1,360
edits
ALS infrared vision: Difference between revisions
Jump to navigation
Jump to search
→IR emission physics
(Created page with "Modern aircraft may be equipped with [https://en.wikipedia.org/wiki/Forward_looking_infrared FLIR] devices that enable the pilot to see in infrared wavelength, i.e. directly p...") |
|||
| Line 14: | Line 14: | ||
The sun-driven temperature contrasts are also influenced by the weather. Clouds are fairly good absorbers of IR radiation and prevent both the heating of terrain during the day and the cooling during the night, i.e. contrast in IR images tends to be lower in poor weather. | The sun-driven temperature contrasts are also influenced by the weather. Clouds are fairly good absorbers of IR radiation and prevent both the heating of terrain during the day and the cooling during the night, i.e. contrast in IR images tends to be lower in poor weather. | ||
== ALS examples == | |||
The following examples show IR vision rendered with ALS. | |||
At a few hours after midnight, the water in the background appears fairly warm while the terrain in the foreground has cooled off. The runway (especially the white-colored markings) are among the coolest objects in the scene. Also the thin foliage of trees cools rapidly in the night air. | |||
[[File:IR vision01.jpg|600px|ALS IR vision example]] | |||
At high noon in clear weather, the situation has completely reversed and the runway and trees are now among the brightest object, heating rapidly in the tropical sun. Note that while the scene is brighter than at midnight, it's not by much - while average temperatures during the day are higher than at night, the IR emission spectrum is not nearly as much changed as the visible spectrum when the sun is below the horizon. | |||
[[File:IR vision02.jpg|600px|ALS IR vision example]] | |||
The same scene and same time (noon) under an overcast sky shows all contrasts muted by the strong absorption of IR radiation in the cloud layer. | |||
[[File:IR vision03.jpg|600px|ALS IR vision example]] | |||
The daily variation of soil and concrete temperature with respect to the hardly changing water leads to the appearance of times when they have about the same temperature. Then (usually in the early morning and after sundown in the evening) almost no contrast between terrain and water is apparent in the IR. | |||
[[File:IR vision04.jpg|600px|ALS IR vision example]] | |||
== Preparing models for IR vision == | |||