Re: [Elphel-support] 答复: 答复: 答复: 答复: 答复: 答复: 答复: 答复: 答复: 答复: Re: Quote for 1 NC393-Stereo camera

[Elphel Support]

 On Mon, 08 Jan 2018 20:58:46 -0800 Winston 
Zhangwinston.zh...@blacksesame.com.cn wrote  

Hi Andrey
   I have set all the same parameters.  Please look at attachments. How did 
I set the 245 as your shown on screenshot? This page on mine did not show any 
object, please look at the attachments.
   And two camera images change asynchronously. How can I make this two 
camera image changes synchronously?
  








Winston, to set same parameter as "245" - just open and press "Apply"

http://192.168.0.9/parsedit.php?sensor_port=0AEXP_LEVEL=0xf500refresh


http://192.168.0.9/parsedit.php?sensor_port=1AEXP_LEVEL=0xf500refresh

Or
 On that user interface that you've sent last video press on "more details..." 
(it is just above the sliders) and then on the yellow tab (#4) - that will open 
AE contols like on Fig.4 here:
https://wiki.elphel.com/wiki/Autoexposure

Andrey



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Re: [Elphel-support] 答复: 答复: 答复: 答复: 答复: 答复: 答复: 答复: Re: Quote for 1 NC393-Stereo camera

[Elphel Support]

Hello Winston,

got the video - difficult to tell w/o settings. Can you open these URLs (modify 
IP if needed) and post the values?

for port 0:

http://192.168.0.9/parsedit.php?sensor_port=0EXPOSWOI_LEFTWOI_TOPWOI_WIDTHWOI_HEIGHTAUTOEXP_ONHISTWND_RWIDTHHISTWND_RHEIGHTHISTWND_RLEFTHISTWND_RTOPAUTOEXP_EXP_MAXAEXP_FRACPIXAEXP_LEVELAE_THRESHAE_PERIOD

for port 1:

http://192.168.0.9/parsedit.php?sensor_port=1EXPOSWOI_LEFTWOI_TOPWOI_WIDTHWOI_HEIGHTAUTOEXP_ONHISTWND_RWIDTHHISTWND_RHEIGHTHISTWND_RLEFTHISTWND_RTOPAUTOEXP_EXP_MAXAEXP_FRACPIXAEXP_LEVELAE_THRESHAE_PERIOD

Andrey




 On Mon, 08 Jan 2018 17:33:51 -0800 Winston 
Zhangwinston.zh...@blacksesame.com.cn wrote  

Hi Andrey, 
   Please receive the attachment.
  
 
 
   
 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: Elphel Support [mailto:support-list@support.elphel.com] 
 发送时间: 2018年1月9日 星期二 9:24
 收件人: Tao Zhang tao.zh...@blacksesame.com.cn
 抄送: Winston Zhang winston.zh...@blacksesame.com.cn; Elphel Sales | 
Olga Filippova sa...@elphel.com; Qun Gu qun...@blacksesame.com
 主题: Re: 答复: [Elphel-support] 答复: 答复: 答复: 答复: 答复: 答复: Re: Quote for 1 
NC393-Stereo camera
 
 
  
  Tao,
 
 OK, will wait for the picture. White balance does not need to change for the 
outdoor (maybe for night city with electrical lights - and I still recommend to 
use presets). You see there are conditions when it is easy to fool AWB, and 
while it may be OK for just a regular camera, you need to know exactly how the 
image is processed to match multiple images.
 
 The AWB algorithm is rather simple. It assumes that the brightest object in 
the scene is white - and in most cases it works. But when there is nothing 
white in the scene - AWB fails. 
 
 With AE you may try to change those values I mentioned earlier.
 
 Andrey
   
  On Mon, 08 Jan 2018 17:06:43 -0800 Tao 
Zhangtao.zh...@blacksesame.com.cn wrote  
 
Hi Andrey,
 We will fix the camera on a car. The light condition may change. AWB need to 
adapt to the change. For AE, the scene is normal in the office, there is not 
bright light. But it cannot converge to a stable status. We will attach images 
and videos of those problems later.
  
   Tao Zhang
  章   涛
 
  
   发件人: Elphel Support [mailto:support-list@support.elphel.com] 
 发送时间: 2018年1月9日 4:02
 收件人: Tao Zhang tao.zh...@blacksesame.com.cn; Elphel List 
support-list@support.elphel.com
 抄送: Winston Zhang winston.zh...@blacksesame.com.cn; Elphel Sales | 
Olga Filippova sa...@elphel.com; Qun Gu qun...@blacksesame.com
 主题: Re: [Elphel-support] 答复: 答复: 答复: 答复: 答复: 答复: Re: Quote for 1 NC393-Stereo 
camera
 
 
  
  Tao,
 
 I did not get the attached image to see your problem, but I expect you just 
need to modify the settings. Camera has a flexible control over AWB and AE to 
provide optimal operation for different lighting conditions. Most likely 
problem of of the instability is that there is a bright light source in the 
field of view.
 
 First you need to make AE stable, then set or disable AWB (it only needs to be 
changed when you move from the indoors to outdoors), so if you work outdoors 
you may just set AWB once and then save parameters - that will make image 
matching easier.
 
 For AE you may control:
 1) the AE window (camera will only consider exposure for the selected 
rectangle, ignoring lights outside it.
 2) The fraction of pixels that should have intensity values below certain 
threshold - reduce default value if there are lights in the FOV (especially 
electrical lights that have flicker)
 3) The level (default 250) - target of autoexposure.
 There are some illustrations on the wiki:  
https://wiki.elphel.com/wiki/Autoexposure
 
 Andrey
    On Mon, 08 Jan 2018 01:10:17 -0800 Tao 
Zhangtao.zh...@blacksesame.com.cn wrote  
 
BTW, your stereo AE has oscillation and AWB is not accurate. Do you have 
updated firmware to solve these problems?
  
   Tao Zhang
  章   涛
 
  
   发件人: Winston Zhang 
 发送时间: 2018年1月8日 16:54
 收件人: Oleg support-list@support.elphel.com
 抄送: Elphel Sales | Olga Filippova sa...@elphel.com; Dan Pan 
ad...@blacksesame.com; Tao Zhang tao.zh...@blacksesame.com.cn; 
Qun Gu qun...@blacksesame.com
 主题: 答复: [Elphel-support] 答复: 答复: 答复: 答复: 答复: Re: Quote for 1 NC393-Stereo 
camera
 
 
  
 Hello
   Thank you for your patient to answer my question. But I have some others 
as follow.
 1)How should I make the left and right camera AWB change synchronously? 
The left camera image color is very different with right camera image color. 
Please look at the last email attachment. I followed your advices, and set the 
WB_EN=0 and GAINR/GAING/GAINB = some value, and made the left and right camera 
image WB very close. But it just applies only to one situation. If I change the 
ambient lighting brightness, the GAINR/GAING/GAINB value should be set again. 
 2)How should I make the 

Re: [Elphel-support] 答复: 答复: 答复: 答复: 答复: 答复: 答复: Re: Quote for 1 NC393-Stereo camera

[Elphel Support]

Tao,

OK, will wait for the picture. White balance does not need to change for the 
outdoor (maybe for night city with electrical lights - and I still recommend to 
use presets). You see there are conditions when it is easy to fool AWB, and 
while it may be OK for just a regular camera, you need to know exactly how the 
image is processed to match multiple images.

The AWB algorithm is rather simple. It assumes that the brightest object in the 
scene is white - and in most cases it works. But when there is nothing white in 
the scene - AWB fails. 

With AE you may try to change those values I mentioned earlier.

Andrey

 On Mon, 08 Jan 2018 17:06:43 -0800 Tao 
Zhangtao.zh...@blacksesame.com.cn wrote  

Hi Andrey,
 We will fix the camera on a car. The light condition may change. AWB need to 
adapt to the change. For AE, the scene is normal in the office, there is not 
bright light. But it cannot converge to a stable status. We will attach images 
and videos of those problems later.
  
  Tao Zhang
 章   涛
 
  
   发件人: Elphel Support [mailto:support-list@support.elphel.com] 
 发送时间: 2018年1月9日 4:02
 收件人: Tao Zhang tao.zh...@blacksesame.com.cn; Elphel List 
support-list@support.elphel.com
 抄送: Winston Zhang winston.zh...@blacksesame.com.cn; Elphel Sales | 
Olga Filippova sa...@elphel.com; Qun Gu qun...@blacksesame.com
 主题: Re: [Elphel-support] 答复: 答复: 答复: 答复: 答复: 答复: Re: Quote for 1 NC393-Stereo 
camera
 
 
  
  Tao,
 
 I did not get the attached image to see your problem, but I expect you just 
need to modify the settings. Camera has a flexible control over AWB and AE to 
provide optimal operation for different lighting conditions. Most likely 
problem of of the instability is that there is a bright light source in the 
field of view.
 
 First you need to make AE stable, then set or disable AWB (it only needs to be 
changed when you move from the indoors to outdoors), so if you work outdoors 
you may just set AWB once and then save parameters - that will make image 
matching easier.
 
 For AE you may control:
 1) the AE window (camera will only consider exposure for the selected 
rectangle, ignoring lights outside it.
 2) The fraction of pixels that should have intensity values below certain 
threshold - reduce default value if there are lights in the FOV (especially 
electrical lights that have flicker)
 3) The level (default 250) - target of autoexposure.
 There are some illustrations on the wiki:  
https://wiki.elphel.com/wiki/Autoexposure
 
 Andrey
    On Mon, 08 Jan 2018 01:10:17 -0800 Tao 
Zhangtao.zh...@blacksesame.com.cn wrote  
 
BTW, your stereo AE has oscillation and AWB is not accurate. Do you have 
updated firmware to solve these problems?
  
   Tao Zhang
  章   涛
 
  
   发件人: Winston Zhang 
 发送时间: 2018年1月8日 16:54
 收件人: Oleg support-list@support.elphel.com
 抄送: Elphel Sales | Olga Filippova sa...@elphel.com; Dan Pan 
ad...@blacksesame.com; Tao Zhang tao.zh...@blacksesame.com.cn; 
Qun Gu qun...@blacksesame.com
 主题: 答复: [Elphel-support] 答复: 答复: 答复: 答复: 答复: Re: Quote for 1 NC393-Stereo 
camera
 
 
  
 Hello
   Thank you for your patient to answer my question. But I have some others 
as follow.
 1)How should I make the left and right camera AWB change synchronously? 
The left camera image color is very different with right camera image color. 
Please look at the last email attachment. I followed your advices, and set the 
WB_EN=0 and GAINR/GAING/GAINB = some value, and made the left and right camera 
image WB very close. But it just applies only to one situation. If I change the 
ambient lighting brightness, the GAINR/GAING/GAINB value should be set again. 
 2)How should I make the left and right camera exposure change 
synchronously? The left and right camera exposure at different time and cause 
the image brightness different. So, if I capture the same timestamp frames, the 
frames brightness are so different. I want to do some stereo-match work, but 
all of these get me into trouble.
  

 

  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: andersonnotg...@gmail.com [mailto:andersonnotg...@gmail.com] 代表 Oleg
 发送时间: 2017年12月28日 星期四 3:13
 收件人: Winston Zhang winston.zh...@blacksesame.com.cn
 抄送: Elphel Sales | Olga Filippova sa...@elphel.com; Dan Pan 
ad...@blacksesame.com; Tao Zhang tao.zh...@blacksesame.com.cn; 
Qun Gu qun...@blacksesame.com; elphel support-list 
support-list@support.elphel.com
 主题: Re: [Elphel-support] 答复: 答复: 答复: 答复: 答复: Re: Quote for 1 NC393-Stereo 
camera
  
  Hello,
   
 
  1)How could I get the raw data of camera. Because when I got the rgb data 
from multipart jpeg stream, the image had some color blocks if I amplified 
eight times. I thought it could be caused by image conversion 
compression.(please look at the attachments).

 
  You can switch to JP4 format - it's close to raw.
 
  What I 

[Elphel-support] 答复: 答复: 答复: 答复: 答复: 答复: 答复: Re: Quote for 1 NC393-Stereo camera

[Tao Zhang]

Hi Andrey,
We will fix the camera on a car. The light condition may change. AWB need to 
adapt to the change. For AE, the scene is normal in the office, there is not 
bright light. But it cannot converge to a stable status. We will attach images 
and videos of those problems later.

Tao Zhang
章   涛

发件人: Elphel Support [mailto:support-list@support.elphel.com]
发送时间: 2018年1月9日 4:02
收件人: Tao Zhang ; Elphel List 

抄送: Winston Zhang ; Elphel Sales | Olga 
Filippova ; Qun Gu 
主题: Re: [Elphel-support] 答复: 答复: 答复: 答复: 答复: 答复: Re: Quote for 1 NC393-Stereo 
camera

Tao,

I did not get the attached image to see your problem, but I expect you just 
need to modify the settings. Camera has a flexible control over AWB and AE to 
provide optimal operation for different lighting conditions. Most likely 
problem of of the instability is that there is a bright light source in the 
field of view.

First you need to make AE stable, then set or disable AWB (it only needs to be 
changed when you move from the indoors to outdoors), so if you work outdoors 
you may just set AWB once and then save parameters - that will make image 
matching easier.

For AE you may control:
1) the AE window (camera will only consider exposure for the selected 
rectangle, ignoring lights outside it.
2) The fraction of pixels that should have intensity values below certain 
threshold - reduce default value if there are lights in the FOV (especially 
electrical lights that have flicker)
3) The level (default 250) - target of autoexposure.
There are some illustrations on the wiki: 
https://wiki.elphel.com/wiki/Autoexposure

Andrey
 On Mon, 08 Jan 2018 01:10:17 -0800 Tao 
Zhang> wrote 

BTW, your stereo AE has oscillation and AWB is not accurate. Do you have 
updated firmware to solve these problems?

Tao Zhang
章   涛

发件人: Winston Zhang
发送时间: 2018年1月8日 16:54
收件人: Oleg 
>
抄送: Elphel Sales | Olga Filippova >; 
Dan Pan >; Tao Zhang 
>; Qun Gu 
>
主题: 答复: [Elphel-support] 答复: 答复: 答复: 答复: 答复: Re: Quote for 1 NC393-Stereo camera

Hello
  Thank you for your patient to answer my question. But I have some others 
as follow.

1)How should I make the left and right camera AWB change synchronously? The 
left camera image color is very different with right camera image color. Please 
look at the last email attachment. I followed your advices, and set the WB_EN=0 
and GAINR/GAING/GAINB = some value, and made the left and right camera image WB 
very close. But it just applies only to one situation. If I change the ambient 
lighting brightness, the GAINR/GAING/GAINB value should be set again.

2)How should I make the left and right camera exposure change 
synchronously? The left and right camera exposure at different time and cause 
the image brightness different. So, if I capture the same timestamp frames, the 
frames brightness are so different. I want to do some stereo-match work, but 
all of these get me into trouble.



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: andersonnotg...@gmail.com 
[mailto:andersonnotg...@gmail.com] 代表 Oleg
发送时间: 2017年12月28日 星期四 3:13
收件人: Winston Zhang 
>
抄送: Elphel Sales | Olga Filippova >; 
Dan Pan >; Tao Zhang 
>; Qun Gu 
>; elphel support-list 
>
主题: Re: [Elphel-support] 答复: 答复: 答复: 答复: 答复: Re: Quote for 1 NC393-Stereo camera

Hello,

1)How could I get the raw data of camera. Because when I got the rgb data 
from multipart jpeg stream, the image had some color blocks if I amplified 
eight times. I thought it could be caused by image conversion 
compression.(please look at the attachments).

You can switch to JP4 format - it's close to 
raw.
What I see in the attached images is they have different white balance. And 
also there are overexposed areas which can affect the correct balance.

The white balance is run independently for each sensor - you can try to set it 
so the images look the same and then turn off for both sensors:
a) open the 

Re: [Elphel-support] 答复: 答复: 答复: 答复: 答复: 答复: Re: Quote for 1 NC393-Stereo camera

[Elphel Support]

Tao,

I did not get the attached image to see your problem, but I expect you just 
need to modify the settings. Camera has a flexible control over AWB and AE to 
provide optimal operation for different lighting conditions. Most likely 
problem of of the instability is that there is a bright light source in the 
field of view.

First you need to make AE stable, then set or disable AWB (it only needs to be 
changed when you move from the indoors to outdoors), so if you work outdoors 
you may just set AWB once and then save parameters - that will make image 
matching easier.

For AE you may control:
1) the AE window (camera will only consider exposure for the selected 
rectangle, ignoring lights outside it.
2) The fraction of pixels that should have intensity values below certain 
threshold - reduce default value if there are lights in the FOV (especially 
electrical lights that have flicker)
3) The level (default 250) - target of autoexposure.
There are some illustrations on the wiki: 
https://wiki.elphel.com/wiki/Autoexposure

Andrey
 On Mon, 08 Jan 2018 01:10:17 -0800 Tao 
Zhangtao.zh...@blacksesame.com.cn wrote  

BTW, your stereo AE has oscillation and AWB is not accurate. Do you have 
updated firmware to solve these problems?
  
  Tao Zhang
 章   涛
 
  
   发件人: Winston Zhang 
 发送时间: 2018年1月8日 16:54
 收件人: Oleg support-list@support.elphel.com
 抄送: Elphel Sales | Olga Filippova sa...@elphel.com; Dan Pan 
ad...@blacksesame.com; Tao Zhang tao.zh...@blacksesame.com.cn; 
Qun Gu qun...@blacksesame.com
 主题: 答复: [Elphel-support] 答复: 答复: 答复: 答复: 答复: Re: Quote for 1 NC393-Stereo 
camera
 
 
  
 Hello
   Thank you for your patient to answer my question. But I have some others 
as follow.
  1)How should I make the left and right camera AWB change synchronously? 
The left camera image color is very different with right camera image color. 
Please look at the last email attachment. I followed your advices, and set the 
WB_EN=0 and GAINR/GAING/GAINB = some value, and made the left and right camera 
image WB very close. But it just applies only to one situation. If I change the 
ambient lighting brightness, the GAINR/GAING/GAINB value should be set again. 
  2)How should I make the left and right camera exposure change 
synchronously? The left and right camera exposure at different time and cause 
the image brightness different. So, if I capture the same timestamp frames, the 
frames brightness are so different. I want to do some stereo-match work, but 
all of these get me into trouble.
  
   
 
   
 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: andersonnotg...@gmail.com [mailto:andersonnotg...@gmail.com] 代表 Oleg
 发送时间: 2017年12月28日 星期四 3:13
 收件人: Winston Zhang winston.zh...@blacksesame.com.cn
 抄送: Elphel Sales | Olga Filippova sa...@elphel.com; Dan Pan 
ad...@blacksesame.com; Tao Zhang tao.zh...@blacksesame.com.cn; 
Qun Gu qun...@blacksesame.com; elphel support-list 
support-list@support.elphel.com
 主题: Re: [Elphel-support] 答复: 答复: 答复: 答复: 答复: Re: Quote for 1 NC393-Stereo 
camera
  
  Hello,
   
 
  1)How could I get the raw data of camera. Because when I got the rgb data 
from multipart jpeg stream, the image had some color blocks if I amplified 
eight times. I thought it could be caused by image conversion 
compression.(please look at the attachments).

 
  You can switch to  JP4 format - it's close to raw.
 
  What I see in the attached images is they have different white balance. And 
also there are overexposed areas which can affect the correct balance.
 
   
 
  The white balance is run independently for each sensor - you can try to set 
it so the images look the same and then turn off for both sensors:
 
  a) open the  web interface for each sensor - click on the green circle OR 
 
  b) set WB_EN=0 (also for both channels) in parameters - if you change it 
through a table 
(http://192.168.0.9/parsedit.php?sensor_port=2title=Parameters+for+groups:+whiteBalance+GTAB_RGTAB_GGTAB_GBGTAB_BWB_THRESHWB_PERIODWB_MASKWB_ENWB_WHITELEVWB_WHITEFRACWB_MAXWHITEWB_SCALE_RWB_SCALE_GBWB_SCALE_BGAIN_MINGAIN_MAXGAIN_CTRLGAIN_STEPANA_GAIN_ENABLE)
 then there is a broadcast mask to set the parameter for all sensors at the 
same time - set it to F.
 
   
 
  if I amplified eight times.
  What are the gains and exposure for each sensor?
   
 
   2)The camera temperature has risen quickly, and I could not capture 
images. Because it was so slowly to run the video when the camera had been 
opened for four hours. But If I closed the camera and the temperature dropped 
down, the video was showed normally.

 
  What is the temperature? http://192.168.0.9  Temperature monitor
 
  If it's around 70-80 it's ok (at 90 degrees the camera is forced to shut down)
 
  Also, the camera should reach the steady temperature pretty much in the the 
first 30-60 mins.
 
   
 
  - 

Re: [Elphel-support] 答复: 答复: 答复: 答复: 答复: 答复: Re: Quote for 1 NC393-Stereo camera

[Elphel Support]

Dear Winston,

I did not get email attachment, can you please resend it so I understand what 
is wrong in you setup.

I do not recommend to use white balance for image matching - you may set it 
once, then store settings so the camera will next time boot with the same 
settings - this is what we do for such applications.

The autoexposure daemon is designed to operate independently - in panoramic 
applications cameras pointed in different directions may need very different 
exposure. If autoexposure is unstable you probably just need to modify 
settings, because the goal of the autoexposure algorithm may be different. In 
you case you probably have some bright electrical light that fools the camera.

Here is generally how algorithm works: it maintains exposure so only a certain 
fraction of all pixels will have value above a certain value. For the normal 
good quality outdoor image the fraction of overexposed is set to a very small 
value (like 99.2% pixels should have =250 of 255 value). Such combination 
provide good quality images if there are no bright lights (or sun reflections) 
in the FOV. If there are some, you may want to reduce required "good" (not 
overexposed) pixels to say 98% or 95%, possibly simultaneously reducing the 
required level. There are illustrations on the wiki: 
https://wiki.elphel.com/wiki/Autoexposure .

That will make the camera ignore larger bright lights/reflection and eliminate 
exposure fluctuations.

On the other hand exposure settings as well as gain settings are included in 
each frame Exif header, so the post-processing software can eliminate influence 
of the exposure/gains and gamma correction. When we process jp4 images in 
ImageJ plugin 
(https://git.elphel.com/Elphel/imagej-elphel/blob/master/src/main/java/JP46_Reader_camera.java
 ), the first step is that the JP4 image from the camera is converted to a 
floating-point data with linear intensity scale (gamma conversion is undone), 
and each color gain is reversed too, providing data close to what sensor would 
provide with the same gain settings. Exposure value is also available, so it is 
possible to divide these linear-scaled image by the exposure value to 
compensate variations - that will help image matching.
 
Andrey


 On Mon, 08 Jan 2018 00:54:12 -0800 Winston 
Zhangwinston.zh...@blacksesame.com.cn wrote  

Hello
   Thank you for your patient to answer my question. But I have some others 
as follow.
  1)How should I make the left and right camera AWB change synchronously? 
The left camera image color is very different with right camera image color. 
Please look at the last email attachment. I followed your advices, and set the 
WB_EN=0 and GAINR/GAING/GAINB = some value, and made the left and right camera 
image WB very close. But it just applies only to one situation. If I change the 
ambient lighting brightness, the GAINR/GAING/GAINB value should be set again. 
  2)How should I make the left and right camera exposure change 
synchronously? The left and right camera exposure at different time and cause 
the image brightness different. So, if I capture the same timestamp frames, the 
frames brightness are so different. I want to do some stereo-match work, but 
all of these get me into trouble.
  

 
   
 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: andersonnotg...@gmail.com [mailto:andersonnotg...@gmail.com] 代表 Oleg
 发送时间: 2017年12月28日 星期四 3:13
 收件人: Winston Zhang winston.zh...@blacksesame.com.cn
 抄送: Elphel Sales | Olga Filippova sa...@elphel.com; Dan Pan 
ad...@blacksesame.com; Tao Zhang tao.zh...@blacksesame.com.cn; 
Qun Gu qun...@blacksesame.com; elphel support-list 
support-list@support.elphel.com
 主题: Re: [Elphel-support] 答复: 答复: 答复: 答复: 答复: Re: Quote for 1 NC393-Stereo 
camera
  
  Hello,
   
 
  1)How could I get the raw data of camera. Because when I got the rgb data 
from multipart jpeg stream, the image had some color blocks if I amplified 
eight times. I thought it could be caused by image conversion 
compression.(please look at the attachments).

 
  You can switch to  JP4 format - it's close to raw.
 
  What I see in the attached images is they have different white balance. And 
also there are overexposed areas which can affect the correct balance.
 
   
 
  The white balance is run independently for each sensor - you can try to set 
it so the images look the same and then turn off for both sensors:
 
  a) open the  web interface for each sensor - click on the green circle OR 
 
  b) set WB_EN=0 (also for both channels) in parameters - if you change it 
through a table 
(http://192.168.0.9/parsedit.php?sensor_port=2title=Parameters+for+groups:+whiteBalance+GTAB_RGTAB_GGTAB_GBGTAB_BWB_THRESHWB_PERIODWB_MASKWB_ENWB_WHITELEVWB_WHITEFRACWB_MAXWHITEWB_SCALE_RWB_SCALE_GBWB_SCALE_BGAIN_MINGAIN_MAXGAIN_CTRLGAIN_STEPANA_GAIN_ENABLE)
 

[Elphel-support] Elphel Development Blog: Efficient Complex Lapped Transform Implementation for the Space-Variant Frequency Domain Calculations of the Bayer Mosaic Color Images

[Elphel Development Blog]

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January 8, 2018 2:00 AM


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Efficient Complex Lapped Transform Implementation for the Space-Variant Frequency Domain Calculations of the Bayer Mosaic Color Images
This post continues discussion of the small tile space-variant frequency domain (FD) image processing in the camera, it demonstrates that modulated complex lapped transform (MCLT) of the Bayer mosaic color images requires almost 3 times less computational resources than that of the full RGB color data. 
Contents1 “Small Tile” and “Space Variant”2 Frequency Domain Conversion with the Modulated Complex Lapped Transform2.1 Reversibility of the Modified Discrete Cosine and Sine Transforms 2.2 Space-variant shift and TDAC property3 Implementation of the MCLT for the Monochrome 16×16 Pixel Tiles4 Modulated Complex Lapped Transform for the Bayer Mosaic Color Images4.1 Relation between DCT-IV and DST-IV4.2 Two-dimensional MCLT Symmetries for the Bayer Mosaic Sub-arrays4.3 Implementation of the MCLT for the Bayer Mosaic Pixel Tiles4.4 MCLT Converter for the Bayer Mosaic Tiles Simulation and Comparison to the Software Post-processing results5 Results6 References

 “Small Tile” and “Space Variant”
Why “small tile“? Most camera images have short (up to few pixels) correlation/mutual information span related to the acquisition system properties – optical aberrations cause a single scene object point influence a small area of the sensor pixels. When matching multiple images increase of the window size reduces the lateral (x,y) resolution, so many of the 3d reconstruction algorithms do not use any windows at all, and process every pixel individually. Other limitation on the window size comes from the fact that FD conversions (Fourier and similar) in Cartesian coordinates are shift-invariant, but are sensitive to scale and rotation mismatch. So targeting say 0.1 pixel disparity accuracy the scale mismatch should not cause error accumulation over window width exceeding that value. With 8×8 tiles (16×16 overlapped) acceptable scale mismatch (such as focal length variations) should be under 1%. That tolerance is reasonable, but it can not get much tighter.

What is “space variant“? One of the most universal operations performed in the FD is convolution (also related to correlation) that exploits convolution-multiplication property. Mathematically convolution applies the same operation to each of the points of the source data, so shifted object of the source image produces just a shifted result after convolution. In the physical world it is a close approximation, but not an exact one. Stars imaged by a telescope may have sharper images in the center, but more blurred in the peripheral areas. While close (angularly) stars produce almost the same shape images, the far ones do not. This does not invalidate convolution approach completely, but requires kernel to (smoothly) vary over the input images [1, 2], makes it a space-variant kernel.

Figure 1. Complex Lapped Transform with DCT-IV/DST-IV: time-domain aliasing cancellation (TDAC) property. a) selection of overlapping input subsequences 2*N-long, multiplication by sine window; b) creating N-long sequences for DCT-IV (left) and DST-IV (right); c) (after frequency domain processing) extending N-long sequence using DCT-IV boundary conditions (DST-IV processing is similar); d) second multiplication by sine window; e) combining partial data
 
There is another issue related to the space-variant kernels. Fractional pixel shifts are required for multiple steps of the processing: aberration correction (obvious in the case of the  lateral chromatic aberration), image rectification before matching that accounts for lens optical distortion, camera orientation mismatch and epipolar geometry transformations. Traditionally it is handled by the image rectification that involves re-sampling of the pixel values for a new grid using some type of the interpolation. This process distorts the signal data and introduces non-linear errors that reduce accuracy of the correlation, that is important for subpixel disparity measurements. Our approach completely eliminates resampling and combines integer pixel shift in the pixel domain and delegates the residual fractional pixel shift (±0.5 pix) to the FD, where it is implemented as a cosine/sine phase rotator. Multiple sources of the required pixel shift are combined for each tile, and then a single phase rotation is performed as a last step of pixel domain to FD conversion.

Frequency Domain Conversion with the Modulated Complex Lapped Transform
Modulated Complex Lapped Transform (MCLT)[3] can be used to split input sequence into overlapping fractions, processed separately and then 

[Elphel-support] 答复: 答复: 答复: 答复: 答复: 答复: Re: Quote for 1 NC393-Stereo camera

[Tao Zhang]

BTW, your stereo AE has oscillation and AWB is not accurate. Do you have 
updated firmware to solve these problems?

Tao Zhang
章   涛

发件人: Winston Zhang
发送时间: 2018年1月8日 16:54
收件人: Oleg 
抄送: Elphel Sales | Olga Filippova ; Dan Pan 
; Tao Zhang ; Qun Gu 

主题: 答复: [Elphel-support] 答复: 答复: 答复: 答复: 答复: Re: Quote for 1 NC393-Stereo camera

Hello
  Thank you for your patient to answer my question. But I have some others 
as follow.

1)How should I make the left and right camera AWB change synchronously? The 
left camera image color is very different with right camera image color. Please 
look at the last email attachment. I followed your advices, and set the WB_EN=0 
and GAINR/GAING/GAINB = some value, and made the left and right camera image WB 
very close. But it just applies only to one situation. If I change the ambient 
lighting brightness, the GAINR/GAING/GAINB value should be set again.

2)How should I make the left and right camera exposure change 
synchronously? The left and right camera exposure at different time and cause 
the image brightness different. So, if I capture the same timestamp frames, the 
frames brightness are so different. I want to do some stereo-match work, but 
all of these get me into trouble.



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: andersonnotg...@gmail.com 
[mailto:andersonnotg...@gmail.com] 代表 Oleg
发送时间: 2017年12月28日 星期四 3:13
收件人: Winston Zhang 
>
抄送: Elphel Sales | Olga Filippova >; 
Dan Pan >; Tao Zhang 
>; Qun Gu 
>; elphel support-list 
>
主题: Re: [Elphel-support] 答复: 答复: 答复: 答复: 答复: Re: Quote for 1 NC393-Stereo camera

Hello,

1)How could I get the raw data of camera. Because when I got the rgb data 
from multipart jpeg stream, the image had some color blocks if I amplified 
eight times. I thought it could be caused by image conversion 
compression.(please look at the attachments).

You can switch to JP4 format - it's close to 
raw.
What I see in the attached images is they have different white balance. And 
also there are overexposed areas which can affect the correct balance.

The white balance is run independently for each sensor - you can try to set it 
so the images look the same and then turn off for both sensors:
a) open the web interface for each 
sensor 
- click on the green circle OR
b) set WB_EN=0 (also for both channels) in 
parameters - if you 
change it through a table (http://192.168.0.9 > Parameter Editor > select 
whiteBalance > View/Edit 
Current)
 then there is a broadcast mask to set the parameter for all sensors at the 
same time - set it to F.

if I amplified eight times.
What are the gains and exposure for each sensor?

2)The camera temperature has risen quickly, and I could not capture images. 
Because it was so slowly to run the video when the camera had been opened for 
four hours. But If I closed the camera and the temperature dropped down, the 
video was showed normally.

What is the temperature? http://192.168.0.9 > Temperature monitor
If it's around 70-80 it's ok (at 90 degrees the camera is forced to shut down)
Also, the camera should reach the steady temperature pretty much in the the 
first 30-60 mins.

- what is the image quality?
- what are the exposure times? you can try limiting exposure time. The default 
fps is 10 - so, It will get slow if exposure times are >100ms.
- is the camera and the pc the only devices in the network? camera connected 
directly to PC vie cable?
- connect to the camera via ssh and check cpu load:
$ ssh root@192.168.0.9
root@elphel393:~# htop
then click on CPU% table header.
- your PC's cpu load? If you are watching from the browser - it might not be 
able to handle the streams as well.

Best regards,
Oleg Dzhimiev
Electronics Engineer
phone: +1 801 783  x124
Elphel, Inc.
___
Support-list mailing list
Support-list@support.elphel.com

[Elphel-support] 答复: 答复: 答复: 答复: 答复: 答复: Re: Quote for 1 NC393-Stereo camera

[Winston Zhang]

Hello
  Thank you for your patient to answer my question. But I have some others 
as follow.

1)How should I make the left and right camera AWB change synchronously? The 
left camera image color is very different with right camera image color. Please 
look at the last email attachment. I followed your advices, and set the WB_EN=0 
and GAINR/GAING/GAINB = some value, and made the left and right camera image WB 
very close. But it just applies only to one situation. If I change the ambient 
lighting brightness, the GAINR/GAING/GAINB value should be set again.

2)How should I make the left and right camera exposure change 
synchronously? The left and right camera exposure at different time and cause 
the image brightness different. So, if I capture the same timestamp frames, the 
frames brightness are so different. I want to do some stereo-match work, but 
all of these get me into trouble.



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: andersonnotg...@gmail.com [mailto:andersonnotg...@gmail.com] 代表 Oleg
发送时间: 2017年12月28日 星期四 3:13
收件人: Winston Zhang 
抄送: Elphel Sales | Olga Filippova ; Dan Pan 
; Tao Zhang ; Qun Gu 
; elphel support-list 
主题: Re: [Elphel-support] 答复: 答复: 答复: 答复: 答复: Re: Quote for 1 NC393-Stereo camera

Hello,

1)How could I get the raw data of camera. Because when I got the rgb data 
from multipart jpeg stream, the image had some color blocks if I amplified 
eight times. I thought it could be caused by image conversion 
compression.(please look at the attachments).

You can switch to JP4 format - it's close to 
raw.
What I see in the attached images is they have different white balance. And 
also there are overexposed areas which can affect the correct balance.

The white balance is run independently for each sensor - you can try to set it 
so the images look the same and then turn off for both sensors:
a) open the web interface for each 
sensor 
- click on the green circle OR
b) set WB_EN=0 (also for both channels) in 
parameters - if you 
change it through a table (http://192.168.0.9 > Parameter Editor > select 
whiteBalance > View/Edit 
Current)
 then there is a broadcast mask to set the parameter for all sensors at the 
same time - set it to F.

if I amplified eight times.
What are the gains and exposure for each sensor?

2)The camera temperature has risen quickly, and I could not capture images. 
Because it was so slowly to run the video when the camera had been opened for 
four hours. But If I closed the camera and the temperature dropped down, the 
video was showed normally.

What is the temperature? http://192.168.0.9 > Temperature monitor
If it's around 70-80 it's ok (at 90 degrees the camera is forced to shut down)
Also, the camera should reach the steady temperature pretty much in the the 
first 30-60 mins.

- what is the image quality?
- what are the exposure times? you can try limiting exposure time. The default 
fps is 10 - so, It will get slow if exposure times are >100ms.
- is the camera and the pc the only devices in the network? camera connected 
directly to PC vie cable?
- connect to the camera via ssh and check cpu load:
$ ssh root@192.168.0.9
root@elphel393:~# htop
then click on CPU% table header.
- your PC's cpu load? If you are watching from the browser - it might not be 
able to handle the streams as well.

Best regards,
Oleg Dzhimiev
Electronics Engineer
phone: +1 801 783  x124
Elphel, Inc.
___
Support-list mailing list
Support-list@support.elphel.com
http://support.elphel.com/mailman/listinfo/support-list_support.elphel.com