diff --git a/Homework2/Problem2_3/200_redCell.png b/Homework2/Problem2_3/200_redCell.png
new file mode 100644
index 0000000..5f2028d
Binary files /dev/null and b/Homework2/Problem2_3/200_redCell.png differ
diff --git a/Homework2/Problem2_3/BRIEF descriptor.py b/Homework2/Problem2_3/BRIEF descriptor.py
new file mode 100644
index 0000000..664e384
--- /dev/null
+++ b/Homework2/Problem2_3/BRIEF descriptor.py	
@@ -0,0 +1,54 @@
+
+# coding: utf-8
+
+# In[17]:
+
+import numpy as np
+import math
+from PIL import Image, ImageDraw
+import random
+
+
+givenImg = Image.open('C:\Users\Char\Downloads\\200_redCell.png', 'r').convert('LA')
+#givenImg.show()
+(width, height) = givenImg.size
+imgData = list(givenImg.getdata())
+
+numOfPairs = 20;
+samplingPairs = makeSamplingPair(numOfPairs, width, height)
+print samplingPairs
+
+BRIEFDescriptor = makeBRIEFDescriptor(samplingPairs, numOfPairs, imgData, width, height)
+print BRIEFDescriptor
+
+
+# In[15]:
+
+def makeSamplingPair(numOfPairs, width, height):
+    samplingPairs = list();
+    
+    for i in range(numOfPairs):
+        X1 = int(width*random.random());
+        Y1 = int(height*random.random());
+        X2 = int(width*random.random());
+        Y2 = int(height*random.random());
+        currSamplingPair =[[X1, Y1], [X2, Y2]]
+        samplingPairs.append(currSamplingPair);
+        
+    return samplingPairs;
+
+
+# In[11]:
+
+def makeBRIEFDescriptor(samplingPairs, numOfPairs, imgData, width, height):
+    BRIEFDescriptor = list();
+    for currPair in samplingPairs:
+        valueInPt1 = imgData[currPair[0][0]+width*currPair[0][1]][0];
+        valueInPt2 = imgData[currPair[1][0]+width*currPair[1][1]][0];
+        if(valueInPt1 > valueInPt2):
+            BRIEFDescriptor.append(1);
+        else:
+            BRIEFDescriptor.append(0);
+    
+    return BRIEFDescriptor;
+
diff --git a/Homework2/Problem2_3/FAST edge detector.py b/Homework2/Problem2_3/FAST edge detector.py
new file mode 100644
index 0000000..0325e85
--- /dev/null
+++ b/Homework2/Problem2_3/FAST edge detector.py	
@@ -0,0 +1,100 @@
+
+# coding: utf-8
+
+# In[9]:
+
+import numpy as np
+from PIL import Image, ImageDraw
+
+
+givenImg = Image.open('C:\Users\Char\Downloads\\200_redCell.png', 'r').convert('LA')
+givenImg.show()
+
+
+
+
+(width, height) = givenImg.size
+pixels = list(givenImg.getdata())
+threshold = 10
+cornerList = FAST9CornerDetector(pixels, width, height, threshold)
+
+draw = ImageDraw.Draw(givenImg)
+
+for currCorner in cornerList:
+    draw.ellipse((currCorner[0]-1, currCorner[1]-1, currCorner[0]+1, currCorner[1]+1),
+                 fill=0)
+
+givenImg.show()
+
+
+# In[2]:
+
+def FAST9CornerDetector(pixelList, width, height, threshold):
+    cornerCoordList = list();
+    for currX in range(width):
+        for currY in range(height):
+            isCorner = judgeCornerPoint(currX, currY, pixelList, width, height, threshold);
+            if(isCorner == True):
+                cornerCoordList.append([currX, currY]);
+    
+    return cornerCoordList;
+            
+
+
+# In[3]:
+
+def judgeCornerPoint(currX, currY, pixelList, width, height, threshold):
+    SurrondingPoints = [[currX, currY+3], [currX+1, currY+3], [currX+2, currY+2],
+                        [currX+3, currY+1], [currX+3, currY], [currX+3, currY-1], [currX+2, currY-2],
+                        [currX+1, currY-3], [currX, currY-3], [currX-1, currY-3], [currX-2, currY-2],
+                        [currX-3, currY-1], [currX-3, currY], [currX-3, currY+1], [currX-2, currY+2],
+                        [currX-1, currY+3]]
+    
+    brightOfCurrCoord = pixelList[currX+currY*width][0];
+    continuousState = 0;
+    
+    for surrCoord in SurrondingPoints:
+        if ((surrCoord[0] >= 0) & (surrCoord[1] >= 0) & (surrCoord[0] < width) & (surrCoord[1] < height)):
+                brightOfSurrCoord = pixelList[surrCoord[0]+surrCoord[1]*width][0];
+                if(continuousState >= 0):
+                    if(brightOfSurrCoord > brightOfCurrCoord+threshold):
+                        continuousState = continuousState+1;
+                    elif(brightOfSurrCoord < brightOfCurrCoord-threshold):
+                        continuousState = -1;
+                    else:
+                        continuousState = 0;   
+                else:
+                    if(brightOfSurrCoord > brightOfCurrCoord+threshold):
+                        continuousState=1;
+                    elif(brightOfSurrCoord < brightOfCurrCoord-threshold):
+                        continuousState = continuousState-1;
+                    else:
+                        continuousState = 0;
+                        
+        if((continuousState == 9)|(continuousState == -9)):
+            return True;
+        
+    if(continuousState > 0):
+        for i in range(9-continuousState):
+            surrCoord = SurrondingPoints[i]
+            if ((surrCoord[0] >= 0) & (surrCoord[1] >= 0) & (surrCoord[0] < width) & (surrCoord[1] < height)):
+                brightOfSurrCoord = pixelList[surrCoord[0]+surrCoord[1]*width][0];
+                if(brightOfSurrCoord > brightOfCurrCoord+threshold):
+                    continuousState = continuousState+1;
+        
+        if(continuousState == 9):
+            return True;
+    
+    if(continuousState < 0):
+        for i in range(9+continuousState):
+            surrCoord = SurrondingPoints[i]
+            if ((surrCoord[0] >= 0) & (surrCoord[1] >= 0) & (surrCoord[0] < width) & (surrCoord[1] < height)):
+                brightOfSurrCoord = pixelList[surrCoord[0]+surrCoord[1]*width][0];
+                if(brightOfSurrCoord > brightOfCurrCoord+threshold):
+                    continuousState = continuousState-1;
+        
+        if(continuousState == -9):
+            return True;
+    
+    return False;
+