
How A.I. Helped Improve Crowd Counting in Hong Kong Protests - pseudolus
https://www.nytimes.com/interactive/2019/07/03/world/asia/hong-kong-protest-crowd-ai.html
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jimfleming
The article's demonstration of a counting model is horribly inaccurate to the
point where I'm not sure why it was included. Most people see "AI" as being
either good at something or not. There's little nuance such as some models
being better than others. This kind of demonstration just weakens the reader's
confidence in more fully developed results or different approaches. I'm not
sure this brief statement offsets the prominent visuals:

> On the day of the protest, Mr. Yip and the A.I. team used technology that is
> much more advanced. They spent weeks training their program to improve its
> accuracy in analyzing crowd imagery.

Setting aside the presentation, from the photos the researchers appear to be
using object detection rather than density estimation. This choice is
problematic given the quantities involved and the need for temporal
consistency.

I'm also skeptical of using human volunteers and surveys to calibrate the
model. Humans are terrible at counting large numbers of people in real-time.
That's a central point of the article with different groups of people
providing wildly different counts.

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fspeech
You can count from a still picture or a video segment and use that to test or
calibrate. So it may just be inaccurate reporting to give the impression that
the calibration depends on humans surveying live action, which is exactly what
they are working to replace. If the researchers publish their results the
exact methodology used will tell but I assume they are competent.

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ngcc_hk
Why do not need to count in the first place? whilst scale of protests
important, who has counted the crowd. And given the authority ignored it why
bother? The counting is silly the walk is not.

Anyway walk the three walk and given I do not pass the bridge, my legs hut
until 3 days later. I have not been counted but I know I have walked.

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mr_gibbins
Oh for __* 's sake. Companies and institutions are desperate to justify their
AI investment any way they can.

They would have gotten a perfectly good estimate by taking some photos of the
crowd at different density areas over the day and doing some good old-
fashioned sampling and extrapolation. Something that could be done by primary
school students (and is done, remember counting cars or sampling insects on
field days?).

Just because you can, doesn't mean you should.

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noeltock
Seems the NYT labelling for the bottom chart is broken/offset.

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m3kw9
The problem is they cannot back test the final result.

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calyth2018
Or back test the previous protests that has always been highly divergent
results.

Even if you take this AI approach at face value, it is evident that the
police's count is not _that_ far off, compared to the organizer's estimates.

But hey, the po-po is always bad, no?

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vnchr
Po-po _definitely not_ always bad, but there is damning evidence of their
false-flag interference in this particular protest.

