Hi Andrey,
We prefer to use GPS to synchronize stereo with lidar.
Where do those images that contain timestamp store in internal disk? Can we get 
it from ethernet continuously?

Tao Zhang
章   涛

发件人: Andrey Filippov [mailto:and...@elphel.com]
发送时间: 2018年2月1日 1:52
收件人: Tao Zhang <tao.zh...@blacksesame.com.cn>
抄送: Elphel Support <support-list@support.elphel.com>; Elphel Sales | Olga 
Filippova <sa...@elphel.com>; Winston Zhang <winston.zh...@blacksesame.com.cn>; 
Qun Gu <qun...@blacksesame.com>; Pioneer Li <pioneer...@blacksesame.com.cn>
主题: Re: [Elphel-support] sync stereo with lidar

Hi Tao,

There are several ways how to do that:
One method would be be to get camera sync pulses for each frame and use 
external electronics to match with the LIDAR.
Another is to provide pulses from the LIDAR to the camera and record them with 
in-camera FPGA logger (https://wiki.elphel.com/wiki/Event_logger), together 
with the camera frames. In this case the camera will record 2 types of events:
 -  image frames with the frame number, frame timestamp that will be recorded 
in each frame header as Exif.
 - external pulse
Each of the two types of events will have a logger timestamp (with microsecond 
resolution). Logger can also record GPS timestamps (for serial GPS only and 
103696 board -https://wiki.elphel.com/wiki/103696) and IMU 
(https://wiki.elphel.com/wiki/103695), in your case there are just 2 types 
listed above.

Both output (+5V pulses) and input (3.3V..5.0V) are available through the 2.5mm 
audio connector (marked "sync" 
https://wiki.elphel.com/images/0/0f/NC393-CS_marked_ports.jpeg ), here is the 
pinout and description: https://wiki.elphel.com/wiki/103891 .

Andrey

---- On Wed, 31 Jan 2018 04:19:04 -0800 Tao 
Zhang<tao.zh...@blacksesame.com.cn<mailto:tao.zh...@blacksesame.com.cn>> wrote 
----
Hi Andrey,
We are going to use stereo with lidar. We need to sync stereo frames with lidar 
point cloud. Do you have any suggestions on how to do that?
Thanks.

Tao Zhang
章   涛

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