Added binary PLY support and support for variable CSV column formats

Author: dcyoung

Assets/Scripts/CSVReader.cs

@@ -26,6 +26,11 @@ public static List<Vector4> ReadPoints(string file)
             if (numPoints <= 0)
                 return null;
 
+            // check if the .csv contains a column for scan index
+            string header = lines[0];
+            int offset = header.Contains("SCAN_INDEX") ? 1 : 0;
+            bool bContainsSigStrength = header.Contains("SIGNAL_STRENGTH");
+
             List<Vector4> points = new List<Vector4>();
             float x, y, z, normalizedSignalStrength;
             for (int i = 0; i < numPoints; i++)
@@ -35,11 +40,12 @@ public static List<Vector4> ReadPoints(string file)
 
                 // Read the position
                 // convert from the centimeters to meters, and flip z and y (RHS to LHS)
-                x = 0.01f * float.Parse(row[1]);
-                z = 0.01f * float.Parse(row[2]);
-                y = 0.01f * float.Parse(row[3]);
+                x = 0.01f * float.Parse(row[0 + offset]);
+                z = 0.01f * float.Parse(row[1 + offset]);
+                y = 0.01f * float.Parse(row[2 + offset]);
+
                 // Read the signal strength and normalize it. ie: [0 : 254] => [0.0f : 1.0f]
-                normalizedSignalStrength = float.Parse(row[4]) / 254.0f;
+                normalizedSignalStrength = bContainsSigStrength ? (float.Parse(row[3 + offset]) / 254.0f) : 0.75f;
 
                 // Package the position and signal strength into a single 4 element vector
                 points.Add(new Vector4(x, y, z, normalizedSignalStrength));

Assets/Scripts/PLYReader.cs

@@ -0,0 +1,92 @@
+using System;
+using System.IO;
+using System.Collections;
+using System.Collections.Generic;
+using System.Text.RegularExpressions;
+using UnityEngine;
+
+/// <summary>
+/// Naively parses a ply file of an expected structure into an array of Vector4 objects.
+/// Expected structure is vertices with following attributes ONLY: float x, float y, float z, u_char signal_strength
+/// Each Vector4 represents a point, where the x,y,z components are the position and the w component holds normalized signal strength.
+/// Handles the conversion from centimeters to meters.
+/// Handles the conversion from right handed coordinates where z is up, to unity's left handed coordinates where y is up.
+/// </summary>
+public class PLYReader
+{
+    public static List<Vector4> ReadPoints(string file)
+    {
+        // Check file exists
+        if (!File.Exists(file))
+        {
+            return new List<Vector4>();
+        }
+
+        try
+        {
+            // Interpret File
+            using (BinaryReader reader = new BinaryReader(File.Open(file, FileMode.Open)))
+            {
+                int fileLength = (int)reader.BaseStream.Length;
+                string buildingLine = "";
+                int vertexCount = 0;
+                int charSize = sizeof(char);
+
+                // read the header
+                int numRead = 0;
+                while ((numRead += charSize) < fileLength)
+                {
+                    char nextChar = reader.ReadChar();
+                    if (nextChar == '\n')
+                    {
+                        if (buildingLine.Contains("end_header"))
+                        {
+                            break;
+                        }
+                        else if (buildingLine.Contains("element vertex"))
+                        {
+                            string[] array = Regex.Split(buildingLine, @"\s+");
+                            if (array.Length - 2 > 0)
+                            {
+                                int target = Array.IndexOf(array, "vertex") + 1;
+                                vertexCount = Convert.ToInt32(array[target]);
+                                buildingLine = "";
+                            }
+                            else
+                            {
+                                return new List<Vector4>();
+                            }
+                        }
+                    }
+                    else
+                    {
+                        buildingLine += nextChar;
+                    }
+                }
+                
+                // Read the vertices
+                List<Vector4> points = new List<Vector4>();
+                float x, y, z, normalizedSignalStrength;
+                for (int i = 0; i < vertexCount; i++)
+                {
+                    // Read the position
+                    // convert from the centimeters to meters, and flip z and y (RHS to LHS)
+                    x = 0.01f * reader.ReadSingle();
+                    z = 0.01f * reader.ReadSingle();
+                    y = 0.01f * reader.ReadSingle();
+
+                    // Read the signal strength and normalize it. ie: [0 : 254] => [0.0f : 1.0f]
+                    normalizedSignalStrength = 1.0f * reader.ReadByte() / 254.0f;
+
+                    // Package the position and signal strength into a single 4 element vector
+                    points.Add(new Vector4(x, y, z, normalizedSignalStrength));
+                }
+                return points;
+            }
+        }
+        catch (Exception e)
+        {
+            return new List<Vector4>();
+        }
+    }
+}

Assets/Scripts/PLYReader.cs.meta

@@ -28,17 +28,36 @@ public class PointCloudGenerator : MonoBehaviour
     void Awake()
     {
         // Open a native file dialog, so the user can specify the file location
-        SFB.ExtensionFilter[] extensions = new[] { new ExtensionFilter("Point Cloud Files", "csv") };
+        SFB.ExtensionFilter[] extensions = new[] { new ExtensionFilter("Point Cloud Files", "csv", "ply") };
         string[] paths = StandaloneFileBrowser.OpenFilePanel("Open File", "", extensions, false);
         if (paths.Length < 1)
         {
-            print("Error: Please specify a CSV file.");
+            print("Error: Please specify a properly formatted CSV or binary PLY file.");
             Application.Quit();
             return;
         }
 
+        string filePath = paths[0];
+        string[] parts = filePath.Split('.');
+        string extension = parts[parts.Length - 1];
+
         // Read the points from the file
-        data = CSVReader.ReadPoints(paths[0]);
+        switch (extension)
+        {
+            case "csv":
+            case "CSV":
+                data = CSVReader.ReadPoints(filePath);
+                break;
+            case "ply":
+            case "PLY":
+                data = PLYReader.ReadPoints(filePath);
+                break;
+            default:
+                print("Error: Please specify a properly formatted CSV or binary PLY file.");
+                Application.Quit();
+                return;
+        }
+
         numPoints = data.Count;
         if (numPoints <= 0)
         {
@@ -68,7 +87,7 @@ void Awake()
             for (int j = 0; j < numPointsPerCloud; j++)
             {
                 // normalzied signal strength stored in the 4th component of the vector
-                normalizedSignalStrength[j] = data[offset + j].w;
+                normalizedSignalStrength[j] = data[offset + j].w * 0.3f;
 
                 // position stored in the first 3 elements of the vector (conversion handled by implicit cast)
                 positions[j] = data[offset + j];

Assets/Scripts/PointCloudGenerator.cs

@@ -0,0 +1,5 @@
+# Changelog
+
+## 9/13/2017
+- Added ability to read binary `.ply` files.
+- Added support for `.csv` files with or without `SCAN_INDEX` and `SIGNAL_STRENGTH` columns.

CHANGELOG.md

@@ -14,8 +14,9 @@ Main Viewer                |  Miniature Viewer
 ### Quickstart
 - Run the executable `Point_Cloud_Viewer.exe` or `Miniature_Point_Cloud_Viewer.exe`.
 - Once the app loads, a file browser should open automatically. 
-- Select a CSV pointcloud file, with the expected format.
-- Wait for the application to parse the file and render the points.
+- Select a PLY (binary) or CSV pointcloud file, with the [expected format](#compatible-file-format).
+- Wait for the application to parse the file and render the points. 
+> **Note:** binary `.ply` files parse significantly faster than `.csv`
 - For the main viewer, use `Q` & `E` to adjust the vertical position of the point cloud so the camera appears to be at head height, and the floor in the scan matches the ground plane. Then walk around inside the scan.
 - For the miniature viewer, experiment with the transform controls listed below to view the diorama.
 - To exit the application and close the executable, press `ESC`.
@@ -36,21 +37,26 @@ Main Viewer                |  Miniature Viewer
 - The scan will not appear until you put on the headset.
 
 ### Compatible file format
-Only files with the expected format will open correctly. Attempting to open unexpected files will terminate the unity application. The application expects `.csv` files downloaded from the `sweep-3d-scanner` or exported from the `Sweep Visualizer` desktop application. 
+Only files with the expected format will open correctly. Attempting to open unexpected files will terminate the unity application. The application expects either `.csv` or `.ply (binary)` files downloaded from the `sweep-3d-scanner` or exported from the `Sweep Visualizer` desktop application. 
 
-If you want to convert custom data to make a compatible file, create a CSV file with the following format:
+If you want to convert custom data to make a compatible file, create a CSV file where the first line is a header, subsequent rows represent points, and the first 3 columns are `X`, `Y` and `Z`. Optionally, you can include a 4th column called `SIGNAL_STRENGTH`. Example file contents shown below.
 ```csv
-SCAN_INDEX,X,Y,Z,SIGNAL_STRENGTH
-0,6.7,-124.2,-71.3,183
-0,6.7,-125.4,-69.2,187
+X,Y,Z
+6.7,-124.2,-71.3
+6.7,-125.4,-69.2
+...
+
+or 
+
+X,Y,Z,SIGNAL_STRENGTH
+6.7,-124.2,-71.3,199
+6.7,-125.4,-69.2,199
 ...
 ```
 
-- SCAN_INDEX: is the index of the 2D slice of a 3D scan. This is a reference to the data acquisition process used by the 3D scanner, and is NOT used by the unity viewer. If you are making a file from scratch, simply use 0 for every entry.
 - X,Y,Z: Integer or floating point values representing the x, y and z coordinates for each point. Units are in cm. Assumes a right handed coordinate system, where z is up. Note: this is NOT the same as unity's coordinate system, which is left handed with y up.
 - SIGNAL_STRENGTH: integer value between [0:254] indicating strength/confidence in the sensor reading. Higher values are stronger readings, lower values are weaker readings. The color of points in the viewer are determined by this value, by mapping the range [0:254] to the entirety of the HUE spectrum in HSV color space. If you are generating a custom file, and you do NOT have signal strength values for your data points, simply use the same value for every point. 
 
-
 ## Unity Project
 ### Packages/Dependencies
 - `Standard Assets/Characters`: provides first person character controller
@@ -66,6 +72,9 @@ SCAN_INDEX,X,Y,Z,SIGNAL_STRENGTH
 - `Scripts/CSVReader`: 
   - Naively parses a csv file of the expected structure into an array of `Vector4` objects. 
   - Each `Vector4` represents a point, where the first 3 elements (x,y,z) are position, and the 4th (w) is normalized signal strength.
+- `Scripts/PLYReader`: 
+  - Naively parses a ply (binary) file of the expected structure into an array of `Vector4` objects. 
+  - Each `Vector4` represents a point, where the first 3 elements (x,y,z) are position, and the 4th (w) is normalized signal strength.
 - `Scripts/PointCloudGenerator`: 
   - Requests the user select a `.csv` file.
   - Reads the points from the file.