Unveiling the mystery - an ancient water clock with laser scanning

作者：Reka Vasszi

发明som设备跟踪时间ething mankind experimented with for thousands of years before the first digital clocks were invented. Ancient civilisations observed astronomical objects, such as the sun or the moon to determine time, dates and seasons. Along with sundials, water clocks were among the first devices used for measuring time from the 16^th世纪以来。

A more complex hydraulic-clock house, as compared to ancient water-clocks, was built attached to the Medersa Bouanania, school of theological sciences and congregational mosque in Fez, Morocco. The educational and religious complex was constructed in 1357 under the Merinid reign of Sultan Bou Inan who commissioned the hydraulic-clock to communicate the correct times of prayer to the muezzin, who leads and recites the call to prayer five times a day for worship in the mosque.

最近，Medersa由Fez市（Ader-Fès）开发和康复机构进行了一个修复项目。Ader-Fès与当地的工匠一起重建了Medersa独特的玻璃陶器马赛克及其神话般的雕刻雪松木天花板。

Aided with 3D laser scanning technology, specialists are now restoring the mysterious weight-powered hydraulic clock, which stopped working after it went into disuse when the Saadian dynasty replaced Merinid rulers and moved the capital from Fez to Marrakech. To reveal the mystery of the water clock’s internal mechanism and completely restore it, experts from Geo Lambert, a surveying company in Fez, scanned the façade and interior of the hydraulic-clock house with theLeica BLK360imaging laser scanner and theLeica RTC3603D现亚博ag真人规律实捕获解决方案。

Surveying in narrow areas

据说，一位魔术师创造了这个精心设计的液压时钟，从12个小门释放了金属球，到下梁上的黄铜碗，以打出五个祈祷的电话。不幸的是，这种独特的技术杰作并未在其原始状态下幸存下来。

为了使时钟再次栩栩如生，要求Geo Lambert测量师扫描时钟，产生矫形图像和3D网格模型，重点是2D高程和横截面。到达时钟对于专家来说是具有挑战性的，因为它垂直位于Mersa的墙壁上。此外，立面具有狭窄的拱门，较大的激光扫描设备无法合适。

“The BLK360 made it possible for me to survey a very narrow hall behind the clock thanks to its small size and quick setupGeo Lambert的高级测量师Adam Bouramdane说。

为了遇到挑战，Geo Lambert选择了便携式和轻量级的BLK360来详细捕捉时钟。作为马格里布（Maghreb）的第一家公司从摩洛哥（Leica）的新销售部门收购了BLK360，并且在3D扫描中具有较大的背景，调查专家能够在一天内扫描独特的时间保持设备及其环境。为了通过准确可靠的3D表示来管理项目复杂性，该团队用RTC360扫描了遗产建筑。

Scanning the finest details

After cleaning and registering the captured data, the team created a 3D model of the historic clock that will be the basis of future research and restoration.

“非常轻巧且便携式的良好点准确性和密度使BLK360和RTC360非常适合遗产测量，尤其是在狭窄的地区,” said Raghib Mehdi, associate surveyor at Geo Lambert.

Thanks to its small size, ease-of-use and accuracy, Leica Geosystems’ laser scanning technology opens new horizons in heritage preservation, as in the case of the mysterious clock in Morocco.