Coverage for hml/sumImageWithinCircle.py: 4%

1#!/usr/bin/env python3 

2 

3# Define function ... 

4def sumImageWithinCircle(img, xmin, xmax, ymin, ymax, r, /, *, cx = 0.0, cy = 0.0, ndiv = 16): 

5 """ 

6 Sum the pixel values on an image that are within a hard circular mask. 

7 

8 Arguments: 

9 img -- 2D image with axes (ny, nx) 

10 xmin -- left edge of leftmost pixel 

11 xmax -- right edge of rightmost pixel 

12 ymin -- lower edge of lowermost pixel 

13 ymax -- upper edge of uppermost pixel 

14 r -- radius of circle 

15 

16 Keyword arguments: 

17 cx -- x position of centre of circle (default 0.0) 

18 cy -- y position of centre of circle (default 0.0) 

19 ndiv -- number sub-divisions (default 16) 

20 

21 Note: 

22 This function is crying out for FORTRAN+OpenMP. 

23 """ 

24 

25 # Import special modules ... 

26 try: 

27 import numpy 

28 except: 

29 raise Exception("\"numpy\" is not installed; run \"pip install --user numpy\"") from None 

30 

31 # Import sub-functions ... 

32 from .findFractionOfPixelWithinCircle import findFractionOfPixelWithinCircle 

33 

34 # Create nodes relative to the centre of the circle ... 

35 xaxis = numpy.linspace(xmin, xmax, num = img.shape[1] + 1) - cx 

36 yaxis = numpy.linspace(ymin, ymax, num = img.shape[0] + 1) - cy 

37 

38 # Find out the distance of each node to the centre of the circle ... 

39 dist = numpy.zeros((yaxis.size, xaxis.size), dtype = numpy.float64) 

40 for ix in range(xaxis.size): 

41 for iy in range(yaxis.size): 

42 dist[iy, ix] = numpy.hypot(xaxis[ix], yaxis[iy]) 

43 

44 # Initialize total ... 

45 tot = 0.0 

46 

47 # Loop over x-axis ... 

48 for ix in range(img.shape[1]): 

49 # Loop over y-axis ... 

50 for iy in range(img.shape[0]): 

51 # Skip this pixel if it is empty ... 

52 if img[iy, ix] == 0.0: 

53 continue 

54 

55 # Skip this pixel if it is all outside of the circle ... 

56 if numpy.all(dist[iy:iy + 2, ix:ix + 2] >= r): 

57 continue 

58 

59 # Check if this pixel is entirely within the circle or if it 

60 # straddles the circumference ... 

61 if numpy.all(dist[iy:iy + 2, ix:ix + 2] <= r): 

62 # Add all of the value to total ... 

63 tot += img[iy, ix] 

64 else: 

65 # Add part of the value to total ... 

66 tot += img[iy, ix] * findFractionOfPixelWithinCircle( 

67 xaxis[ix], 

68 xaxis[ix + 1], 

69 yaxis[iy], 

70 yaxis[iy + 1], 

71 r, 

72 cx = 0.0, 

73 cy = 0.0, 

74 ndiv = ndiv, 

75 ) 

76 

77 # Return answer ... 

78 return tot