title: Gamma correction in python
body: <p>Gamma correction is a simple and elegant algorithm to change the image brightness.<br />
  The formula is:<br />
  <img src="https://latex.codecogs.com/svg.image?I_%7Bout%7D=I%5E%7B%5Cgamma%7D" title="I_{out}=I^{\gamma}" /><br />
  But unfortunately this algorithm is not implemented in opencv.<br />
  So how is the simplest way to do it in python?</p>