ortho2 to plot differences between a predicted binary
image and the assumed ground truth (roi).
ortho_diff(img, pred, roi, xyz = NULL, cols = c("#56B4E9", "#D55E00", "#009E73"), levels = c("False Negative", "False Positive", "True Positive"), addlegend = TRUE, center = TRUE, leg.cex = 1.5, ...)ortho2xyz on roi. Disregarded if xyz is
not NULLortho2ortho2