Winston,

Quad quality 5MPix  JP4 image should be 1.8-2MB size, yours is <500KB. For 
image processing I recommend using compression quality 97-98% as we do.

The sensor uses Bayer mosaic, so sensor output has 5 MPix, not 3*5MPix - the 
color appears during de-mosaic process. JP4 saves pixels as they come out from 
the sensor (raw), color interpolation should be done during processing. Here 
are images that illustrate JP4:

https://community.elphel.com/jp4/jp4demo.php

For your application I do not recommend converting to color. When using a 
simple viewer there will be not much advantage over the camera JPEG output. For 
image matching you may first use just green channel (green pixels are in a 
checkerboard pattern), add color separately. When we process such images we 
apply different lens correction for each color and only mix them after 
aberration correction. Using just green is the simplest way to process. 

Andrey




---- On Tue, 06 Mar 2018 21:12:18 -0800 Winston 
Zhang<winston.zh...@blacksesame.com.cn> wrote ---- 

    Hi, Andrey
       Please take a look at attachments. The rawJP4 image was captured from 
the camera, and I converted it and got the result as result.png. But when I 
magnified this image, I found some block included 16x16 grid. I did not know 
the reason. Can you explain it.(The grid image please take look at grid.png).
       Another question is that the result image is single channel but not 
three channel like as rgb-channel. But if I converted it through the jp4viewer, 
the result is color image. Why? How do you do this?
     
 
   
 Best Regrad!
 Yicheng-Zhang
 Email:  winston.zh...@blacksesame.com.cn
 Teil:    18516291005
 Addr:   707 room, 7th floor, building 4th, No.1761, Zhangdong road, Pudong area
 
  
   发件人: Andrey Filippov [mailto:and...@elphel.com] 
 发送时间: 2018年3月6日 星期二 15:58
 收件人: Winston Zhang <winston.zh...@blacksesame.com.cn>
 抄送: Elphel Support <support-list@support.elphel.com>; Elphel Sales | 
Olga Filippova <sa...@elphel.com>; Tao Zhang 
<tao.zh...@blacksesame.com.cn>; Qun Gu <qun...@blacksesame.com>; 
Pioneer Li <pioneer...@blacksesame.com.cn>
 主题: Re: [Elphel-support] 答复: 答复: 答复: sync stereo with lidar
 
 
  
  Winston,
 
 There are several ways how to set the JP4 mode:
 
 1) set it from the camera GUI (click Camera Control Interface port #), then 
click camera icon (top left), then "More details" and select color mode to jp4.
 2) set with "Parameter Editor": follow Parameter Editor from the home page, 
check bit 2 - "Image color, quality ..." -> "View/Edit Current", set "COLOR: 
line New value to 5 (it is jp4) and click "Apply" button.
 3) make this mode default(after either 1) or 2) )- save current settings in 
"Parameter Editor" (previous page) - Press topmost "Save" button (you may later 
change comments for the settings). Then you may set saved settings as default 
(select it and then press "Update default"). Next time you start the camera it 
will use these settings.
 Then repeat the same for the other channel.
 
 Andrey
   
 ---- On Mon, 05 Mar 2018 01:46:22 -0800 Winston 
Zhang<winston.zh...@blacksesame.com.cn> wrote ---- 
 
    Hello, Andrey,
              I need information inside camera. How can I get jp4 format image? 
What is the image default format? If I try the command line “wget 
http://192.168.0.9:2323/img -O filename.jp4”, Can I get the jp4 format Image?   
          Thank you! 
 ”
  
     
 
    
  Best Regrad!
  Yicheng-Zhang
  Email:  winston.zh...@blacksesame.com.cn
  Teil:    18516291005
  Addr:   707 room, 7th floor, building 4th, No.1761, Zhangdong road, Pudong 
area
 
  
   发件人: Andrey Filippov [mailto:and...@elphel.com] 
 发送时间: 2018年3月2日 星期五 10:47
 收件人: Winston Zhang <winston.zh...@blacksesame.com.cn>; Elphel Support 
<support-list@support.elphel.com>
 抄送: Tao Zhang <tao.zh...@blacksesame.com.cn>; Elphel Support 
<support-list@support.elphel.com>; Elphel Sales | Olga Filippova 
<sa...@elphel.com>; Qun Gu <qun...@blacksesame.com>; Pioneer Li 
<pioneer...@blacksesame.com.cn>
 主题: Re: 答复: 答复: [Elphel-support] sync stereo with lidar
 
 
  
  Hello Winston,
 
 Do you need information inside camera or for post-processing on a host PC?
 
 Sensor has 12 bits, and using JP4 format (https://wiki.elphel.com/wiki/JP4) 
you can restore image data with the error less than the pixel shot noise
 
 Here is an article explaining why it is so:
    
 
  http://linuxdevices.io/how-many-bits-are-really-needed-in-the-image-pixels/
 
   
 
  With ImageJ plugin you can convert JP4 file to 32-bit TIFF
 
   
 
  Andrey
 
   
 
   
 
   
 
   
 
   
 
   
 
   
 
  ---- On Thu, 01 Mar 2018 17:17:14 -0800 Winston 
Zhang<winston.zh...@blacksesame.com.cn> wrote ---- 
 
    Hello,
       Does this camera image pixel have 10 bit of the single channel? And how 
can I get it? Thank you.
  
     
 
    
  Best Regrad!
  Yicheng-Zhang
  Email:  winston.zh...@blacksesame.com.cn
  Teil:    18516291005
  Addr:   707 room, 7th floor, building 4th, No.1761, Zhangdong road, Pudong 
area
 
  
   发件人: Andrey Filippov [mailto:and...@elphel.com] 
 发送时间: 2018年2月1日 星期四 13:49
 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: 答复: [Elphel-support] sync stereo with lidar
 
 
  
  Tao,
 
 USB GPS does not have 1pps signal (only serial has), precise synchronization 
is not possible that way. GPS time is available in each frame Exif header data 
- recorded on internal SSD or sent over the network.
 
 The high resolution time stamps (1 microsecond step) are also provided with 
each  image, but they use internal camera clock, not the GPS.
 
 This is why for precise synchronization you need to use event logger- it 
records events and timestamps them using the same clock.
 
 If you had serial GPS with  https://wiki.elphel.com/wiki/103696 - you would 
still need to use event logger - with serial GPS there will be 1 PPS precise 
GPS events timestamped with camera internal clock, and the images timestamped 
wit the same clock - that provides absolute calibration for the camera internal 
clock.
 
 Without serial GPS you may use pulses from the LIDAR (it is possible to 
provide LIDAR pulse number over the Ethernet in addition to the precise time 
over the sync cable)
 
 Andrey
   
 ---- On Wed, 31 Jan 2018 18:12:00 -0800 Tao 
Zhang<tao.zh...@blacksesame.com.cn> wrote ---- 
 
    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> 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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