How well has Sentry worked for me?

quest100

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My system has 10 cameras connected to Sentry and set to send email alerts. For each of these cameras I have BI set up to detect any motion (no Zones) above 100 pixels and 5 of these cameras also have audio triggers turned on. During the last 10 days I have received

30,000 motion triggers
After passing through Sentry I received 1697 email alerts. Of these
1,178 email alerts where Sentry correctly marked in the image as a person,
518 email alerts where Sentry incorrectly marked something as a person,
46 audio alerts which Sentry does not process and passes through,
302 alerts had a small image, no person and had no Sentry outline, and
83 alerts had a large image, no person, and had no Sentry outline.

Now let me try to explain what the categories above mean. First, here is a daily summary image as returned by Sentry from one of my cameras:

HLWAAE-B_CR_dailysummary.jpg

Most of the blue boxes contain a person. As I understand it, BI passes one image per trigger to Sentry which processes the image and returns the coordinates of one or more boxes where it detects a person. A correctly processed image as seen in the email alert:

CR.20190920_183758_1857696.jpg

My first question is why is the image size reduced? The camera is 1080P, BI was instructed to send the image at 100%, but the image is scaled to contain 480 pixels. My 12MP camera (3,000 x 4,000 pixels) also gets reduced to 480 pixels vertically. Is this BI, BI's interaction with Sentry, or Sentry? The images show up in BI's clip list with the <S> icon as expected.

The images that Sentry misidentified as a person were usually a dog (especially at night) in the backyard or a car on the street:

CR.20190911_171847_143271310.jpg

Many of the bad email alerts contain the same scaled image but without the Sentry box outlines anything:

CR.20190920_150640_179612988.jpg

I am guessing that Sentry is not responding in time before BI decides to send out its email alert. Any one know if the real explanation? These images show up in BI's clip list without any Sentry icon.

Occasionally the email alert contains a full scale image (1080 or 3000 pixels vertically). When this happens there is never a box outlined by Sentry and only one of the 83 images happens contained a person:

CR.20190920_090142_92584705.jpg

So my third question is why the occasional full size image? My guess is that Sentry never responded. Even more curious is the this image does not show up at all in BI's clip list. The nearest clips are more than a minute earlier or later.


Overall I am happy with Sentry. It is much better than attempting to set up triggers that filter out clouds, cars, and wind motion.

My only real concern is: why all the alert images with no Sentry processing. It is manageable now but I am afraid it is a symptom of Sentry getting overloaded and possibly getting much worse in the future. This afternoon, over a period of 70 minutes, I had a sequence of 140 alerts returned with no persons and no Sentry boxes outlining anything.

----
Dean
 

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quest100

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I decided to look more closely at the false positive alerts where no Sentry box was drawn and a full size image appears in the email alert. I had a string of 14 such alerts this morning between 9:00 and 9:03 AM. Again, nothing appears in BI's clip list during this time. But when I happened to look at the timeline, most of my cameras were not recording during that 3 minute period. Six cameras out of 15 were recording. It did not seem to matter whether a particular camera was recording or not - some recording cameras and some non-recording cameras were giving the same false positives.

Looking further I noticed that many, but not all of the full size alert images and recording gaps occurred at 9 AM. I looked at BI's status messages and found nothing that indicated a problem or any other unusual messages within 30 minutes of this time period.

While looking at the status messages a new message appeared that I had never seen before - "Sentry: 15s timeout". Shortly thereafter the message disappeared from the message window. When I read the help file more closely I saw that any messages that are identical up to a colon will be rolled up and the count increased.

Thus all messages such as
Sentry: alert cancelled
Sentry: 15s timeout
Sentry: Box <coordinates>
all get rolled up into one message with the count increased. Since the cancelled messages are much more common that the others, only alert cancelled remains in the message window. It seems to me that Sentry aught to distinguish these messages. I would suggest removing the colon from the cancelled and timeout messages and putting the colon before the coordinates in the Box messages. No idea if other types of Sentry messages ever appear.

After learning the implications of the messages being rolled up I turned on the saving of the log file. Luckily no message rollup occurs in the saved file and I see each message. What does the number mean in the first column of the file?

In another day or two I will check the file and see if anything appears near the time some cameras stop recording. Hopefully I will soon know if the cause is in BI, my hard disks, or somewhere else in Windows.
 

quest100

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I found the cause of the recording gap a 9 AM - I had set the database to be compacted/repaired each day at 9. Never realized that the xompacting would take 3 minutes or that it would result in no recording during this time. It took me some time to figure this out. First I looked at the Windows log files and then started going through anything in BI that I thought could cause this. It was probably my third lap through before I noticed this particular setting.

I wonder if the compacting would have the same effect (no recording) if it was set for later in the hour. I have 15 cameras set to record continuously and they all start a new file on the hour. I am going to switch the compacting time to 9:11 in the morning and see if I still lose the recording for around 3 minutes. I am wondering if once compacting that a new clip file can not start.

Is the compacting/repair of the database needed? Would switching from a hard disk to a solid state disk speed it up? How much? What will happen when I decide to add another 10 TB disk to increase clip storage from 10 days to 20 days?
 

fenderman

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I found the cause of the recording gap a 9 AM - I had set the database to be compacted/repaired each day at 9. Never realized that the xompacting would take 3 minutes or that it would result in no recording during this time. It took me some time to figure this out. First I looked at the Windows log files and then started going through anything in BI that I thought could cause this. It was probably my third lap through before I noticed this particular setting.

I wonder if the compacting would have the same effect (no recording) if it was set for later in the hour. I have 15 cameras set to record continuously and they all start a new file on the hour. I am going to switch the compacting time to 9:11 in the morning and see if I still lose the recording for around 3 minutes. I am wondering if once compacting that a new clip file can not start.

Is the compacting/repair of the database needed? Would switching from a hard disk to a solid state disk speed it up? How much? What will happen when I decide to add another 10 TB disk to increase clip storage from 10 days to 20 days?
You can turn it off and run it manually if you have an issue. running the database on an ssd is recommended and will make the compacting much quicker. You should run windows and bi on the ssd as well. Huge speed improvements.
 

TL1096r

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How do you count the amount of cars passing? That is interesting.
 

varghesesa

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My system has 10 cameras connected to Sentry and set to send email alerts. For each of these cameras I have BI set up to detect any motion (no Zones) above 100 pixels and 5 of these cameras also have audio triggers turned on. During the last 10 days I have received

30,000 motion triggers
After passing through Sentry I received 1697 email alerts. Of these
1,178 email alerts where Sentry correctly marked in the image as a person,
518 email alerts where Sentry incorrectly marked something as a person,
46 audio alerts which Sentry does not process and passes through,
302 alerts had a small image, no person and had no Sentry outline, and
83 alerts had a large image, no person, and had no Sentry outline.

Now let me try to explain what the categories above mean. First, here is a daily summary image as returned by Sentry from one of my cameras:

View attachment 47616

Most of the blue boxes contain a person. As I understand it, BI passes one image per trigger to Sentry which processes the image and returns the coordinates of one or more boxes where it detects a person. A correctly processed image as seen in the email alert:

View attachment 47617

My first question is why is the image size reduced? The camera is 1080P, BI was instructed to send the image at 100%, but the image is scaled to contain 480 pixels. My 12MP camera (3,000 x 4,000 pixels) also gets reduced to 480 pixels vertically. Is this BI, BI's interaction with Sentry, or Sentry? The images show up in BI's clip list with the <S> icon as expected.

The images that Sentry misidentified as a person were usually a dog (especially at night) in the backyard or a car on the street:

View attachment 47620

Many of the bad email alerts contain the same scaled image but without the Sentry box outlines anything:

View attachment 47622

I am guessing that Sentry is not responding in time before BI decides to send out its email alert. Any one know if the real explanation? These images show up in BI's clip list without any Sentry icon.

Occasionally the email alert contains a full scale image (1080 or 3000 pixels vertically). When this happens there is never a box outlined by Sentry and only one of the 83 images happens contained a person:

View attachment 47619

So my third question is why the occasional full size image? My guess is that Sentry never responded. Even more curious is the this image does not show up at all in BI's clip list. The nearest clips are more than a minute earlier or later.


Overall I am happy with Sentry. It is much better than attempting to set up triggers that filter out clouds, cars, and wind motion.

My only real concern is: why all the alert images with no Sentry processing. It is manageable now but I am afraid it is a symptom of Sentry getting overloaded and possibly getting much worse in the future. This afternoon, over a period of 70 minutes, I had a sequence of 140 alerts returned with no persons and no Sentry boxes outlining anything.

----
Dean
Amazing analysis Dean. Answers below:

"Most of the blue boxes contain a person. As I understand it, BI passes one image per trigger to Sentry which processes the image and returns the coordinates of one or more boxes where it detects a person."

-- Correct

"My first question is why is the image size reduced? The camera is 1080P, BI was instructed to send the image at 100%, but the image is scaled to contain 480 pixels. My 12MP camera (3,000 x 4,000 pixels) also gets reduced to 480 pixels vertically. Is this BI, BI's interaction with Sentry, or Sentry?"

-- Sentry AI does no image processing. We only send back bounding boxes (bbx) highlighting areas of interest. Blue Iris draws the bbxs and scales the images. My assumption is BI scales image for SMS and/or email constraints, but not sure.

"I am guessing that Sentry is not responding in time before BI decides to send out its email alert. Any one know if the real explanation? These images show up in BI's clip list without any Sentry icon."

-- If no icons are displayed on the clip list that usually means BI timed out before the Sentry response. On occasion, errors can also occur which would result in no icons. You would need to check the logs to really know if a timeout or error condition resulted in no icon.

"So my third question is why the occasional full size image? My guess is that Sentry never responded. Even more curious is the this image does not show up at all in BI's clip list. The nearest clips are more than a minute earlier or later."

-- I have no idea here. Very odd. This would be a BI question.

"My only real concern is: why all the alert images with no Sentry processing. It is manageable now but I am afraid it is a symptom of Sentry getting overloaded and possibly getting much worse in the future. "

-- We're on AWS so in theory, timeouts should never happen with auto-scaling. Our dev-ops team is always tweaking and improving the scaling parameters so long term... service should never get worse.

-- Sam from Sentry
 

quest100

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You can turn it off and run it manually if you have an issue. running the database on an ssd is recommended and will make the compacting much quicker. You should run windows and bi on the ssd as well. Huge speed improvements.
It's amazing what's in the manual - once you know where to look. After realizing the gap was caused by compacting the database, letting things gel for a day, and your mention of manually compacting, I searched for database in the manual (I don't remember BI4 having a searchable manual) and found where it talks about not recording during DB compaction. I would have thought that triggers and email alerts would have also stopped, but evidently not.

I just tried manually starting a DB compaction. No loss of recordings but still getting email alerts that contain a full size image but no person, no Sentry boxes indicating a person, and no triggered alerts in the clip list. It appears that the continuous recording is lost only when DB compaction and new clip files occur at the same time.

I plan next year to upgrade the C drive to a SSD, but for now everything except the clips is on a spinning hard drive. The clips are on a 10TB purple drive. I have not seen any problems til now with the hard disk. Other than compaction what get sped up? I am willing to live with slight delays in examining triggered clips.

----
Dean
 

quest100

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How do you count the amount of cars passing? That is interesting.
I don't. When I mentioned cars it was because sometimes Sentry mistakes a car for a person. Mainly this happens when a light colored car passes behind a branching tree trunk in our front yard.

----
Dean
 

quest100

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"My first question is why is the image size reduced? The camera is 1080P, BI was instructed to send the image at 100%, but the image is scaled to contain 480 pixels. My 12MP camera (3,000 x 4,000 pixels) also gets reduced to 480 pixels vertically. Is this BI, BI's interaction with Sentry, or Sentry?"

-- Sentry AI does no image processing. We only send back bounding boxes (bbx) highlighting areas of interest. Blue Iris draws the bbxs and scales the images. My assumption is BI scales image for SMS and/or email constraints, but not sure.

-- Sam from Sentry
I did some more digging and it you are right, the reduced size has nothing to do with Sentry and instead is caused by my switching to BI5.

I installed BI5 on Sept 2. Looking at my old email alerts I see that mid day the alert images changed from full size to 480 pixels. It wasn't until Sept 3 that I first turned on Sentry. The first email alert with a red Sentry box drawn on it occurred mid day - one day after I started receiving scaled images. My apologies to Sentry for blaming you. I will contact BI and ask for an explanation.

----
Dean
 

TL1096r

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I don't. When I mentioned cars it was because sometimes Sentry mistakes a car for a person. Mainly this happens when a light colored car passes behind a branching tree trunk in our front yard.

----
Dean
Thank you. sorry i don't mean to take away and only add but is there a way to count cars with sentry?
 

varghesesa

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Thank you. sorry i don't mean to take away and only add but is there a way to count cars with sentry?
We have not activated vehicle detection yet, but when we do so, you would get alerts similar to human detection. You will easily be able to count alerts with vehicle detected in the clip list but it will not be a true count. For example, you would only get one alert per clip and the clip may actually have 1+ cars in the image.

What's the use case for counting cars?

-- Sam from Sentry
 

TL1096r

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We have not activated vehicle detection yet, but when we do so, you would get alerts similar to human detection. You will easily be able to count alerts with vehicle detected in the clip list but it will not be a true count. For example, you would only get one alert per clip and the clip may actually have 1+ cars in the image.

What's the use case for counting cars?

-- Sam from Sentry
I am not sure but thought it would be interested if cars are logged in this manner for reference later. Yes I suppose detection alerts could work and manually count detection of just cars. You can isolate detection? I am not familiar with sentry and not sure if there is any DIY/REVIEWS to see how it looks but that would be great if they release it as it would make me more willing to buy it for BI. It is so inexpensive I probably could just buy it but seeing it first would make it easier.

I suppose if you live on a busy street and you want the count to see amount of cars driving by without a notifications every time it does. This might help you see if there is a detour or something going on with increase amount of cars. I mean pointless maybe but an idea.
 

varghesesa

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I am not sure but thought it would be interested if cars are logged in this manner for reference later. Yes I suppose detection alerts could work and manually count detection of just cars. You can isolate detection? I am not familiar with sentry and not sure if there is any DIY/REVIEWS to see how it looks but that would be great if they release it as it would make me more willing to buy it for BI. It is so inexpensive I probably could just buy it but seeing it first would make it easier.

I suppose if you live on a busy street and you want the count to see amount of cars driving by without a notifications every time it does. This might help you see if there is a detour or something going on with increase amount of cars. I mean pointless maybe but an idea.
The service is try & buy. If/when you activate the service, it is active for 20 days with no questions asked.

-- Support
 

quest100

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I just tried manually starting a DB compaction. No loss of recordings but still getting email alerts that contain a full size image but no person, no Sentry boxes indicating a person, and no triggered alerts in the clip list. It appears that the continuous recording is lost only when DB compaction and new clip files occur at the same time.
----
Dean
After a couple of days of automatic database compaction at 9:19 while new clips start on the hour, I no longer see any breaks in the recordings. BUT I still get full size images that have not been processed by Sentry in the alert emails and no alerts in the clip list.

——
Dean
 

joshwah

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Hi Dean, did you get a response from BI as to why the images are being cropped prior to being sent to Sentry? is it a setting which can be tweaked?
 

spammenotinoz

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Sentry needs more than 1 frame to improve accuracy. eg: if I walk towards my house with a flashlight, the frame sent to Sentry doesn't have me, it has the flashlight and doesn't flag the image.
A ball is thrown on the lawn, again the ball seems to be the trigger and not the person that follows afterwards (no sentry detection)
Cars arriving and person gets out. The animated GIF sent to my phone shows the person, but sentry just sees the car (no sentry detection)

Perhaps my end trigger is set too high? (currently 15 seconds)

Any tips to improve accuracy under the above conditions?
 

varghesesa

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Sentry needs more than 1 frame to improve accuracy. eg: if I walk towards my house with a flashlight, the frame sent to Sentry doesn't have me, it has the flashlight and doesn't flag the image.
A ball is thrown on the lawn, again the ball seems to be the trigger and not the person that follows afterwards (no sentry detection)
Cars arriving and person gets out. The animated GIF sent to my phone shows the person, but sentry just sees the car (no sentry detection)

Perhaps my end trigger is set too high? (currently 15 seconds)

Any tips to improve accuracy under the above conditions?
Good observation. This is a known limitation with our 1.0 integration. We plan to take 3 frames per event in the next release which we are almost ready to share with BI. We plan to take frames at the MAKEtime setting, +1s, +2s. Another user suggested providing a visual in the clip or UI (TBD) as to which frame is sent to Sentry to help users adjust the MAKE time easily based on their scenario.

-- Sam from Sentry
 
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