BUG: Totally BLACK image is detected as motion

I have 6 DCS-900 network cameras. Several times per day, a few of them (not all at the same time) decide to return a completely black image (unknown why, camera hardware bug???). The image is totally black. This is NOT your gray image when connectivity is lost. Connectivity is good, pings OK, and within 30 seconds or so, normal processing and normal images start to work again. When this black image is returned by the camera, the motion detection logic notes this as a motion event and starts high-speed recording. When the correct normal image eventually does appear, the box (because of option "locate on") is drawn around then entire image (where it used to be completely black). BUG ?? If you see that an image is totally and instantly completely black, maybe you should continue comparing and NOT declare it as a motion event if the picture soon returns to normal. Comparing the last pre-black image with the first post-black image would show that no motion had occurred. I think of this as a bug since it falsely triggers this as an event.

Test case

random

previously submitted as a "Support Request" but no one answered it

Environment

Motion version:	3.2.4 snap 5
ffmpeg version:	not used
Shared libraries:	ffmpeg, mysql, postgresql
Server OS:	RedHat 7.1 kernel 2.4.20-28.7

-- GregSwift - 26 Jan 2006

Follow up

It is difficult to repair a broken camera. When dark dressed person passes by my cameras I would not want Motion to ignore the motion that should be detected.

There are features in Motion that can prevent Motion detection when a certain amount of Motion is detected. Additionally there are features that prevents Motion being detected unless several pictures in a row contain Motion. Going from completely OK to completely black in one frame can be filtered out with the right settings.

See ConfigOptionLightswitch and ConfigOptionMinimumMotionFrames. In fact read carefully the entire section MotionDetectionSettings. There are plenty of handles to turn.

-- KennethLavrsen - 26 Jan 2006

Fix record

Thank you for your prompt reply. I have read those items and will read them again. Maybe I was not clear enough in my description of the problem. It is not a partially black image or a blackly clothed person, it is absolute total black with no speckles or bad quality, 100% solid black. The image typically returns to normal in about four or five seconds, but I do not want to have to change the motion detection delay to that long (ala ConfigOptionMinimumMotionFrames), but I will try the ConfigOptionLightswitch idea.

If the camera changes from picture to dark from one frame to the next a minimum_motion_frames of 2 or 3 should do it. -- KennethLavrsen - 29 Jan 2006