Question about keypoint.octave

[Zhuifeng414]

Thanks for providing such a handsome sift code. But I really could not figure out why you calculate keypoint.octave like this

keypoint.octave = octave_index + image_index * (2 ** 8) \
               + int(round((extremum_update[2] + 0.5) * 255)) * (2 ** 16)

Thanks.

[rmislam]

Hi @Zhuifeng414, thanks for looking at my code! Is there something specific about this line you want clarification on?

[Lvwenchao]

I have the same question. Why should the octave and size of kps be calculated in this way

kps.octave = octave_index + s_index * (2 ** 8) + int(round((delta_xyz[2] + 0.5) * 255)) * (2 ** 16)
kps.size = self.sigma0 * (2 ** ((s_index + delta_xyz[2]) / self.intvl)) * (2 ** octave_index + 1)