Une vidéo d'Alison Kruse...

"It occurs when sources of light exceed the full well capacity (the electron-holding capacity) of the pixels on which they are being recorded. As a light-gathering pixel exceeds its capacity to hold captured photons, the excess energy spills over into the adjacent pixel (or pixels, if the second pixel also fills to its capacity). This spillover, called “blooming,” produces a spike of light.”

Gilles Fernandez said...
"... I remember too IR cameras are affected by humidity (when 60% or above) and its creates "artefacts". The beam is correlated with the pulse ... of the craft..."

Exactly. The humidity refers to the state of the atmosphere surrounding the source--in this case, the airplane/UFO/whatever-it-is.

The source is obviously pulsing, IN ADDITION TO, the laser pulses. My conjecture is that there is an FAA-standard anti-collision strobe on the bottom of the source. What's happening is that the light from the strobe is scattering off the humidity (and possibly suspended water droplets) in a spherical volume of air surrounding the source, creating a penumbra. At the instant the strobe reaches its peak intensity, the apparent size of the pulse is basically the size of the penumbra.

Further: "I imagine that if the pulses are coming from military aircraft, such events are rare..."

Well, not necessarily. Traditionally, altimetry and terrain countour mapping from aircraft platforms has been done with radar and microwave frequencies, which would not create a visible signature. Within the last decade or so, there has been a gradual encroachment of lasers into the applications traditionally occupied by RF devices. So, I would expect to see more and more of this kind of signature, as time goes by.

One thing to consider, however, is how much power is actually being radiated by the laser. I would have to think that there are regulations imposed by some government organization or other that limit the power of lasers that can be beamed from the air to the ground, over civilian airspace. It would certainly have to be a low enough limit so as not to cause blindness, if someone on the ground happened to be looking up at it.

If it were possible to estimate the distance from the camera to the UFO, it might be possible to estimate the power level of the laser beam. If it came out in the milliwatt range, that would be entirely consistent with a laser altimeter. If it came out in the kilowatt range, then that would be an entirely different kettle of fish...

Gilles F. a écrit:Merci pour le feed-back, Sébastien.
J'ai essayé brièvement (weekend) de trouver des artefacts listés de cameras IR.
Car cela me rappelle un effet "pixel blooming ou bleeding" des capteurs :

"It occurs when sources of light exceed the full well capacity (the electron-holding capacity) of the pixels on which they are being recorded. As a light-gathering pixel exceeds its capacity to hold captured photons, the excess energy spills over into the adjacent pixel (or pixels, if the second pixel also fills to its capacity). This spillover, called “blooming,” produces a spike of light.”

C'est effectivement un effet de saturation du même genre que le "blooming effect".
J'ai d'autres exemples similaires produits également avec des caméras IR. Si je me souviens bien ce que j'avais dit à l'époque sur ATS, il existe une relation directe entre l'intensité lumineuse produite par l'objet et la création de ce rayon lumineux; l'effet est purement, comme le dit Seb, numérique.
Je posterais un de ces exemples parlants à mon retour chez moi mercredi.

Gilles F. a écrit:
Bonsoir ElevenAugust,
Tu as retrouvé un ou plusieurs exemples similaires de tel effet sur camera IR depuis ta "database" stp ?
Gilles