Questions tagged [camera]
A device used to record static or moving images, either digitally or on a physical medium. The images captured may be in any region of the electromagnetic spectrum such as x-ray, infrared, visible, or ultraviolet and beyond.
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How can I focus an optical device at infinity, inside a room with limited space?
I have a custom coupled camera/spectrograph imaging system that I need to focus at infinity for a microscope setup. I can't move the device outside, where I would be able to use some distant object to ...
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How does photons per second relate to lumen or lux?
So I am trying to calculate how many lumen or lux I need on the camera sensor in order for it to saturate.
I have:
Well depth: 12600 e-
Quantum efficiency: 40%
Exposure time: 4 ms
So my guess ...
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1answer
27 views
Optics of an all-sky camera
I'm curious about the optics of an all sky camera like this one or this one. My suspicion is that the sensor has an inherently wide field of view - the former has a lens that's 1.55, which doesn't ...
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0answers
15 views
Calculating required amount of lumen for camera sensor satuation
I am stuck on this problem at work - I hope some of you can help me further.
I work with underwater vision and am trying to find way or methodology to get a somewhat estimate of the required light ...
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0answers
19 views
How practical is a universal anti-fisheye lens (rectilinear)?
Is there a (practical) rectilinear lens that will "undo" a fisheye lens of webcam/phone size?
To explain "practical", consider that there are clip-on lenses for phone cameras: wide angle, macro, and ...
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1answer
42 views
Are These Guitar Strings Demonstrating Subharmonics?
This video has a fair few instances where there is an exaggerated wiggling of the guitar strings. I rationalise this by saying its a similar effect to rotoscoping, like where wheels appear to spin ...
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3answers
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Strange optical distortion in a video recorded from an airplane window
I recorded this video from an airplane window while it was decreasing its elevation. What is the explanation for this optical distortion? This distortion appeared only in a certain range of elevation. ...
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1answer
14 views
Photomulitplyer Tubes and NaI(TI) crystals in Gamma Camera, Energy and spatial resolution
I am trying to understand how the PM tubes and NaI(TI) crystals are used for the energy and spatial resolution.
I understand the principle behind how the crystals and PMT work, but very confused to ...
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1answer
18 views
Can a controlled lighting environment be a substitute for bandpass light filters?
Could illuminating a subject with different LEDs be used instead of bandpass filters?
I am experimenting with capturing surface reflectance using a monochrome camera. The traditional approach to ...
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0answers
44 views
Calculating light level radiating back to camera from rough surface
Problem statement: I have an imaging sensor (“camera”) that has a minimal response specified at 1000 lux. This camera is set up to resolve a rough surface at 1 meter distance. Alongside the camera is ...
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1answer
33 views
Solving for $x$ and $y$ image coordinate given a 3D point
I have a 3D point, $(X, Y ,Z)$ and I want to know where it's imaged, $(u, v)$. I'm assuming a pinhole camera model with no lens distortion. I have the distance from the pinhole to the object ($z$), as ...
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1answer
27 views
How do I calculate the geometric dimensions of the following objects, given the image co-ordinates, and camera information?
I've zero knowledge in optics, but I've to estimate the geometric dimensions of objects from the values of the number of pixels and the camera information given here: https://www.raspberrypi.org/...
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25 views
what needs to be minded when changing the lens on a Time of Flight camera
Okay, so first of all I'm not really an expert when it comes to optics,
but I have a small project where I would like to simulate how the behavior would change if I apply a different lens on the ToF-...
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2answers
40 views
Why doesn't projected image fill all my camera view?
so lets say i take a small lcd, and stick a lens in front of it. a magnified image will be projected on a wall. now lets remove this wall and stick a camera a little behind where the image is formed (...
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0answers
23 views
Why is the focal length of a camera inextricably linked to a different perspective?
The human eye can focus on different distances without ever changing the perspective. Why is the change of focal length in a camera, on the other hand, always linked to a change in perspective? Is the ...
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4answers
234 views
Focal Length Definition in a Camera
I am having trouble understanding the meaning of focal length. I thought focal length was the distance between the lens and image sensor. These sources validate that definition:
http://ksimek.github....
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0answers
13 views
Calculate bounds of image (sqft) given height of camera looking straight down
I'd like to calculate, with reasonable accuracy, the area of a camera image given the height of the camera, and the fact that it is looking straight down at the ground. I'm wondering what ...
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2answers
89 views
Why can my camera see the Sun when I can't?
There was a lot of smoke blowing high over the west coast of the United States last summer due to forest fires. It was thick enough that near the horizon, the Sun was all but invisible. It could ...
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1answer
52 views
2 lens microscope with an iphone camera. Where should the imaging plane be?
I am trying to design a 2 lens microscope that can be attached to an iphone camera in Zemax. To optimize the point spread function I need to define an imaging plane at which it should be optimized. ...
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1answer
31 views
Remove lens distorsion with intrinsic or extrinsic parameters?
I'm struggling with the theoretics of camera calibration. There are the intrinsic parameters and the ...
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1answer
63 views
What are the difficulties of constructing a camera with $3.10^{8}$FPS? [closed]
what are the difficulties of constructing a camera with $3.10^{8}$ frames per second (FPS)? In order to study the nature and speed of light, can we construct a camera with $3.10^{8}$ FPS?
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1answer
61 views
Cameras in Voyager probes 2017 [closed]
Riffing off an old thread...
Analog v digital and data transmission aside, I'm wondering how images were captured in such low light at 37,000+mph. Seems like a wide open aperture and slow shutter ...
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0answers
113 views
Viewing totality though an unfiltered telescope [closed]
DISCLAIMER: This question is for informational purposes only and the ensuing discussion must not be construed as safety advice.
There seems to be a consensus among experts that partial eclipse should ...
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0answers
63 views
Lens equivalent depth of field
In digital photography, there's the principle of lens equivalency, according to which, when you shoot with a camera which has a smaller sensor than a full frame sensor (which is the same dimension as ...
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3answers
1k views
Why can a regular infrared camera not show temperature (thermography)?
There are a lot of questions here dealing with infrared cameras and thermographic cameras. I think I understand the reason why a thermographic camera is able to retrieve the temperature values from ...
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1answer
96 views
Filter for RGB separation
Looking at Bayer filter of a typical consumer camera, one can easily see that sensitivity of the filter for each color is all over the place. Are there filters similar to Bayer that do a better job at ...
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1answer
118 views
Will the image of a pinhole camera be shifted if the light source is shifted as well?
If the angle of incidence ray is = to the angle of reflection. Then if the light source is shifted won't the image change too?
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1answer
66 views
Could aliens observe Curiosity, the rover?
Inspired by:
The color image, taken from a distance of 169 miles, is the combined view of three wavelength bands — red, blue-green and infrared.
Curiosity is not the only Earth visitor that ...
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0answers
304 views
Matching light flicker rate with camera's FPS
I know you can make water flow backward or make plants seem alive by changing the frame rate per second(FPS) of a camera. But what would happen if the camera took a video in an environment where the ...
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1answer
489 views
How to calculate the size of object in pixels, knowing the camera properties?
I'm trying to calculate the size of an object in pixels in an image, when I have these information:
...
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0answers
37 views
Meaning of signal-to-noise ratio for a CCD camera
What is the meaning of signal-to-noise ratio for a CCD camera and what information is inferred from that? Is noise playing the role of error in measurement? If so, then an S/N equal to 10, for example,...
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1answer
88 views
Nonlinear Response of CCD camera
What is meant when it is said a CCD's response is nonlinear? Does it mean the value of a pixel of the camera is not proportional to the number of received photons? Does it involve saturation? What ...
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2answers
350 views
Why a circular camera lens captures rectangular pictures
I want to know how a circular camera lens captures a rectangular picture.
Moreover what will happen if the lens was rectangular.
I have tried a lot to think about it but i could not figure out ...
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2answers
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Photographing the night sky - How important is fixed alignment of the camera?
If I set up my long exposure camera on a tripod and point it at the sky at night with the pole star in the centre we get a lovely image of concentric circles or arcs of circles depending on exposure ...
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5answers
16k views
Why doesn't Earth appear smudgy or blurred in space photographs due to its fast rotation?
Whenever we take a photograph of something moving at a considerably high speed, its image appears fuzzy/smudgy/distorted due to motion blur. Why doesn't this happen in case of Earth photographs from ...
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4answers
313 views
Does a camera have single slit interference?
Because a camera has an aperture, I would think that there is single slit interference?
Does a camera have mechanisms to account for that?
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1answer
4k views
What causes the Sun to appear to be in front of a building in this picture?
I took this photograph a few days ago, during sunrise, using my smartphone camera and digital zoom:
It seems that the sun is in front of the building. How is this explained?
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5answers
3k views
Is there any advantage in stacking multiple images vs a single long exposure?
Suppose I have a source object that is not time varying, to be concrete let's say it's a galaxy. Is there anything additional that can be learned or done with multiple short exposure images of exactly ...
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1answer
249 views
Does Bayer demosaicing from RGB-filter sensors work *because* the color filters are imprecise?
I have an ongoing friendly dispute with another member over on Photo Stack Exchange about the fundamentals of how RAW works, and I'm hoping you can settle it.
My understanding is that Bayer ...
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1answer
197 views
Why are filter flare images centrally inverted?
A previous question asked about the origin of the ghost-like image of the fluorescent bulb on this image,
which turns out to be something called a filter flare, of which there are more examples here ...
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2answers
3k views
What is this blue thing in a photograph of a bright light?
It looks like the bulb of the lamp beside it but how why what
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1answer
121 views
How dark is our universe(space) to us?
Yesterday I made a few photos from ISS
and then made this aweseome gif out of them.
If one would go out at night, where are no disturbances of city lights, one would see a bright, black, starry sky ...
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5answers
2k views
Technical explanation of “Hitachi lensless camera”
Hitachi is bragging about a thin lensless camera. I can't find any technical information on how it works---just press releases etc.† Can anyone work backwards from the published descriptions to ...
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1answer
1k views
Type of light that is not visible to human eye but only visible to cameras?
We are trying to project a grid on a surface and are trying to find the best type of light that would be invisible to the naked eye but could be captured by a camera.
The light should be uniquely ...
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1answer
248 views
SLR camera gyroscopic stabilization - limited by rotation of the earth?
In this photography stackexchange answer it is stated that the limits of performance of gyroscopic stabilization of an Olympus handheld camera is related to the rotation of the earth. I'm further ...
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2answers
107 views
Does a camera measure intensity? (picture of diffraction pattern on a wall)
I was performing a diffraction experiment with a slit of width 0.08mm (reported by the manufacturer). The conditions of my experiment allowed the Fraunhofer approximations. Thus, doing the Fourier ...
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0answers
66 views
Periscope camera with a mobile phone, how to make walls not visible on the camera/alternative solution? [closed]
I am trying to make like a "periscope" that i can use with a mobile camera. I have made a very quick prototype with two mirrors and it "works" but you can see the interior of the walls so it is not a ...
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2answers
118 views
Why does image noise happen?
Why are digital images shot with a high iso (which means the camera sensor is much more sensitive to light) so much grainer than pictures taken with a lower iso? Here is an example of the type of ...
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2answers
25k views
Green dot on photos when taking photo facing the sun
When taking a photo towards the sun, I found there is a green dot on the photo. I'm pretty sure this is caused by the sun, the camera has no problem. Question: what is the cause of this green dot? why ...
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2answers
2k views
How can IR cameras see things colder than the camera?
I’ve read that only cold-blooded animals develop IR vision to spot warm prey because a mammal would blind himself with his own heat and not be able to see anything.
But I’ve seen a FLIR camera, ...
