Scene color/saturation changes with motion?

[Ri22o]

This isn't the end of the world to find a fix for, but just curious why the scene will be a little washed out/dull until any motion is in the FOV and then the saturation/color will change. Settings are basic for Day: typical exposure, low gain, no Backlight, WB set to Outdoor.

Z12E-S2

Below is the same scene, 8 seconds apart. It starts dull, when there is motion it brightens up, and then it goes back to dull. I may pull the footage and post the video so you can see it go through the range.

 

[wittaj]

I have noticed that to on occasion.

I think it is a result of the the camera zoomed in, so the aperture is smaller and thus less light is allowed in, so any change to gain or shutter speed can have a bigger effect.

The first image appears to be some chromatic aberration going on and that can happen in some field of views that causes some areas to appear purple or purple fringing on edges of objects and it gives that red/blue or green/purple color shifts you see here. Usually I will see it on cameras with high zoom.

Then you get an object, in that case, a person that is light skinned wearing light clothes, and the camera adjusts to that additional contrasting white to the background. I suspect her walking by drops the gain value and then eliminates the washed-out effect.

I will notice that with my LPR camera on white and dark cars. I have been able to minimize it by giving the camera a smaller range for gain to work in. Instead of say 0-45 I have done 40-45 as an example.

 

[biggen]

CBR? VBR?

 

[Ri22o]

CBR? VBR?

CBR 10240

 

[Ri22o]

I have noticed that to on occasion.

I think it is a result of the the camera zoomed in, so the aperture is smaller and thus less light is allowed in, so any change to gain or shutter speed can have a bigger effect.

The first image appears to be some chromatic aberration going on and that can happen in some field of views that causes some areas to appear purple or purple fringing on edges of objects and it gives that red/blue or green/purple color shifts you see here. Usually I will see it on cameras with high zoom.

Then you get an object, in that case, a person that is light skinned wearing light clothes, and the camera adjusts to that additional contrasting white to the background. I suspect her walking by drops the gain value and then eliminates the washed-out effect.

I will notice that with my LPR camera on white and dark cars. I have been able to minimize it by giving the camera a smaller range for gain to work in. Instead of say 0-45 I have done 40-45 as an example.

I'm not too concerned with it since the capture is usable, but was just curious. I also don't notice it with my LPRs since they just stare at asphalt all day and can't get any greyer.

Here is the video.

 

[wittaj]

Yep, that is the gain adjusting as she walks by and the change in gain is changing the color

 

[bigredfish]

Agree, a number of mine react similarly. Even in manual mode they will change Gain and ?exposure when they get input the feel need it.

Assume you’re not running WDR or SSA backlight? That will do it also

 

[Ri22o]

Agree, a number of mine react similarly. Even in manual mode they will change Gain and ?exposure when they get input the feel need it.

Assume you’re not running WDR or SSA backlight? That will do it also

Nope, backlight is off.

 

[samplenhold]

There seems to be a focus change also.

 

[guykuo]

I would actually more expect this is a side effect of white balance being shifted. Notice how the color of white differs between the two scenes. When white point shifts, the scene colors can shift dramatically in hue and saturation. The amount and direction of shift depends on both the original RGB color and how the various RGB gains are readjusted by the camera. Is white balance set to auto? The only white balance setting that I would bet remains constant despite changing scene would be manual. Natural and outdoor probably shift the least, while auto can vary things quite a bit.

 

[Ri22o]

WB set to Outdoor.

 

[Alaska Country]

Noticed a similar issue with a Dahua HFW-5442E-Z4E-S2 (8-32mm zoom) camera. When a vehicle would come across the field of view the image would bloom and return to normal brightness when the vehicle was gone.

This camera is using the shutter set for 'customized range'. Setting were 0 - 6 for the shutter and gain 0 - 40. Also noticed that the shutter settings had the greatest effect on the blooming image.

New settings that solved the issue for daytime:
Shutter 6 - 10
Gain 0 - 65
No nighttime data available at this time.
Note: gain was increased to make up for loss of shutter range.

In my case, if the shutter was set at 4 - 10 (1/250 sec - 1/100 sec) then the issue would again be present, but at 6 - 10 it would not. The slower shutter at 10 (1/100 sec) did not effect the issue. But at 4 (1/250 sec) the faster shutter speed did.

Overall, try changing the faster shutter to one that is slower and see if this will change your outcome. Even 6 - 6 could work but maybe too limited in range for your application. i.e. basically a fixed shutter speed.

Update

Another contributing factor is the setting for "Exposure Comp". If set too high the blooming will once again appear as evening approaches (less light).

Noticed that a setting above 10 would exacerbate the issue. Thus have settled on a setting of 6 for "Exposure Comp".

When "Exposure Comp" is reduced, the image may become too dark. One fix is to increase "Iris". In this example the setting was 19 and was increased to 29.

This is an isolated issue as other Dahua cameras all perform without this problem. This one camera, because of the FOV and lighting conditions requires this special setup.

Exposure settings currently in use for day mode are:

Shutter: 6 - 10
Gain: 0 - 75
Iris: 29
Exposure Comp: 6
Advanced 3D: 20
Advanced 2D: 0