Functionalized programs

ComputerVision/Week_10_11/Page_4_Reading_Videos.py

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+import cv2
+
+def ReadVideo(videoPath):
+    cap = cv2.VideoCapture(videoPath)
+    #Read	video	frames	until	available	
+    while(cap.isOpened()):
+        ret, frame = cap.read()
+        if ret== True:
+            #Quickly	display	image		
+            cv2.imshow('frame',frame)
+            if cv2.waitKey(1) & 0xFF == ord('q'):
+                break
+        else:
+            break
+    # Release everything if job is finished
+    cap.release()
+    cv2.destroyAllWindows()
+
+#https://docs.opencv.org/3.0-beta/doc/py_tutorials/py_gui/py_video_display/py_video_display.html

ComputerVision/Week_10_11/Page_5_Writing_Videos.py

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+import cv2
+def WriteVideo(videoPath):
+    cap = cv2.VideoCapture(videoPath)
+    # Define the codec and create VideoWriter object
+    fourcc = cv2.VideoWriter_fourcc(*'XVID')
+    out = cv2.VideoWriter('output.avi',fourcc, 47.95, (1280,720))
+
+    while(cap.isOpened()):
+        ret, frame = cap.read()
+        if ret==True:
+            frame = (255-frame) #Invert
+            # write the inversed frame
+            out.write(frame)       
+            #Quickly	display image	using the	image command	
+            cv2.imshow('frame',frame)
+            if cv2.waitKey(1) & 0xFF == ord('q'):
+                break
+        else:
+            break
+    # Release everything if job is finished
+    cap.release()
+    out.release()
+    cv2.destroyAllWindows()
+
+    return out #(out,'output.avi') #could return both the output video and path
+
+'''import Page_4_Reading_Videos as readV #small test program
+WriteVideo("vtest.avi")
+readV.ReadVideo("output.avi")'''
+
+#https://docs.opencv.org/3.0-beta/doc/py_tutorials/py_gui/py_video_display/py_video_display.html
+#It seems opencv is the main librray for video streaming, could not find for direct playing like implay on matlab

ComputerVision/Week_2/Page_34_LUT.py

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+#*************
+# Not Tested
+#*************
+import numpy as np 
+
+def CalculateSimpleLUT(a):
+    x = [i for i in range(256)]
+    LUT = [ 255/(1+np.exp(-a*(j-127)/32)) for j in x]
+    return LUT
+
+#OR
+def CalculateSimpleLUT_2(a):
+    LUT = [ 255/(1+np.exp(-a*(x-127)/32)) for x in range(256)]
+    return LUT

ComputerVision/Week_2/Page_45_Multi-Band_Histogram_Calculator_1.py

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+#*************
+# Not Tested
+#*************
+import numpy as np
+
+def histogram(I): #multiband histogram calculation
+
+    h,w,d=I.shape
+
+    hist=np.zeros([256,d],dtype=np.uint8) #allocate the histogram
+
+    #range through the intensity values
+    for g in range(256):
+        hist[g][0] = sum([i.tolist().count(g) for i in I[:,:,0]]) #accumulate
+        hist[g][1] = sum([i.tolist().count(g) for i in I[:,:,1]])
+        hist[g][2] = sum([i.tolist().count(g) for i in I[:,:,2]])
+
+    return hist
+

ComputerVision/Week_2/Page_71_Histogram_Matching_Algorithm.py

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+import cv2
+import numpy as np
+
+
+def HistogramMatch(I,J):
+    '''I=cv2.imread("tony-stark.jpg",0)
+    J=cv2.imread("thanos.jpg",0)'''
+
+    '''cv2.imshow("Original Image",I)
+    cv2.imshow("Target Image",J)'''
+
+    Hi,Wi = I.shape
+    Hj,Wj = J.shape
+
+    K=np.zeros([Hi,Wi],dtype=np.uint8) 
+
+    mj=np.min(J)
+    Mj=np.max(J)
+
+    mi=np.min(I)
+    Mi=np.max(I)
+
+    PI_noncumulative,edges=np.histogram([a for a in I.ravel()],256,[0,256],[0,1])
+    PI=PI_noncumulative.cumsum()
+    PJ_noncumulative,edges=np.histogram([a for a in J.ravel()],256,[0,256],[0,1])
+    PJ=PJ_noncumulative.cumsum()
+
+    gj=mj
+    for gi in range(mi,Mi):
+        while gj<256 and PI[gi]<1 and PJ[gj]<PI[gi]:
+            gj = gj + 1
+        K[I==gi]=gj
+
+    '''cv2.imshow("Remapped Image",K)   
+    cv2.waitKey(0)
+    cv2.destroyAllWindows()  '''     
+    return K
+
+'''I=cv2.imread("tony-stark.jpg",0) #example program
+J=cv2.imread("thanos.jpg",0)
+cv2.imshow("Remapped Image", HistogramMatch(I,J))   
+cv2.waitKey(0)
+cv2.destroyAllWindows()  '''

ComputerVision/Week_2/Page_76_Define_K.py

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+import cv2
+import numpy as np
+
+
+def ApplyLUTWithGamma(I,gamma):
+
+    invGamma =gamma
+    lut = np.array([((i / 255.0) ** invGamma) * 255 for i in np.arange(0, 256)]).astype("uint8")
+
+    K= cv2.LUT(I, lut) #LUT mapping function of Python
+
+    '''cv2.imshow("Original",I)  #image showing
+    cv2.imshow("K",K)
+    cv2.waitKey(0)
+    cv2.destroyAllWindows()'''
+    return K
+
+'''I=cv2.imread("thanos.jpg",0) #example program
+cv2.imshow("K",ApplyLUTWithGamma(I,0.8))
+cv2.waitKey(0)
+cv2.destroyAllWindows()'''
+
+    # Sources:
+    # www.learnopencv.com/applycolormap-for-pseudocoloring-in-opencv-c-python/
+    # www.programcreek.com/python/example/89460/cv2.LUT
+
+#ApplyLUTWithGamma("tony-stark.jpg",0.3)  original run

ComputerVision/Week_2/Page_78_Look_Up_Table_For_Histogram_Matching.py

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+#*************
+# Not Tested
+#*************
+import numpy as np
+
+def CalculateLUT(I,J):    
+
+    PI_noncumulative,edges=np.histogram([a for a in I.ravel()],256,[0,256],[0,1])
+    PI=PI_noncumulative.cumsum()
+    PJ_noncumulative,edges=np.histogram([a for a in J.ravel()],256,[0,256],[0,1])
+    PJ=PJ_noncumulative.cumsum()
+
+    LUT = np.zeros([256])
+    gJ=0
+
+    for gI in range(256):
+        while PJ[gJ] < PI[gI] and gJ<256:
+            gJ = gJ+1
+        LUT[gI] = gJ
+
+    return LUT

ComputerVision/Week_3/Page_17_Example.py

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+import cv2
+
+import numpy as np
+import math
+
+def cropBorders(img,tol=0): #https://codereview.stackexchange.com/questions/132914/crop-black-border-of-image-using-numpy  answer by Divakar
+    mask=img>0
+    return img[np.ix_(mask.any(1),mask.any(0))]
+
+def PlateBW(I):
+
+    '''I=cv2.imread("LicensePlate.png",0) #read image
+    cv2.imshow("License Plate Original", I)'''
+
+    height,width=I.shape[:2]
+
+    M= cv2.getRotationMatrix2D((width/2,height/2),-15,1)
+
+    sin = math.sin(M[0,0])
+    cos = math.cos(M[0,1])
+    bound_w = int((height * abs(sin)) + (width * abs(cos)))
+    bound_h = int((height * abs(cos)) + (width * abs(sin)))
+
+    M[0, 2] += ((bound_w / 2) - width/2)
+    M[1, 2] += ((bound_h / 2) - height/2)
+
+    J1 = cv2.warpAffine(I,M,(bound_w,bound_h))
+
+    J1=cropBorders(J1)
+    '''cv2.imshow("License Plate Rotated", J1)'''
+
+
+    tform=np.float32([ [1,0.3,0],[0,1,0]])
+
+
+    h,w=J1.shape[:2]  #height and width values of the image
+    J2=np.zeros([h*2,w*2],dtype=np.uint8)
+
+    J2 = cv2.warpAffine(J1,tform,(w*2,h*2))    
+    J2=cropBorders(J2)
+
+    '''cv2.imshow("License Plate Skewed", J2)    
+    cv2.waitKey(0)
+    cv2.destroyAllWindows()'''
+    return J2
+
+
+#**************-color version
+def PlateColor(I):
+    '''I=cv2.imread("LicensePlate.png") #read image
+    cv2.imshow("License Plate Original", I)'''
+
+    height,width=I.shape[:2]
+
+    # Rotate clockwise 15 degrees to align base
+    M= cv2.getRotationMatrix2D((width/2,height/2),-15,1)
+    J1 = cv2.warpAffine(I,M,(width,height))
+    '''cv2.imshow("License Plate Rotated", J1)'''
+
+
+    # Now apply a skew
+    tform=np.float32([ [1,0.3,0],[0,1,0]])
+    height,width=J1.shape[:2]  
+    J2=np.zeros([height,width],dtype=np.uint8)
+    J2 = cv2.warpAffine(J1,tform,(width,height))
+    '''cv2.imshow("License Plate Skewed", J2)   
+    cv2.waitKey(0)
+    cv2.destroyAllWindows()'''
+    return J2
+
+
+'''I=cv2.imread("LicensePlate.png") #read image   #small test program
+IBW=cv2.imread("LicensePlate.png",0) #read image
+
+cv2.imshow("BW", PlateBW(IBW))   
+cv2.imshow("Color", PlateColor(I))   
+cv2.waitKey(0)
+cv2.destroyAllWindows()'''
+
+

ComputerVision/Week_8/Page_10_Read_Image.py

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+import cv2
+
+
+def ReadGrayImage(imagePath):
+    return cv2.imread(imagePath,0)
+
+'''cv2.imshow("Birds",ReadGrayImage("birds.png"))  #example program
+cv2.waitKey(0)
+cv2.destroyAllWindows()'''

ComputerVision/Week_8/Page_10_Something.py

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+import cv2
+import numpy as np
+
+
+def ThresholdWithFunction(I,T):
+    ret,B=cv2.threshold(I, T, 255, cv2.THRESH_BINARY_INV)
+    return B
+
+def ThresholdWithBoolean(I,T):
+    B = np.zeros((I.shape))   
+    B[I<30] = 255
+    return B
+
+'''I = cv2.imread("birds.png",0)  #example program
+T=30
+cv2.imshow("Thresholded	at	30 Function",ThresholdWithFunction(I,T))
+cv2.imshow("Thresholded	at	30 Boolean",ThresholdWithBoolean(I,T))
+
+cv2.waitKey(0)
+cv2.destroyAllWindows()'''

ComputerVision/Week_8/Page_11_Basic_Thresholding_Algorithm.py

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+#*************
+# Not Tested
+#*************
+import numpy as np
+
+def BasicThreshold(I,T):
+    Y=0
+    X=0
+    T=0
+    B =np.zeros(I.shape,dtype=np.bool)
+
+    for y in range(0,Y):
+        for x in range(0,X):
+            B[y][x]= (I[y][x]>=T)        

ComputerVision/Week_8/Page_11_Bird_Counting.py

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+import cv2
+import numpy as np
+
+def Label(I):
+    ret,B=cv2.threshold(I, 70, 255, cv2.THRESH_BINARY_INV)
+    '''cv2.imshow("Thresholded	at	70",B)'''
+    J = cv2.morphologyEx(B, cv2.MORPH_OPEN, np.ones((3,3),np.uint8))
+    '''cv2.imshow('Opened',J)'''
+
+    labelCount, labels = cv2.connectedComponents(J)
+    # Map component labels to hue val
+    label_hue = np.uint8(179*labels/np.max(labels))
+    blank_ch = 255*np.ones_like(label_hue)
+    labeled_img = cv2.merge([label_hue, blank_ch, blank_ch])
+
+    # cvt to BGR for display
+    L = cv2.cvtColor(labeled_img, cv2.COLOR_HSV2BGR)
+
+    # set bachground label to black
+    L[label_hue==0] = 0
+
+    '''cv2.imshow('Labeled. Number of birds = ' + str(labelCount-1), L) #backgorund is also labeled    
+    cv2.waitKey(0)
+    cv2.destroyAllWindows()'''
+    return (L,labelCount-1)
+
+    #source: https://stackoverflow.com/questions/46441893/connected-component-labeling-in-python
+
+'''I = cv2.imread("birds.png",0)   #example program
+(img,count)=Label(I)
+cv2.imshow('Labeled. Number of birds = ' + str(count), img) 
+cv2.waitKey(0)
+cv2.destroyAllWindows()'''

ComputerVision/Week_8/Page_12_Finding_a_Good_Threshold.py

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+import cv2
+from matplotlib import pyplot as plt
+
+def Threshold(I,T):
+    '''cv2.imshow("Lungs",I)'''
+
+    plt.hist(I.ravel(),bins=255)
+    plt.title("Histogram h(I)")
+    '''plt.show()'''
+
+    ret,B=cv2.threshold(I, T, 255, cv2.THRESH_BINARY)
+    '''cv2.imshow("Thresholded	at "+str(T),B)   
+    cv2.waitKey(0)
+    cv2.destroyAllWindows()'''
+    return (B,plt)
+
+
+
+'''I = cv2.imread("lung.png",0)  #example program
+T = 130
+cv2.imshow("Thresholded	at " + str(T),Threshold(I,T)[0])
+Threshold(I,T)[1].show()
+cv2.waitKey(0)
+cv2.destroyAllWindows()'''