Forensic Experts Say Screams Were Not Zimmerman's 1046
Hugh Pickens writes "As the Trayvon Martin controversy splinters into a debate about self-defense, a central question remains: Who was heard crying for help on a 911 call in the moments before the teen was shot? Now the Orlando Sentinel reports that Tom Owen, a leading expert in the field of forensic voice identification sought to answer that question by analyzing the recordings. His result: It was not George Zimmerman who called for help. Owen, forensic consultant for Owen Forensic Services LLC and chair emeritus for the American Board of Recorded Evidence, used voice identification software to rule out Zimmerman. Another expert contacted by the Sentinel, utilizing different techniques, came to the same conclusion. Owen used software called Easy Voice Biometrics to compare Zimmerman's voice to the 911 call screams. 'I took all of the screams and put those together, and cut out everything else,' says Owen. The software compared that audio to Zimmerman's voice and returned a 48 percent match. Owen says to reach a positive match with audio of this quality, he'd expect higher than 90 percent. Owen cannot confirm the voice as Trayvon's, because he didn't have a sample of the teen's voice to compare however 'you can say with reasonable scientific certainty that it's not Zimmerman.'"
Science or Pseudo-science? (Score:5, Interesting)
Another interesting discovery what was made... (Score:3, Interesting)
Was they located the ever elusive "white Hispanic." Not only are they using reputable software such as "Easy Bake Oven Biometrics" to prove that he did it, they were also able to make him of an entirely new race! Lets make sure we turn this into a race war as soon as possible!
Re:Does This Tool Actually Work? (Score:5, Interesting)
I think there's a significant problem in the way this software is being used in this case. It is one thing to say that, based on samples of an individual's voice, that there is X probability that some other voice sample could be from the same person. However, there isn't any way the software can do the opposite and prove a negative. For example, you can take hours of recordings of my voice from phone conversations and train the software. Now, if I make my voice sound like Donald Duck, or if I sing in falsetto, which are two types of sounds that would not be in the sampling of my normal voice, what probability would the software return that the silly voice matches my normal voice? It would be very low, at is should be.
In this case we have a sample of someone's NOT NORMAL VOICE. They are screaming and yelling. What voice samples of Zimmerman's were used to train the software? Was it recordings of him screaming and yelling? If not then of course the software will return a low probability. Actually, I'm surprised it returned as high of a probability as it did.
Now, as a side note, I think the news is really trying to inflame this whole deal. I think Zimmerman is likely in the wrong here, however, the media is running rampant with speculation. A good example are the video clips of Zimmerman at the police station, and them (news media) saying it doesn't look like his nose is broken, or that there doesn't appear to be blood all over him. That sort of thing is completely impossible to determine from the crappy, low resolution security video. Again, yes, if there was that much blood and it could be seen in the video, then a positive could be "proven", but just because it doesn't show up in the video doesn't mean he has significant injuries or a broken nose, etc.
Re:Hmm, cell phone audio at 8kbps? (Score:4, Interesting)
Cell phone audio is generally higher than 8kbps, even on GSM [wikipedia.org] where 12k-13kbps is typical. CDMA (including 3G networks) is as high or higher. That's plenty for very reliable voiceprint analysis. And in this case, they have all the samples of Zimmerman talking before the screaming encoded using the same method, making the comparison even easier.
Re:Does This Tool Actually Work? (Score:5, Interesting)
This reminds me of the infamous plane identification software. Its accuracy got up to 100%. They were so happy that they managed to do it. Put it out in the field and there were all sorts of false positives and false negatives. Turns out that the software got so good at guessing because with the test photos, all the good planes were shot against bright blue sky and the bad planes were shot against dark sky. The software made all its predictions based on the sky color.
Re:Does This Tool Actually Work? (Score:5, Interesting)
Voice analysis is a well established and studied technique. Unless you're particularly practiced and adept at disguising your voice, there are certain characteristics introduced by the physics of your vocal cords, throat, mouth, and nasal passages that are pretty consistent and identifiable, even with most people doing "impersonations" that sound like some other person. So, yes, it's reasonable to rule out that it was Zimmerman, in fact, it's more reliable at excluding people than at matching them. As Mr Owen points out, this recording has low background noise levels, and it's got a notable amount of Zimmerman's speech recorded in addition to the screams for help, so there is no issue introduced by aging, colds, etc. It's a nearly ideal case for matching.
Re:So what? (Score:4, Interesting)
It's because Zimmerman's father is a former judge.
That's a fact.
Re:In case you missed it (Score:5, Interesting)
Having seen the full video, I can come to only one conclusion: the video does not show any solid evidence of injuries because the quality is low. I saw some things that may have been injuries, but they could have just as easily been due to the shape of his head.
By the way, Sanford has put up the videos and 911 calls at http://sanfordfl.gov/investigation/trayvon_martin.html [sanfordfl.gov]
Re:Hmm, cell phone audio at 8kbps? (Score:4, Interesting)
Absolutely agree. I've actually written audio segmentation code for an alarm system that first obtained audio, not straight from an ADC, but only after the audio had been compressed. Compression absolutely destroys important details.
I'm also skeptical of the software's ability to take calm, slow speech, and from that determine what a scream OUGHT to sound like. Comparing samples generated by a person speaking under similar conditions and looking for similarities isn't that hard. But the science of of voice analysis isn't yet to the point where we can take a sample of audio and from that build a virtual larynx, throat, mouth, and controlling nerve fibers so that we can extrapolate from that what a scream from that might sound like.
This test might have been legitimate had the software been used to compare the scream on the 911 recording with another scream from Zimmerman, but that's not what was done.
Is this Richard Jewel again? (Score:5, Interesting)
After the Richard Jewel case I don't get into rush to judgement any more.
However the initial response of the police to let Zimmerman walk without a real investigation deserves a whole lot of criticism. Now we are getting the investigation so hopefully the facts will become evident.
Re:In case you missed it (Score:5, Interesting)
Bullshit (Score:0, Interesting)
Call me a racist if you like, but I have heard a lot of african-american voices, and the voice calling for help on that tape is not that of an african-american teenager. Either this kid sounded incredibly white, or the voice is not his.
Note that Trayvon's dad was played the tape and asked if the voice was his son's, and he confirmed that it was not Trayvon's voice calling for help. And also note that his dad has a typical african-american accent when you hear him talking in the videos.
So all this guy proved is that his voice matching software is shit.
Re:In case you missed it (Score:5, Interesting)
Interesting thing about the video is that the original source looks like it was recorded on videotape as interlaced NTSC! You can see this when there's a great deal of movement going on. Just look for areas of great contrast like the hood of the police car when it rolls in and you'll notice the odd saw-tooth appearance of the hood's edge. This happens in other places.
What this means is that a lot of what is being seen is what has been filled in by software as it deals with crappy NTSC. Noise, color fringing effects, are all smoothed out. Then lossy compression is used during the conversion to digital video and potentiall important detail is lost.
The result is that the video appears better than it really is.
This is what most people want when they're transferring analog video to digital. But here is it's absolutely essential that we see the raw, unaltered video, if for no other reason than for understanding the limits of equipment used. It possible the equipment just wasn't good enough to pick up the details we're looking for.
Re:So what? (Score:5, Interesting)
The weird thing I don't get about the "stand your ground" law in this case is how it can apply to both people. By his own account, Zimmerman was chasing Martin. Zimmerman was armed with a gun and was not in a marked security vehicle or wearing any sort of uniform, nor did he identify himself in any way as being part of the neighborhood watch. If Zimmerman had never shot Martin, but Martin had been arrested for attacking Zimmerman (and I'm not saying that's what happened, I'm just looking at Zimmerman's claimed version of events), then "stand your ground" should have been a viable defense for him. He was the one in fear for his life being chased by a suspicious stranger armed with a gun.
Everything that's been revealed about Zimmerman seems to show that he's basically a hyper-aggressive Gladys Kravitz with a gun. In the past he'd called 911 to report suspicious 7-9 year old black males, kids playing in the street, and, apparently, his landlord demanding the rent money. He forced this situation and someone else ended up dead. He's clearly at least guilty of manslaughter.
Re:So what? (Score:4, Interesting)
Actually, apparently Zimmerman's arrest in 2005 was specifically for resisting arrest (and assaulting a police officer, but that probably came after the police officer started arresting him for resisting arrest). That was during a domestic crisis situation.
Re:Does This Tool Actually Work? (Score:5, Interesting)
I'm undecided on wether Zimmerman is guilty or not without seeing further evidence myself. But it would be a stretch to call Trayvon "muscular". Kid weighed 140 pounds at 6' 3". I weigh that at 5' 7" and people think I'm too thin. He was a beanpole.
This is how it works. (Score:5, Interesting)
It's always bothered me that forensic science doesn't involve science. It would be easy enough to reproduce the events using the same phone and recording equipment and voice samples with a few different people to establish a baseline for what we "should" expect. But instead they simply can't be bothered with scientific controls. We are just supposed to take their word for it that it should be a "90%" match. I'm this context we don't even know what 90% means.
Re:What difference does it make? (Score:3, Interesting)
He followed and confronted someone for no good reason
No question that he followed Martin for a time. But "confronted"? I haven't seen anything to indicate that.
What little evidence there is seems to indicate the contrary; the 911 call appears to show Zimmerman got out of his car and followed Martin on foot. At some point he returned to his car where the shooting took place. It's not clear to me how Martin ended up there after Zimmerman left his car and walked some distance while talking to the 911 operator.
Re:So what? (Score:2, Interesting)
Someone is trying to start a race war in this country and I'd sure like to know why.
Because the whites declared equality was achieved, and the minorities know that to be a lie. The whites are causing the race war by defending the racists like Zimmerman who killed the boy because he was Black. If Martin hadn't been black, he wouldn't have been followed and attacked by Zimmerman and would still be alive, so Black is what killed him, and the system seems to be defending Zimmerman for killing some Black person.
Re:So what? (Score:2, Interesting)
http://www.youtube.com/watch?v=HqKSMMEYHxA [youtube.com]
I don't see any head injuries. Or any blood, which is funny, considering head wounds bleed a lot. Oh, and the fact he supposedly just shot a guy to death as the guy was on top of him. If his story is true, he should be covered in blood.
Whar blood, whar?
Re:So what? (Score:5, Interesting)
If "Stand your ground" means, that you can use deadly force against someone you feel threatened by if you are on your own hometurf, and Mr. Zimmerman can rightfully claim this, then how comes, Mr. Martin should not have the right to confront someone he feels threatened by with deadly force?
If Mr. Zimmerman had this right, then Mr. Martin had it more, because his fears were obviously justified.
Re:So what? (Score:3, Interesting)
I'm not so sure that "stalking" in this case was illegal per se, which would be necessary for Trayvon to be able to legally act in self-defense.
I believe it fits Florida's definition of harassment. Stalking is generally legally reserved for violating a restraining order, so I agree that I may have been using a common word correctly, but not the accurate legal term. Zimmerman was, from his account, illegally harassing a black youth because the youth "looked suspicious" (DWB on feet). I can't figure out the facts of this. There were apparently multiple 911 phone calls from multiple people, and not much of a timeline set up with who said what when. Zimmerman apparently called 911 to report the youth for being suspiciously Black, and the 911 operator told him to back off and let the police respond. Zimmerman knew he could handle anything because he had a gun and apparently wanted to use it. So Zimmerman continued to approach (follow, stalk, harass) the youth until the youth told him to go away, after which Zimmerman shot and killed him.
Robbers in someone else's house do not get to claim stand your ground defenses when they kill homeowners. Zimmerman killed the youth for being Black in *his* neighborhood. The response from the mostly white judicial system seems to indicate that such actions are ok, after all, aren't we all scared of those big bad Black people? I've seen people question the race issue, but none have said that they believe Zimmerman would have followed whites as religiously (and there have been bits of his history from his recorded 911 calls that indicate he only calls on Blacks, which is unusual, as they are a minority in that neighborhood).
Re:So what? (Score:5, Interesting)
In 2009 there were 2,867 black males killed in the United States, of which 2,604 were killed by other blacks, 209 killed by whites. Why the outrage in this case? Might it be various people made assumptions about how this would play out?
It might, might, might just have something to do with the fact that this was not such a cut and dry scenario, and the suspect wasn't arrested. Of those 2,867 killings you cite, how many of those killers were arrested for murder or manslaughter? How many of those cases were regarded as self-defense?
People are understandably quick to bring race into the equation, but on it's most underlying level, an unarmed boy was shot by a large adult with a gun and an arrest wasn't made. The unarmed boy was reportedly making a run for junk food for his younger brother, the armed man was at some point following the boy around after being advised not to because the police were on the way. It's suspicious, regardless of what color either character is.
Re:So what? (Score:2, Interesting)
Oh, I don't know... perhaps because a 17 year old kid who had been tracked down and attacked was fighting for his life? The human body is pretty powerful (ie, able to overcome the large size difference between the man and the teenager) when he chased down and assaulted the kid.
Of course, when Zimmerman shot him it was all over. Only so much the body can do. I mean, he had Skittles and Ice Tea on him - maybe if he ate those it would have cured the gunshot wound? Maybe he could have used those "in a threatening manner" against a much larger, angry, racist with a handgun.
Feared for his life? Please. He executed a black kid because he was committing the heinous crime of walking down the street while black.