Revert "’視差を三重に計算していたので修正。 #53"

This reverts commit 37acb4a39cdc3ec49034e2a4dfc163ea6b310442.
Revert "Merge branch 'id/53' #53"

This reverts commit dc9ca05c7aff34b3730ba11848ada3b7efe80434, reversing
changes made to 6269e190d4eb38381cbd37a385780325555140ac.