I’ve been using solvepnp and had a question regarding the coordinate system. So, basically I know where the solution ‘should’ be, but I’m unsure about how the coordinate system is oriented. I’ve read that opencv has xyz positive, going right down away. So say if I have the original Y value and try to plot it, would this actually be a -Y I should be plotting? I’ve got two images with a -Y value vs the original Y value. No matter how I look at it, the -Y seems to be the correct solution. I’ve plotted both +Y and -Y values, with my object points below.

Original Y value

Negative Y value

And then I’ve also done the reprojection of my objpoints, and both solutions for +/- Y.

Blue - imgpoints

Red - reprojection of objpoints

Black - center of my image (640x480)

Gray - reprojection of +Y valued solution

Orange- reprojection of -Y valued solution

The error for both are below, and the error for my reprojected objpoints and imgpoints is <1

Or because the coordinate system is xyz positive going right down away, should I be plotting my world points with a -Y, to match the orientation of the solvepnp solution?