# HG changeset patch
# User Nicolas Saunier <nicolas.saunier@polymtl.ca>
# Date 1639769205 18000
# Node ID 2f89dc3d99e5f31ec9d5f92d289eb1b1bb4bf5c0
# Parent  c1766bb5076c74fab15d0020d4dda694a1343bca
clarification of worldToImageProject method

diff -r c1766bb5076c -r 2f89dc3d99e5 trafficintelligence/cvutils.py
--- a/trafficintelligence/cvutils.py	Mon Oct 18 11:42:53 2021 -0400
+++ b/trafficintelligence/cvutils.py	Fri Dec 17 14:26:45 2021 -0500
@@ -569,9 +569,11 @@
         return homographyProject(points, homography)
 
 def worldToImageProject(points, intrinsicCameraMatrix = None, distortionCoefficients = None, homography = None):
-    '''Projects points (2xN array) from image (video) space to world space
+    '''Projects points (2xN array) from world space to image (video) space
     1. through undistorting if provided by intrinsic camera matrix and distortion coefficients
-    2. through homograph projection (from ideal point (no camera) to world)'''
+    2. through homograph projection (from ideal point (no camera) to world)
+
+    Warning: this usually means to invert the homography if computer from image (ideal point) to world space, eg using numpy.linalg.inv'''
     if points.shape[0] != 2:
         raise Exception('points of dimension {}'.format(points.shape))