaze->get3DPointOnPlane(1, px, plane, 3DPoint);

I would expect 3DPoint is about [-1.5, 0, 0.1], but I obtain something like [-3, 0, -0.1]. What Am I missing?

[vicentepedro]

Hi @valeriosperati,

You can check here
in the first code box.

in your code it should be:
plane[3]= -0.1;
since you are solving the plane equation:
ax+by+cz+d=0

the equation will become:
z-0.1=0 <=> z=0.1

[valeriosperati]

Ops! I completely missed the minus 1! Thanks a lot :) it works