I love when people do stuff like this. Some guy takes a self portrait every day for 8 years.
If the internet can post stuff like this, who is to stop me from analyzing it? Really, this is what I love. Seeing something online and then seeing what extra information I can get from it. In this case, of course, it's hair.
Is It Really 8 Years?
Let me do a quick check. Looking at the video, there are 1,340 frames with changing faces. If the video covers 8 years, that would be 8 x 365 (plus two leap days) = 2,922 days. So, he is either missing some days or missing some frames in his video. Unfortunately, there is no indication of the actual date on images. Then why aren't there the correct number of frames? Here are some options.
- This guy is in the picture-a-day Union, which actually only requires 3 to 4 pictures a week.
- The guy actually did take one picture a day. However, in the video encoding process some of the frames were dropped.
- He just recored a picture every other day and assumed no one would notice.
- He did take a picture each day for a year. The problem is that he is not on Earth, but some asteroid orbiting the Sun in between Venus and Mercury with an orbital period of 167 days. This would give 1340 frames in 8 years. No one ever said it had to be 8 Earth-years.
OK. So, I am going to have to make an assumption in order to analyze this video. Let me just pretend that he took one picture every other day. The video isn't a complete waste, though. I really like that he used software that makes his eyes in the same location in each frame. This really helps with an analysis. Of course, there is still the problem of his head being tilted forward or back -- but I will just ignore that.
Looking at the Hair on Top
My first idea was to measure the height of the hair on the top of his head. Of course, I don't want to measure his hair style, just the hair. To account for this, I measured two things: the approximate position of his hair line and the approximate average height of his hair. Here is an example.
Yes, I know these positions are just approximations. Also, the top one isn't a direct measure of the length of his hair because his hair isn't standing straight up. Of course, these logical arguments won't stop me from getting some data anyway. Oh, I guess I should say something about scale. How can I determine the length of hair in real units -- like meters? I have to make another guess. Let me assume that the length of this guy's face is 25 centimeters. Again, just a guess.
Why couldn't I just measure the top of his head? If I did that, there would be some vertical motion just due to the position of his head. Imagine he is looking up. In this case, it would make it seem as though the top of his hair is higher -- but also his hairline would be higher. That way I can just look at the difference in top and hair line. Here is a plot of that data for about the first two years.
I agree with you. This data doesn't look all too useful. I think there are maybe a couple of parts that I could find the rate of hair growth, but there seems to be too much noise. I suspect the problem is that the "style" part of his hair along with the tilt of the head just makes too much error.
Sideburns
Actually, I am not too sure about this. I guess the hair on the side of his hair near his ears would be his sideburns. However, there are two ways hair can get longer here. It could be longer hair from higher above growing down (which is what I will assume). The other option is that the sideburns gets longer because new hair grows out that he doesn't shave. If I squint real hard and watch the video, it looks like it is the first option.
Also, with the sideburns, they are close to the eyes. This means that titling the head between frames won't change the position of the hair so much. Along with this, he rarely styles his sideburns. I think the change in vertical position of the bottom of the sideburn isn't a terrible representation of the hair. Here is a plot of his sideburns (from the right side of his face).
As you can see, I can fit a linear function to part of this data. The fit gives a slope of about 0.0003 meters/day. (I know it says units of seconds for the horizontal axis - but a second is a day here.) Fitting a linear function to the other straight parts gives a very similar slope. So, I guess for this guy hair grows around 0.03 centimeter a day. With this rate, if he didn't cut his hair for 8 years (almost 3,000 days) his hair would grow about 0.9 meters (assuming a linear growth rate). Honestly, I know very little about hair growth.
Hair Cuts
One more thing. How often does this guy get a haircut? Assuming 2 days per frame, he gets a haircut (all of them cut) on days: 61, 134, 188, 244, 316, 380. This gives a haircut about every 2 months (give or take). Again, this assumes each frame is about 2 days. Also, this seems like a reasonable time frame to get a haircut. Really, what would I know? I don't have much hair and just cut it myself.
