Numpy image – rotate matrix 270 degrees

Question:

I’ve got a Numpy 2d array that represents a grey-scale image and I need to rotate it 270 degrees. Might be being a bit thick here but the two ways I can find to do this seem quite… circulous:

rotated = numpy.rot90(numpy.rot90(numpy.rot90(orignumpyarray)))

rotated = numpy.fliplr(numpy.flipud(numpy.rot90(orignumpyarray)))

I’m thinking there must be a better way to do this in one operation. Basically a rot270() function? Any ideas?

Asked By: Mikesname

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Answers:

You can tell rot90 to rotate several times, this should work:

rotated = numpy.rot90(orignumpyarray,3)
Answered By: Anders Lindahl
rotated_array =numpy.rot90(orignumpyarray,3)

Explanation of the function:

numpy.rot90(a,b)
a = Array which you want to rotate
b = How many times you want to rotate it by 90 degrees. For here you want 270° so
90° * 3 = 270° that is why b = 3 here.

Answered By: Krunal Degamdiya