
Density raises $51M Series C led by Kleiner Perkins - jordanmessina
https://www.density.io/blog/kleiner/
======
heyflyguy
I have to admit, more and more I read about things on HN and just reason "ah
this is tech beyond my grasp, and it makes sense to someone somewhere but not
me". Lots of developer tools for languages I've not heard of or libraries that
seem so remote and arcane I wonder who is using them.

Now in this case, it is solving a real problem, with a clear way to make
money. Go Density Go.

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afar
Thank you. Fwiw, our eng team has deeply benefited from all those dev tools
and libraries. The stack to result in real-time, accurate count is nuts. I
think one of our devs, Gus, was on the thread. Maybe he can weigh in.

~~~
guscost
Right now our production backend relies on Postgres, Django, Kafka, Docker,
Nomad, Celery (yes, those queues probably should be folded back into Kafka
eventually), and lots of other open-source tech. I'm not sure if I should
share much, and can't talk in depth anyway, about the embedded stack. And then
there are the tools for developing the algorithm, and custom systems for
assembly/test/pack in Syracuse.

Our web application is mostly TypeScript, React, RxJS.

~~~
heyflyguy
The hardware is yours?

~~~
guscost
Yes, designed in-house by some very talented colleagues.

~~~
heyflyguy
Nice job, that ain't easy.

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realtalk_sp
Do you worry that you're taking money at a valuation that's predicated on
artificially and transiently elevated demand? It doesn't sound like you have a
business compatible with the VC hyper-growth model, outside of the present
extraordinary circumstances.

It also feels intuitively like many person counting use cases are
satisfactorily addressed by far simpler and lower cost heuristics such as, for
example, Google lining up device 'throughput' with lat/long and business
records. In fact, I just used their estimate to time my visit to the DMV and
it worked perfectly.

Admittedly, it may just be that I'm not creative enough to envision
sustainable, valuable use cases for this. But if you've been around 6 (?)
years and just took $51M in Series C without being significantly diluted, KP
is presumably assigning you at least a $250M valuation and possibly a lot
higher. After accounting for terms like e.g. liquidation preference, the
economic picture of Density could easily be a house of cards.

~~~
afar
Lower cost systems like Google's Popular Times, are not as accurate as they
seem. The next time you see a graph on google, you'll notice there's no
y-axis. It's a clever way to look like actuals when it's relative to itself.
Also we have units in many GPT locations. They're not accurate. On the vc
returns thing ¯\\_(ツ)_/¯ We'll see.

~~~
nobbis
How does the accuracy of your system compare to ARKit’s people/skeleton
tracking with the LiDAR Scanner in the new iPad Pro?

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dtertman
I remember when this was a Show HN, it was my first comment to say that the
homepage didn't work for me in an old version of Firefox (and the developers
reached out, thanked me for the report, and fixed the problem).

[https://news.ycombinator.com/item?id=9878597](https://news.ycombinator.com/item?id=9878597)

Now so many businesses needs to count capacity, and they're perfectly
positioned with 5 years of experience in the space. Amazing foresight (and/or
a bit of luck).

~~~
afar
dtertman! Those were awesome questions (same cofounder here). I read a thing a
while back as a startup, your job is to survive long enough for the market to
need you. Great talking to you 5 years later.

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oli_b
From density.io:

> Unlike other systems, Density is anonymous at source. We can't fingerprint
> or track you if we wanted to.

I wonder how true this statement is, given how accurately we can now identify
people based on just their walking gait – see "Human Gait Recognition Based on
Gait Energy" paper[1].

The 'sensor' view on density.io that attempts to illustrate this point appears
to convey just as much as the sample images in the paper.

[1]
[https://ijsr.net/archive/v5i11/ART20163043.pdf](https://ijsr.net/archive/v5i11/ART20163043.pdf)

~~~
afar
We get this question from time to time. It may be possible with some systems
but it's not feasible at our resolution. You can see more of our depth data
here -- [https://medium.com/density-inc/ai-is-not-magic-its-manual-
la...](https://medium.com/density-inc/ai-is-not-magic-its-manual-labor-math-
how-we-built-an-accurate-people-counter-e00408ea30de)

~~~
oli_b
I'll have to take your word for it – I'm curious if you have tried it though.
I can certainly imagine that it might be feasible (even at lower resolutions)
with enough stirring of the 'linear algebra pile'.

Not meaning to rain on your parade though – congratulations on a great idea!

~~~
afar
No rain! It's a great callout. We'll see what we can do if for no other reason
than to understand risk.

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gk1
This is a great example of taking an innovation and positioning it as a
solution to a real, painful, and _timely_ business problem.

Many startups in their place try to come up with some original messaging and
as a result overcomplicate everything. Density keeps it simple: "Count
people."

~~~
afar
I've lost track of the number of times we've said, "well, we count people" and
thought... god this must be boring for other people.

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mooktakim
I don't understand why this can't already be done with CCTV cameras. There's
obvious privacy concerns, but we already have CCTV. We are already recorded.
Why do you need a special device when you could just count people on camera.

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Disruptive_Dave
Oh man, I remember about 10 years I got so annoyed with my buys-ass gym and
having to wait in line to use a machine that I came up with the idea to track
real-time gym attendance and machine usage. It was going to be called
WaitLift. It never went further than that awesome name.

~~~
afar
That is an exceptional name. If you still want to build it, we have a real-
time API. Love supporting apps :) (Density cofounder here)

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shard
I wonder how much more accurate this solution is compared to a simple IR beam
across the entry. Is the extra HW and SW complexity needed to implement a
computer vision solution worth the increase accuracy? I suppose the answer
would depend on the use case. Mom-and-pop shops might only need an IR beam, if
that, while megacorps that optimize costs down to the penny might have use for
exact customer trends so they can decide how much human workforce and/or
automation they need.

~~~
jartelt
Basic IR beam solutions cannot tell the difference between someone going in
the store vs someone going out, so keeping a real-time count of occupancy is
difficult (or impossible). They also struggle with two people going through a
doorway at the same time (counted as one entry vs 2).

~~~
shard
A two beam setup would allow differentiation between entering and exiting of
single clients. Then the question comes down to how often do 2+ people cross
the beams at once, and does that have enough of an effect on the aggregate
statistics, if it was taken into account (e.g. count each crossing as 1.1
people, if 10% of beam crossings are 2 people)?

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simonebrunozzi
> We reasoned, if a solution didn't already exist — which surely it must — it
> shouldn't be more than a weekend project. How hard could it be to count
> people?

Not sure if this is really what happened (no reason not to trust them; but
sometimes founders' stories are rewritten), but it's just so cool to start
like that and become a large, well funded startup.

~~~
afar
This one's legit (cofounder here). We honestly thought it would be a side
project. We originally used a raspberry pi and two TP-Links to recreate a
router
([https://www.youtube.com/watch?v=yRGa9-QUDWo&t=7s](https://www.youtube.com/watch?v=yRGa9-QUDWo&t=7s)).
People are really hard to count.

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blklane
Great team with an excellent product that was able to re-position extremely
well during the current COVID era. Hats off to all at Density.

Worked with this team ~8 years ago when in college at my first startup and
they were a consultancy. Smart people who I learned lots from when starting
out and always enjoy hearing their continued success.

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shekispeaks
On my street in SF that has a dead end, cars keep coming up looking for
parking and on weekends they usually find nothing. But they get stuck turning
around and cause a mess.

Could I use Density to count cars and display number of empty spots at the
entrance of my street?

~~~
afar
Can't count cars at the moment, unfortunately. But there's some cool tech from
Flocksafety and other camera solutions.

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TLightful
Obviously impressive and good timing. Congratulations.

But, I'm afraid this is what popped into my head. It must be me:
[https://www.youtube.com/watch?v=PqKmb7SSpTE](https://www.youtube.com/watch?v=PqKmb7SSpTE)

~~~
afar
Gold. Proud to be affiliated.

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mobeigi
A pretty cool product and very useful! I hope something like this becomes
super wide spread (maybe with competitors as pricing is a bit wack) so we can
always know how busy our local stores etc are before heading out.

~~~
afar
If it becomes super wide spread, we'd make it low to no cost to provide wait
times to end users.

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friscofoodie
this is an awesome product. I could see tons of businesses using this to
reopen safely during the pandemic. +1 for making it anonymous anti-camera

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systemvoltage
Aside: Haven't seen "Made in USA" in a long time, refreshing to see that
Density hardware will be manufactured in Syracuse, NY:
[https://www.density.io/hardware/](https://www.density.io/hardware/)

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james412
Anyone know what kind of depth measurement they are making? It looks like some
kind of radio widget

~~~
guscost
Density (software) engineer here. Our sensor uses active infrared lasers to
read depth, and it classifies "persons" with a deep-learning algorithm that
runs on the device.

~~~
dexterdog
Why not just scan for MAC addresses? Legal reasons? Can't you black box
something like that and not safe the actual IDs but use them for unique
counting?

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PragmaticPulp
Most OSes and devices randomize MAC addresses during scans to prevent this:
[https://en.wikipedia.org/wiki/MAC_spoofing#MAC_Address_Rando...](https://en.wikipedia.org/wiki/MAC_spoofing#MAC_Address_Randomization_in_WiFi)

It's also not guaranteed that every person is carrying a phone or that their
phone is turned on.

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robk
there's a grocery store equivalent in the UK called Crowdless

~~~
JshWright
That seems like a decent solution if you don't care about any sort of
accuracy, and are ok with very rough estimates (which is certainly reasonable
for some use cases).

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alphagrep12345
Who would need exact accuracy? Why won't people be okay with numbers which are
a bit off, but much cheaper?

