Angsizing a Pixel length in an image?

[CNBA3]

What I am trying to find is a method to find the size of a pixel length in the middle of an image when comparing the distance between another established point to panel length.

Example:

• Panel dimensions are (993 × 802 pixels)
• Pixel length 1 = 180px = 874.87m
• Distance 1 = (874.87 * 802) / [180 * 2tan(70/2 deg)] = 2783.9m
• Pixel length 2 = 900px (distance Pixel length one is 41 px)
• Distance Pixel = 130

Thoughts on how to find length of Pixel length 2?

 

[CNBA3]

I tried out a method such as ratio difference from (130:41) pixels to (2783.9:878) meters. and then done a calc with the distance from the explosion to the panel (2 atan (tan (70deg/2) * (900/802)) = 1.3320062 rad = 76.32 degrees)

and then using https://www.1728.org/angsize.htm

I would find the size from the distance and degrees which is 2973.7 meters.

Is this fine?

 

[CNBA3]

Bump

 

[CNBA3]

Bump

 

[KLOL506]

Well, if you know the distance between PoV and the faraway object whose pixel length you are trying to measure, this is the shortcut formula without having to fiddle around with the angsize calculator.

Object size = 2*tan(70deg/2) * distance from point of view to object * object height in pixels / panel height in pixels

 

[CNBA3]

Well, if you know the distance between PoV and the faraway object whose pixel length you are trying to measure, this is the shortcut formula without having to fiddle around with the angsize calculator.

Object size = 2*tan(70deg/2) * distance from point of view to object * object height in pixels / panel height in pixels

What I am looking for is from the image link in the OP is the Object size of the explosion diameter (900px) in the middle of the distance (2783.9m) from POV to the faraway Object (180px = 874.87m).

 

[CNBA3]

Bump