Bag of Features with SURF and ID3 and KNN

[hhmm...@gmail.com]

Hi
I am making program for face recognition using Accord.net.
the steps are as follow
1. create Excel sheet containing the location of image in PC and its name and the ID number of each individual.
I used 14 image for each individual for training phase.
2. Extract bag of visual word for each image by BOW (50 or more clusters) in accord.net and consider them as input for learning phase
3. the output is the ID number of each individual
4. learn ID3 or KNN (input,output)
5. insert Test dataset 5 image for each individual and make prediction for each test image and save results in new excel sheet

Now, I have two problems:
1. the accuracy for recognition rate is very low
for decision tree ID3 it is 26% (51 individual,703 training image,292 test image, 14 image for each individual) and the time is 724404 ms
for KNN the accuracy is 42% ( 51 individual,703 training image,290 test image, 14 image for each individual) and the time is 228371

2. not all images in test set is acceptable an error is appearing for a lot of images as attached image and i don't know why?

can any one help me fix these problems? I will show you code if you want.

Thanx