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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163 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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34 views

Calculate dark noise in CCD given a pixel's counts for two exposures

Suppose I took two pictures with the same CCD camera in totally dark room. The first picture was exposed for 1 microsecond, and the pixel given was 20 scales of grey. The second picture was exposed ...
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How I can add lenses stacked on front of iphone camera to increase magnifying power?

How we can stack different lenses to increase magnifiying power of a smartphone camera? Is there any way to test if stacked lenses will focus light on image sensor of smartphone exactly right before ...
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CalTech has actually filmed light crossing a space of 1 mm of space. How?

In the video https://www.youtube.com/watch?v=7Ys_yKGNFRQ, CalTech has a camera capable of filming the picoseconds it takes for light to travel 1mm in distance. It can do 10 Trillion frames per second....
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A Cheap Way for Seeing 1000nm to 1600nm Light

I have started a project in infrared where the spectrum covers 1000nm to 1600nm. A silicon based image sensors can see up to about 1000nm, while an iPhone attached FLIR camera can see from 8 – 14 µm, ...
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How can I determine the optics needed for a desk microscope?

As an noob to microscopy, photography, and optics in general, I'm trying to figure out if I can use the KPPACE KP-2100 camera as a desk electronics microscope. I want something I can mount to the ...
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30 views

Determining lens and sensor distance for narrow focus

I have the following items: a round target object, approx. 6mm in diameter a lens, focal length 20mm, F/2.8 a camera sensor, optical size 1/4" (note: I know this camera has a fixed-at-infinity lens, ...
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26 views

Would Camera Obscura work in low light conditions?

If I were to attempt to create a camera obscura affect in order to capture an image of the stars, or an aurora, would I still be able to get a decent one despite the relatively lower lighting ...
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49 views

Unable to get interference from milk using Time domain OCT (Michelson Morley interferometer) approach

I was able to construct time domain Optical coherence tomography based on Michelson Morley interferometer using a LED. While testing the interferometer, I used glass slide, layers of scotch tape. I ...
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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, ...
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How to add protective enclosure around exposed thermal camera

First off, let me state that I'm not entirely sure this is the right forum for this question. This was the only section I found multiple questions pertaining to thermal imaging, however, so I thought ...
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How can I correct a projector's magnification with a simple lens?

I am struggling with a real-life optics problem. At work, I have a projector that makes an image too big for the screen. I think I can reduce the image to the required size by mounting a simple lens ...
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How to calculate minimum optical power required from datasheet of camera sensor?

How can I determine from the datasheet of a camera sensor the minimum optical power required to see a spot on the image? I have 2 lasers with a diameter of 0.35 mm with respectively a power of 12nW/...
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20 views

How loud does a sound need to be to make pressure waves detectable by a camera?

I've seen Veritasium's video that describes how sound can be picked up by a camera by observing small movements of objects sensitive to pressure changes (bag of chips, aluminium foil, paper...). That ...
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171 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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288 views

How does the diaphragm in a camera work?

I think I am quite good at math and understand basic geometry, but I have problems understanding the function of a diaphragm in cameras. Let's say a camera is in a specific state. It captures the ...
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Can I calculate the size of a real object by just looking at the picture taken by a Camera?

Can I calculate the size of a real object by just looking at the picture taken by a Camera? (I think people do that) i dont understand how? (from physics point of view)
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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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Does 'focal length' mean something different with lenses and pinhole cameras?

Sometimes different but related things have the same name by some tradition or accident, causing a lot of headache to newcomers to a field. I would like to come to clear terms with this: does the ...
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40 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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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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1answer
48 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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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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2k 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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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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1answer
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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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21 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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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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35 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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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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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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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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2k views

Why is TV remote's infrared wave shown by a camera as purple light, why not red or something else?

I've always seen that all the old model remotes that is used in DVD players or TVs, it emits electromagnetic waves, having wavelength somewhere in the Infrared region. But when my phone's average ...
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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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7answers
5k views

The rule breaker, emissivity + reflectivity = 1

If emissivity and reflectivity are inversely proportionate, why does glass have a high emissivity of around 0.95-0.97 as well as being very reflective for IR Radiation? normally it works but not with ...
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Cameras in Voyager probes

I've always wondered about the cameras in the space probes, especially in the Voyagers. 1) What kind of cameras do they have? Digital? (Electronic - what kind of sensor and megapixel count?) Analog? (...
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346 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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Why do cameras have double lenses?

I was wonder why cameras the good ones have two lenses instead of one? what benfit does it carry with this fact? I have told that old cellular phones have camera with one lens and hence it blurring ...
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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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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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36 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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65 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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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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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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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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3k views

Land proportions in NASA blue marble photographs

What is the explanation for the apparent size difference of North America in these two photos from NASA? Image source Image source
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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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68 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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506 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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763 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: ...