code: def replace_zeros(self, val, zero_thresh=0.0):
          
          new_data = self.data.copy()
          new_data[new_data <= zero_thresh] = val
          return type(self)(new_data.astype(self.data.dtype), frame=self._frame)
docs: Replaces all zeros in the image with a specified value
  
          Returns
          -------
          image dtype
               value to replace zeros with