I am coming to grips with the fact that I am a barcode nerd. The strongest evidence of this is that I get a little excited when I see barcode technology being used in a movie or TV show that I’m watching. I perk up and watch a little closer to see what hardware is being used and make sure it’s portrayed accurately. If it’s not, I know we’ll get calls from people wanting to do something just like that. Then we have the unhappy task of bursting their bubble.
I’m also a bit of a CSI nerd. It is one of my all-time favorite TV shows. I love trying to figure out a mystery and I love the science they use to do it. I don’t know anything about forensics, but I do know they have forensics experts on staff and it
seems to be portrayed fairly accurately.
Over the years, barcodes have come into play in an investigation. Most of the time, they portray barcoding correctly and few things make me happier. Other TV shows have really mishandled barcode technology and have even completely fabricated some things. But on CSI, I can think of only one time where they stretched the truth a little.
That is, until last week in the
"Hitting for the Cycle" episode. Oh, how it broke my heart! Let’s dissect the scene and I’ll point out the COD (cause of death), much like Doc Robbins did for the numerous victims on that episode.
The Set Up
In the case of a dead gamer, CSI Sarah Sidle found a prescription bottle at the crime scene but couldn’t collect it because it wasn’t prescribed to the victim and therefore wasn’t a tie to the death at the time. Later, they thought that perhaps the victim had been drugged by the medicine in the bottle.
The Barcode
Sarah had taken a photograph of the bottle, which she pulled up on her computer screen. The portion of the label with the patient’s name had been damaged, so they couldn’t read it (how then did she know when she first saw it that it wasn’t prescribed to the victim? hmm…). However, the barcode was intact.
Sarah whips out her iPhone and scans the barcode off her computer screen. Some barcode scanners can read barcodes off of computer or cell phone screens. There are also lots of different barcode scanning apps. Since those apps use the camera to capture the barcode, I don’t foresee them having an issue with reading a barcode off a computer screen.
Blunt Force Trauma with a Curved Surface
The problem with trying to capture this particular barcode is that it was curved
around the bottle. Even if they had the bottle in their hands, it’d be extremely difficult, if not impossible to read that barcode.
Barcode scanners’ scan lines don’t bend around curved surfaces. As the barcode wraps around the bottle, the black lines and white spaces become distorted to the eye of the barcode reader. The only hope to read a barcode like this would be with a pen-style scanner that is manually swiped across the barcode. Even so, that must be done at a particular angle and rate of speed, which is hard enough to do on a flat surface, let alone a curved bottle.
The pharmacy that printed that barcode label really needs to call our barcode experts and get some help with their label design! Oh, wait, they’re fictional. I meant to say CBS’s prop department.
Symbology Poisoning
The real killer was revealed when Sarah’s iPhone pulled up the barcode data.
The barcode on the label is a linear barcode, probably a Code 128. Linear barcodes encode one string of characters. You can see that the human readable characters for that barcode are printed at the bottom of the code. It’s a string of alphanumeric characters. I see about 15 on the front of the bottle, but there are some more wrapping around the right side.
Linear barcodes are used to reference an entry in a database. It’s like a license plate number. By itself it’s meaningless, but you can use it to access all kinds of information from the DMV’s database. Without its database, a linear barcode is useless.
Yet, Sarah’s iPhone immediately popped up a window with the patient’s name, drug name, dosage, etc., etc. That much information could only be encoded in a 2D barcode like a Data Matrix. Actually, if that pharmacy, I mean, CBS’s prop dept. had used a 2D barcode, it would take up much less space on the label and it wouldn’t wrap around the curved surface.
There was one rather far-fetched explanation for how Sarah got that much information from one linear barcode. Perhaps she has another app on her iPhone that instantly accesses every pharmacy’s database in Las Vegas. Or maybe all of the pharmacies in Vegas use a centralized database. But still, wouldn’t she need a warrant to access that? I can see HIPAA having a conniption fit over that!
It is Just a TV Show
I know, I know…I wouldn’t mind so much if it were a comedy. The audience knows not to take things too seriously on sit-coms. But CSI is a serious crime drama that focuses heavily on science. They’re better than this! Maybe they should bring in a barcode expert to consult on episodes like this. CBS? Are you listening?
