Update README.md

README.md

@@ -1,5 +1,5 @@
 # NeRF++
-Codebase for arXiv preprint: 
+Codebase for arXiv preprint "NeRF++: Analyzing and Improving Neural Radiance Fields"
 * Work with 360 capture of large-scale unbounded scenes.
 * Support multi-gpu training and inference with PyTorch DistributedDataParallel (DDP). 
 * Optimize per-image autoexposure (**experimental feature**).
@@ -10,6 +10,7 @@ Codebase for arXiv preprint:
 * Data format. 
     * Each scene consists of 3 splits: train/test/validation. 
     * Intrinsics and poses are stored as flattened 4x4 matrices (row-major).
+    * Pixel coordinate of an image's upper-left corner is (column, row)=(0, 0). 
     * Poses are camera-to-world, not world-to-camera transformations.
     * Opencv camera coordinate system is adopted, i.e., x--->right, y--->down, z--->scene.
     * To convert camera poses between Opencv and Opengl conventions, the following snippet can be used for both Opengl2Opencv and Opencv2Opengl.