Viola–Jones object detection[1][7]

包含下列四個步驟


  1. 1. Haar Feature Selection
  2. 2. Creating an Integral Image
  3. 3. Adaboost Training
  4. 4. Cascading Classifiers


MATLAB File Exchange有Viola-Jones的改良版,

主要增加Haar Like Feature的核心(kernel)選擇不同

請先下載

Objects/Faces Detection Toolbox

>> mex -setup
 

Welcome to mex -setup.  This utility will help you set up  
a default compiler.  For a list of supported compilers, see  
http://www.mathworks.com/support/compilers/R2012b/win64.html 
  
Please choose your compiler for building MEX-files: 
  
Would you like mex to locate installed compilers [y]/n? y
  
Select a compiler: 
[1] Microsoft Visual C++ 2010 in C:\Program Files (x86)\Microsoft Visual Studio 10.0 
  
[0] None 
  
Compiler: 1
  
Please verify your choices: 
  
Compiler: Microsoft Visual C++ 2010  
Location: C:\Program Files (x86)\Microsoft Visual Studio 10.0 
  
 Are these correct [y]/n? y

--------------------------------------------------------------------

>> setup_fdt

Unzipping negatives picts ...
 Compile mex files ...
 compiling chlbp
 compiling chlbp_adaboost_binary_train_cascade
compiling chlbp_adaboost_binary_predict_cascade
 compiling chlbp_gentleboost_binary_train_cascade
 compiling chlbp_gentleboost_binary_predict_cascade
 compiling detector_haar
 compiling detector_mblbp
 compiling eval_chlbp
 compiling eval_haar
 compiling eval_haar_subwindow
 compiling eval_mblbp
 compiling eval_mblbp_subwindows
 compiling haar
 compiling haar_ada_weaklearner
 compiling haar_adaboost_binary_train_cascade
 compiling haar_adaboost_binary_predict_cascade
 compiling haar_featlist
 compiling haar_gentle_weaklearner
 compiling haar_gentleboost_binary_train_cascade
 compiling haar_gentleboost_binary_predict_cascade
 compiling haar_scale
 compiling imresize
 compiling area
 compiling homkermap
 compiling homkertable
 compiling eval_hmblbp_spyr_subwindow
 compiling detector_mlhmslbp_spyr
 compiling eval_hmblgp_spyr_subwindow
compiling detector_mlhmslgp_spyr
 compiling mblbp
 compiling mblbp_ada_weaklearner
 compiling mblbp_adaboost_binary_train_cascade
 compiling mblbp_adaboost_binary_predict_cascade
 compiling mblbp_featlist
 compiling mblbp_gentle_weaklearner
 compiling mblbp_gentleboost_binary_train_cascade
 compiling mblbp_gentleboost_binary_predict_cascade
 compiling rgb2gray
 compiling fast_rotate
 compiling haar_ada_weaklearner_memory
 compiling haar_adaboost_binary_predict_cascade_memory
 compiling haar_adaboost_binary_train_cascade_memory
 compiling haar_gentle_weaklearner_memory
 compiling haar_gentleboost_binary_predict_cascade_memory
 compiling haar_gentleboost_binary_train_cascade_memory
 compiling int8tosparse
 compiling fast_haar_ada_weaklearner
 compiling fast_haar_adaboost_binary_train_cascade
 compiling train_dense
 Failed to compile mex-files, unzip precompiled mex64
 Error using checkfilename>validateFilename (line 166)
 Function UNZIP was unable to find file ''mexw64.zip''.
 
Error in checkfilename (line 50)
 [fullfilename, fid] = validateFilename( ...
 
Error in parseUnArchiveInputs (line 82)
 [archiveFilename, url] = checkfilename(archiveFilename, validExtensions, ...
 
Error in unzip (line 58)
 [zipFilename, outputDir, url, urlFilename] = parseUnArchiveInputs( ...
 
Error in setup_fdt (line 80)
             unzip('mexw64.zip' , conf.path);

--------------------------------------------------------------------

demo_haar.m

clear, close all,clc,drawnow
load viola_24x24

image

載入後觀察X, y毫無頭緒,

根據兩者維度推測, 嘗試 imshow(X(:,:,1))

原來裡面塞了一堆faces

image

imshow(X(:,:,2))

image

>> plot(y)

各位看了這個下面這張圖想必猜得出來1~4915筆前的資料是一群,

4916~12788筆的資料是另一群

image

>> imshow(X(:,:,4917))

真的是non-face, BINGO!!!

image

特徵擷取

A: Dims=1x2, kernelA=[-1, 1];

B: Dims=2x1, kernelB=[1; –1];

C: Dims=1x3, kernelC=[-1, 1, –1];

D: Dims=2x2, kernelD=[-1, 1; 1 –1];

image


image

image
private static int CalCounts(int frameSize)
  {
      const int features = 5;
      // All five feature types:
      // { width, height} for each set
      int[,] feature = new int[features, 2]{ { 2, 1 }, { 1, 2 }, { 3, 1 }, { 1, 3 }, { 2, 2 } };  
 
      int count = 0;
      int i, sizeX, sizeY, x, y, width, height;
      // Each feature:
      for (i = 0; i < features; i++) {
          sizeX = feature[i,0];
          sizeY = feature[i,1];
      
          // Each position:
          for (x = 0; x <= frameSize-sizeX; x++) {
              for (y = 0; y <= frameSize-sizeY; y++) {
              // Each size fitting within the frameSize:
                  for (width = sizeX; width <= frameSize-x; width+=sizeX) {
                      for (height = sizeY; height <= frameSize-y; height+=sizeY) {
                      count++;
                      }
                  }
              }
          }
      }
      return count;
  }

Integral Image

image

image

An Extended Set of Haar-like Features for Rapid Object Detection[6]

增加特徵提高準確率!

特徵長度加總竟然比Viola-Jones還少 117, 941 < 162,336

image


image

-----------------------------------------------------------------------------------





參考資料

1. Rapid Object Detection using a Boosted Cascade of Simple Features

2. integral

3. MATLAB Objects/Faces Detection Toolbox

4. MATLAB traincascadeobjectdetector

5. Viola-Jones' face detection claims 180k features

6. An Extended Set of Haar-like Features for Rapid Object Detection

7. Viola–Jones object detection framework


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