Objectvideo V4 To Detect Fires?

A few years ago, we set a client up with a system consisting of four FLIR cameras and a Pelco Esprit PTZ atop a 50' tower in the middle of a two-square-block truck yard... the FLIR cameras then feed into a MangoDSP A/D box coupled to an ObjectVideo v4 analytics system. The relay outputs of the Mango feed six zone inputs on an alarm panel, so that trigger outputs from the OV system send a corresponding signal to a monitoring station.

This morning we got a call from the client wondering why their system - which had had preventative maintenance barely a month ago - failed to pick up and alert the monitoring station to a truck in the yard that had caught fire and burned(!!!) during the night. Apparently the fire department told them the truck had already been burning for upwards of three hours by the time they got there around 5am... well, the recorded video showed that workers had been in the yard as recently as 3:20am and have even been in the area of the burned truck, so obviously that wasn't right. Further checking of the video showed that the truck went up at around 4:12am - the heat bloom from the fire shows up great on the FLIR!

In looking at the analytics logs, I realized why the system hadn't alerted to the fire: it simply wasn't programmed to. The original purpose of it was to detect PEOPLE in the yard during off-hours, and alert the monitoring station (workers who are supposed to be there after hours call the station before entering to inform them, and the station always has the ability to pull up the remote feed to check on activity via the Esprit). In fact, it was performing exactly as it was supposed to: at about 4:36am, another truck pulls in, and barely a minute later, the system triggers as the driver leaves his cab to investigate the fire.

Anyway (and now we're getting to the question part), the client now wants the system re-programmed to sense larger heat events... like fires (this is the first one I've heard of in the 8+ years we've been working with these guys)... and I'm not quite sure how I'm going to define that for the analytics engine, which frankly, is a pain in the arse to program anyway. I figure I could tell it to watch for larger objects appearing in the yard... it will, of course, trigger on any trucks that come in, but if there's a truck, there's going to be a person appearing shortly that will trip it anyway, so that's not really a big deal. Main problem I see is that trucks usually appear as big square blocks, whereas this one fire was... well, pretty much the shape of a REALLY BIG candle flame when it went up. It could almost be seen as a large person-shaped object, and something tells me this is going to prove extra-challenging to define.

So, any thoughts on this, analytics experts, particularly anyone more familiar with older OV? Note that these FLIRs are B&W, and trucks and people pretty much just appear white to them, so there's not any granularity available to tell the system to detect "REALLY hot" vs. just body or engine temperature.