How to get the length and width of a frame of the video generated by the drone in meters?

Joined
Jan 20, 2022
Messages
2
Reaction score
2
Age
34
I have the flight log of the drone where I can get the height at the instant of time I want. Also, I have the length and width information in pixels of the frame. How can I calculate the length and width in meters?
 
  • Like
Reactions: SkyFly

dirkclod

Moderator
Staff Member
Premium Pilot
Joined
May 9, 2014
Messages
15,628
Reaction score
9,572
Age
67
Location
Amory Mississippi
No idea but someone can tell you I’m sure.
Welcome to the forum and is nice if you post in intros first
so we know a little about you before you jump in asking questions. 👍
 
Joined
Jan 20, 2022
Messages
2
Reaction score
2
Age
34
Sorry, but your question doesn't make sense to me. Can you elaborate?
Let's assume that an area covered by the drone was filmed at an A x B resolution (in pixels). From the flight log generated, I have the height at each instant of time of this recording. So I would like to know how to find the dimensions of a video frame in meters. I tried to make a drawing to try to help in understanding.
1642753144656.png
 
  • Like
Reactions: SkyFly

Meta4

Premium Pilot
Joined
Jan 8, 2014
Messages
15,038
Reaction score
9,021
Let's assume that an area covered by the drone was filmed at an A x B resolution (in pixels). From the flight log generated, I have the height at each instant of time of this recording. So I would like to know how to find the dimensions of a video frame in meters. I tried to make a drawing to try to help in understanding.
The answer to your question will only be dependent on the height of the camera above the ground and the aspect ratio of the image.
You will need to use a Field of View calculator like this one:
 
Joined
Aug 7, 2016
Messages
1,401
Reaction score
862
Or simply calculate by the principles of geometry.

You have the width and length on the screen and you also have the distance from the ground, you calculate the size of the picture in the ground with the basic trigonometric function of the triangle.
 
  • Like
Reactions: snowghost
Joined
Aug 17, 2014
Messages
1,507
Reaction score
749
Location
Long Island, NY
A bit easier (at least for people like me who are math challenged) would be to locate the 4 corners of your frame in Google Earth and add a location pin at each corner. Then simply use the measure tool to find the length and width of the captured ground in feet. This is assuming you shot your video straight down, An oblique view would produce different ground distances across the top and bottom of the frame.
 
Joined
Sep 13, 2021
Messages
2
Reaction score
1
Age
57
Also need to factor in that drone is measuring height above takeoff point. If ground is sloping or up a hill or over a valley have more maths to do.
 
Joined
Mar 7, 2021
Messages
89
Reaction score
8
Age
62
There just do not exist sufficient data to calculate from pixel density and video dimension. One should use a 2D mapping software and use the phot geometry functions to calculate the dimensions.
 

Meta4

Premium Pilot
Joined
Jan 8, 2014
Messages
15,038
Reaction score
9,021
There just do not exist sufficient data to calculate from pixel density and video dimension. One should use a 2D mapping software and use the phot geometry functions to calculate the dimensions.
But it's a simple matter to find the field of view of the camera at any height.
 
Joined
Jan 23, 2016
Messages
300
Reaction score
88
Age
62
According to the P4P specs the horizontal Field Of View (FOV) is 84°.
Formula1: L = 2 x (h x tg(a/2))
Formula2: W = L / 16 x 9 (16:9 aspect ratio)
L=lenght, h=height, a=angle, W=width
tg(84/2)=0.9004
So at a height of 10 meters: L=18m & W=10.125m
CONDITIONS:
1. You're shooting (straight down) perpendicular to the ground.
2. The ground area is flat.
3. Height is from ground level, NOT take-off point.
Excel sheet:
 

Meta4

Premium Pilot
Joined
Jan 8, 2014
Messages
15,038
Reaction score
9,021
According to the P4P specs the horizontal Field Of View (FOV) is 84°.
The angle of view for camera lenses is usually given as a diagonal, not horizontal angle.
The FoV for the P4 pro is 84° diagonally.

Another factor to be considered in answering the OP's question is we don't know what video resolution/aspect ratio he is using ... 4096×2160, 3840×2160 or 2720×1530.
 
  • Like
Reactions: DoomMeister
Joined
Sep 21, 2015
Messages
67
Reaction score
27
Age
52
  • Like
Reactions: DoomMeister

New Threads

Members online

Forum statistics

Threads
141,855
Messages
1,458,733
Members
103,641
Latest member
marketingbaba78