Hello,
I would like to know what is the optimal or design angular velocity (rad/sec) when taking panorama pictures. Also, I would like to know what is the design radius corresponding to that angular velocity.
Thanks.
Probably you can do computation yourself.
The parameters are :
- number of images (frames) per second : nbFps (typically 24 ?)
- angular field of view : angFOV (typically 63° for iPhone 6 or 1.1 radian) see h ttps://www.wired.com/2015/05/measuring-field-view-iphone-6-camera/
Let's call angFOVrd = 1.1 rd and angFOVdeg = 63 deg
- pixelMovePerFrame: One could estimate (I'm not a photo specialist, so it is just a guess: this is a very critical parameter ; maybe you will find it is fine with up to 5 pixels per frame ?) that a max angular speed is pixelMovePerFrame pixel per frame, which means :
As FOV is about 500 pixels (resolution), that mean that pixelMovePerFrame pixel is
pixelMovePerFrame * 1.1 / 500 in radians = pixelMovePerFrame * angFOVrd / resolution
So, in a time of 1 / nbFPS, you should move by pixelMovePerFrame * aFOVrd / resolution
So max angular speed should be pixelMovePerFrame *angFOVrd * nbFPS / resolution rd/s or pixelMovePerFrame * angFOVdeg * nbFPS / resolution
If my figures are correct, that leads to :
For pixelMovePerFrame of 1 pixel:
1.1. * 24 / 500 = 0.05 rd/s
or
63 * 24 / 500 = 3 deg/sec, which means a complete 360° panorama in 2 minutes.
For pixelMovePerFrame of 5 pixel5:
5 * 1.1. * 24 / 500 = 0.25 rd/s
or
5 * 63 * 24 / 500 = 15 deg/sec, which means a complete 360° panorama in 24 seconds.
I let you check the exact values and adapt. And more important, test to estimate what is visually the correct value for pixelMovePerFrame.
Enjoy and good luck.
Could you give some precision ?
optimal or design angular velocity
optimal to what respect ? Compromise of image quality vs file size ?
What do you mean by "design radius"
Do you refer to any specific object property ? which ?
Otherwise, what do you mean exactly ?
Hello again,
Here is what I am looking for: While taking a panorama picture, the iOS will give you warnings if you are rotating the phone "too slow" or "too fast". Therefore, there is got to be a known optimal or design angular velocity to which the rotation of the panorama pictures was designed for. Optimal with respect to the image quality that would create a less "deflected" or "distorted" image.
Design radius is the distance from the iPhone to the center of that person holding the iPhone while taking the panorama picture. This will be normally end up being the person's arm length.
Please let me know if this answer your questions. I will be more than happy to clarify even further.
Thanks.
when you say "distance from the iPhone to the center of that person holding the iPhone" you seem to be implying that the rotation should happen around the center of the person. but the ideal rotation is around the center of the lens.
Actually, it should be the 'nodal point' of the lens but in such a small lens it won't matter.
Probably you can do computation yourself.
The parameters are :
- number of images (frames) per second : nbFps (typically 24 ?)
- angular field of view : angFOV (typically 63° for iPhone 6 or 1.1 radian) see h ttps://www.wired.com/2015/05/measuring-field-view-iphone-6-camera/
Let's call angFOVrd = 1.1 rd and angFOVdeg = 63 deg
- pixelMovePerFrame: One could estimate (I'm not a photo specialist, so it is just a guess: this is a very critical parameter ; maybe you will find it is fine with up to 5 pixels per frame ?) that a max angular speed is pixelMovePerFrame pixel per frame, which means :
As FOV is about 500 pixels (resolution), that mean that pixelMovePerFrame pixel is
pixelMovePerFrame * 1.1 / 500 in radians = pixelMovePerFrame * angFOVrd / resolution
So, in a time of 1 / nbFPS, you should move by pixelMovePerFrame * aFOVrd / resolution
So max angular speed should be pixelMovePerFrame *angFOVrd * nbFPS / resolution rd/s or pixelMovePerFrame * angFOVdeg * nbFPS / resolution
If my figures are correct, that leads to :
For pixelMovePerFrame of 1 pixel:
1.1. * 24 / 500 = 0.05 rd/s
or
63 * 24 / 500 = 3 deg/sec, which means a complete 360° panorama in 2 minutes.
For pixelMovePerFrame of 5 pixel5:
5 * 1.1. * 24 / 500 = 0.25 rd/s
or
5 * 63 * 24 / 500 = 15 deg/sec, which means a complete 360° panorama in 24 seconds.
I let you check the exact values and adapt. And more important, test to estimate what is visually the correct value for pixelMovePerFrame.
Enjoy and good luck.
