Random Forest for Hand Pose Estimation from Single Depth Image

Introduction

This program has a Random Forest containing number of Trees who can be trained by training data and make prediction on test data. The Random Forest will then collect the results of all the trees and make the final prediction.

This program is an implementation of paper: Chi Xu, Ashwin Nanjappa, Xiaowei Zhang, Li Cheng. Estimate Hand Poses Efficientlyfrom Single Depth Images. In In International Journal of Computer Vision (IJCV), 2015.

We have implemented the 'baseline-M' version and the 'dynamical weight at leaf nodes' version.

The baseline-M is a normal random forest that can be changed and adapted for other general problem sovling.

Platform

• Ubuntu14.04 or other common Linux version.
• Mac and Windows is possible, but may need some configuration by yourself.
• Note you also need to have the Prerequests on your platform.

Directory

.    
CMakeList.txt  *For Cmake
Makefile    *For compile time use, sepcifing the compile rules.
README.md   *This file.
common.h
...         *The source files and the makefile.
main.cpp
InputData/  *Stores input data `.csv`.
OutputData/  *Stores output data from program `.csv`.
ExampleInput/  *Stores some small examples of input data file.

Prerequest

• g++ * The C++ compiler, or you can use anything equvalent.
• Armadillo-7.400.2 * A linear algebra C++ open library.

How to install the prerequests? First download the armdillo-7.400.2.zip from this link, then uppack it. Alternatively, you could also refers to official website of Armdillo install openCV at openCV official user guide

$ sudo apt-get update
$ sudo apt-get install g++
$ sudo apt-get install cmake
$ sudo apt-get install libblas-dev liblapack-dev
$ cd /YourDirectory/armdillo-7.400.2
$ cmake .
$ make
$ sudo make install

Finish. Now you have the compiler and the linear algebra library. Notice above command lines are not tested, so not ensure work. For detail information about Armdillo, please refer to its RAEDME.txt, in line 125.

We need Armadillo to do some matrix calculation such as COV() and DET(), Armadillo can also be installed on Windows if you like.

Compile

$ cd /YourDirectory/HandPoseEstimation/
$ cmake .
$ make

After the make, you should see some files like .o, .gch and excutable run.out. If failed during in make, please check you if your prerequests are successfully installed.

Run

$ ./HandPoseEstimation
$ d

for debug mode. (without test on test data)

or

$ ./HandPoseEstimation
$ r 

for real time mode. (with output of test data result)

When you are running the program, it will ask you which mode to choose, for now, just choose debug mode.

Notice: If you experience 'segmentation falt‘ during your running, please first check the 'feaNum','labelNum' and 'trainExampleNum' at 'common.h'.

Program Input and Output

This program does not input from the raw files like .shand, .skdepth or skdepth.cropping. Instead this program takes a single '.csv' file as its input, which stores all the training examples.

The training Data in .csv format can be downloaded at: this link where value0, value1, ... is the pixel value of our depth image, so there should be 90*60 values,and the label0, label1, ... is the hand joints postion value, so there should be 20*3 labels.

In both debug and real-time mode of this program at running time, the program will output two files under folder HandPoseEstimation/OutputData:

• resultRaw.csv
• result.csv

And with postfix of Debug or Real, imples which mode has been chosen. In debug mode where we have only training data input, we can also output prediction results because we split the training data into two part in the debug mode, 70% for training and 30% for testing.

Parameter Settings

There are some parameters like number of threads, number of features, number of labels are in the source file common.h, specifing by #define. Just edit them and save if you need.

Please set the NUMTHREAD equals to the cores of your computer.

Parameters that can be set in 'main.cpp':

1. Threasholds for the trees at training time. See a, b, c in the code.
2. Number of trees in the forest. See treeNum in the code.
3. The ratio of training data and test data at debug mode. See code trainData.split().
4. Input and output file names can be found in main.cpp.

Other parameters: If you want to change the percentage of random data assigned to each tree, refer to RandomForest.cpp->RandomForest::run()->generateRandomData(0.6).

Known Bugs

This is just a prototype, below are a list that the way I used is not same with the paper.

1. I randomly select 60% examples for a tree rather than randomly select them at each spliting node time.
2. In the RandomForest, the vote is done by just calculting the average value of all the results.
3. At prediction time, just goes down along the tree by seeing if the corresponing feature value of the example is bigger then the split value at the node. When reach leaf, return the average value of labels in the leaf.
4. For randomly select features at a node, I randomly select sqrt(features.size()).

About CS5340

This Hand Pose Estimation is a course project of NUS School of Computing CS5340 Uncertainty modelling in AI Fall 2016.

Useful books:

• Probabilistic Graphical Models : Principles and Techniques Daphne Koller and Nir Friedman

• An Introduction to Probabilistic Graphical Models M. Jordan

• Deep Learning Online Book

• Graphical models, exponential families, and variational inference

• Probabilistic Reasoning in Intelligent Systems: Networks of Plausible Inference

Team member

• Liu Zhendong - Tony
• Yang Xuan - Yancy
• Huang Mengying - Molly

Reference

1. Chi Xu, Ashwin Nanjappa, Xiaowei Zhang, Li Cheng. "Estimate Hand Poses Efficiently from Single Depth Images". In In International Journal of Computer Vision (IJCV), 2015.
2. Conrad Sanderson and Ryan Curtin. Armadillo: a template-based C++ library for linear algebra. Journal of Open Source Software, Vol. 1, pp. 26, 2016.