python-2.7 | SimpleCV - TypeError: 'float' object cannot be interpreted as an index

Question

I'm trying to build a Image dewarping tool using simpleCV and python2.7.

The code below worked perfectly fine before(when I was on Ubuntu 16.04.1 LTS) but I recently updated to the Ubuntu 17.04 and I get this error now.

Here is the function:

def buildMap(Ws, Hs, Wd, Hd, R1, R2, Cx, Cy):
    map_x = np.zeros((Hd, Wd),np.float32)
    map_y = np.zeros((Hd, Wd),np.float32)
    rMap = np.linspace(R1, R1 + (R2 - R1), Hd)
    thetaMap = np.linspace(0, 0 + float(Wd) * 2.0 * np.pi, Wd)
    sinMap = np.sin(thetaMap)
    cosMap = np.cos(thetaMap)

    for y in xrange(0, int(Hd-1)):
        map_x[y] = Cx + rMap[y] * sinMap
        map_y[y] = Cy + rMap[y] * cosMap

    return map_x, map_y

and this is the error I get:

Exception in thread Thread-1:
Traceback (most recent call last):
  File "/usr/lib/python2.7/threading.py", line 801, in __bootstrap_inner
    self.run()
  File "/usr/lib/python2.7/threading.py", line 754, in run
    self.__target(*self.__args, **self.__kwargs)
  File "./fy360.py", line 189, in new_dewarp
    xmap, ymap = buildMap(Ws, Hs, Wd, Hd, R1, R2, Cx, Cy)
  File "./fy360.py", line 122, in buildMap
    map_x = np.zeros((Hd, Wd),np.float32)
TypeError: 'float' object cannot be interpreted as an index

what is the problem in my code?

because you cant pass index[5.4] and get value you need integer index[1or2] like this — Exprator, May 12 '17 at 05:50
Either `Hd` or `Wd` passed to this function is a float and not an integer. — Daniel F, May 12 '17 at 05:59
@DanielF , @Exparator `Hd` and `Wd ` values are `image frame sizes` so approximating them to an integer would compromise accuracy don't you think? — Sapnesh Naik, May 12 '17 at 06:06
Image frame sizes in pixels? Those are always integers. What would an image that's 16.5 pixels wide look like? — Nils Werner, May 12 '17 at 06:47

score 1 · Accepted Answer · answered May 12 '17 at 06:58

1

the np.zeros function needs Hd and Wd to be integers, not floats. Previous versions of Python would silently cast to integer, but newer versions give an error instead. Try adding this:

Hd = int(Hd)
Wd = int(Wd)

answered May 12 '17 at 06:58

Marijn van Vliet

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oh dang, I was under the impression that using float value was more accurate and resulted in better results. – Sapnesh Naik May 12 '17 at 07:00

python-2.7 | SimpleCV - TypeError: 'float' object cannot be interpreted as an index

1 Answers1