Otsu's Binarization, typo at line 172 and line 176

[1993jayant]

At line 172: q_1(t) = \sum_{i=1}^{t} P(i) \quad & \quad q_2(t) = \sum_{i=t+1}^{I} P(i) instead of q_1(t) = \sum_{i=1}^{t} P(i) \quad & \quad q_1(t) = \sum_{i=t+1}^{I} P(i). In the formula while defining q1 and q2, instead of writing q2(t), it was written q1(t) for q2 definition.

At line 176: \quad \sigma_2^2(t) = \sum_{i=t+1}^{I} [i-\mu_2(t)]^2 \frac{P(i)}{q_2(t)}. Here, it was written [i-\mu_1(t)]^2 instead of [i-\mu_2(t)]^2.