27

When I have a camera, that can take still images at 10fps with a mechanical shutter, why doesn't it mean the sensor can take images at 10fps electronically without producing rolling shutter? In order to understand why, we have to take a look at a typical 3T(ransistor) pixel: This 3T pixel can be used with rolling shutters, but not with (electronic) global ...


16

It comes down to market size. Where is the demand for such cameras and do the number of sales justify the production set up costs? You can get an infra red conversion to standard type DSLR cameras (eg Do It Yourself Digital Infrared Camera Modification Tutorials) and you can convert the camera to a 'full spectrum' type which takes in some ultra violet. (see ...


16

There are two parts to this: First, rolling shutter can still occur with (some, see note) mechanical shutters. However, this is only at short exposure times. The shutter is built out of two curtains. Before the exposure, curtain 1 is in front of the sensor. When the exposure starts, curtain 1 moves down (or up or whatever) and starts exposing the sensor. At ...


8

First of all: standard CCD sensors are sensitive to wavelength far beyond 700nm. As much as I know Si-sensors are even more sensitive for near-IR light than for visible light. Of course it changes for much larger wavelengths: One condition for light being detectable is that photons have enough energy to create a hole-electron-pair. This energy threshold is ...


6

From a purely MTF (Modulation Transfer Function) point of view the operations you describe are identical. Adding the same pixels in the analog domain or the digital domain will give you the same spatial results with it's blurring, Moire fringes and other artifacts. In terms of noise it very much depends upon how well you are digitizing the signal. A CCD ...


6

Placeholder's valid comments notwithstanding, the noise you are seeing is indicative of a timing skew problem among the digital bits coming out of the ADC. Instead of xxx10000 and xxx01111, you are occasionally getting xxx00000 and xxx11111. I see the clock going into the ADC, but I don't see the next place in the datapath where the data is clocked again. ...


6

Both your existing answers are valid, but may be taken in combination: Simple Si sensors are good for visible and NIR and are common and therefore cheap. Modifications to the imaging system are required in many cases as the IR is normally blocked because it's undesirable. See for example Canon's EOS 20Da. Silicon sensors are fairly easily adapted to UV use ...


6

No, it simply is not capable in any way. The F103 MCU has a maximum frequency of 72 MHz so it cannot do anything past that, and it has no DCMI camera interface to assist in receiving parallel video data either.


5

For both visible and bolometer type, the reason they are cheap is because they can leverage the economies of scale in the silicon business. As soon as you get out into wavelengths (i.e. energies) that need other technologies (InGaAs as mentioned, InSb) you're talking 2" and 3" wafers at best, nothing like the pizza sized silicon wafers used to make chips ...


4

Lux is a photometric unit, energy units are radiometric units and the two are related through the response of the human eye. The Lux will nominally have the same units as the radiometric units but it will be weighted by the "typical" eye response. To make things easier to understand/compare when ever you see Lux think the radiometric terms in equivalence. ...


4

The light conversion element in most image sensors as actually a reverse biased diode carefully crafted to retain charge until reset. A photon enters the bulk of the photodiode and interacts with the Silicon lattice creating a electron/Hole pair. The electric field within the diode from being reversed biased sweeps the minority carrier away while the ...


4

The Kinect camera is NOT a TOF (time-of-flight) camera. Instead, it projects "structured light" (a pseudorandom pattern created by an IR laser and a hologram) into the scene, and analyzes the image it gets back through a second (IR) camera in order to determine depth.


4

The Fraunhofer Institute for Integrated Circuits IIS (Design Automation Division EAS) researches "Vision System on Chip" (VSoC) devices. The current devices is a 1 MegaPixel CCD image sensor with analog pre-processing in the columns configurable ADC post-processing in a FPGA and high-level processing in an ARM dual-core CPU (Xilinx Zynq-7000 platform). ...


4

Microbolometers are inherently more expensive than other silicon ICs specifically because of their required 3-dimensional structure. In order to suspend the sensor pixels on thermal bridges the sensor layer has to be put on a substrate that is subsequently etched out from underneath the ~17-micron panels. Many procedures that are commonly used on CMOS to ...


4

Is it guaranteed that fingerprint data taken by a scanner can be reused by another scanner? No. (I'd really love to write a longer answer, but there's simply not much to it – such systems are proprietary, depend on the properties of the actual sensor, the algorithms used to process the sensor data, the algorithms used to compare fingerprints, and the ...


4

In general, image quality will drop rapidly. The sensor circuitry is carefully designed to minimize internal noise and crosstalk, but it is usually optimized for the specified master clock frequency range. The usual method to get high frame rates on sensors that allow it, is to read out only a tiny portion of the sensor area for each frame. In other words, ...


4

Yes, what you suggest is possible. (Congratulations on your cogent thought process). The mouse navigation compares "features" from one image frame to the next, and calculates how much X-movement and Y-movement has transpired. If no image features can be found, then no movement can be calculated. An out-of-focus image contains no features: a mouse's lens is ...


3

You have got the nomenclature correct. A module contains an imager and lens and focussing element. Most of these imagers operate over an I^2C bus for control and a MIPI bus for the data flow. If your controller supports those interfaces it will be as simple as just connecting them. There are imagers that use other interfaces (Parallel , Analog) but these ...


3

For CCDs: - It's hard to clock the horizontal shift registers of a CCD much faster than 40 MHz without having a drop in you CTE (Charge transfer efficiency) as there is a limited drift velocity for electrons. The fastest I've even worked with is ~ 45 MHz, and I was cheating. How this problem is solved is to use a "tapped" architecture in which a subset of ...


3

Digital camera sensors do achieve a steady state, and how quickly depends on the system noise, both electrical and thermal. The steady state is a saturated sensor, or all white in photo terms. This happens if the shutter is open or closed. The sensor has to be read or refreshed just before each photo. For CMOS sensors noise can overwhelm the signal in a ...


3

I realize this question is old, but I thought I'd comment on an interesting solution, built by some students from the Universidad de la República in Uruguay. An overview of their tablet can be found here. Basically, they solved the problem by attaching both an infrared and ultrasound emitter to the tip of the pen. The receiver is best described as having ...


3

You might want to read about the Kepler spacecraft's CCD readout system. Monitoring thousands of stars at a time continuously, with 42 CCD chips, is just too much data. It doesn't take conventional 2D images but reads out only the CCD cells in areas of interest. Sounds sort of like what you're asking about. Basic info http://kepler.nasa.gov/Mission/...


3

Individual LEDs can be used as light sensors: they behave like photodiodes. OLEDs are potentially capable of behaving like this as well (they're also semiconductors), but I can't find reports of anyone having tried it. It's probably extremely inefficient. LCDs cannot: they operate by applying a field to twist the crystals, and there's no photosensitivity ...


3

The diagram shown is what is inside the CCD, so you don't need to choose any transistors. In fact, you couldn't possibly choose any transistors in the outside world that would work. Let's put some facts/reference data up first. - Scope probe is ~10 pF - Most pins on an IC package at minimum are ~ 1 pF It is entirely possible to have a CCD detect single ...


3

A top quality demosaic process is fraught with subtlety, but very cheap answer can be had if you can accept a 50% loss in spacial resolution. Simply sum groups of four sensor pixels to get a single grey pixel. Assuming your sensor has a "typical" Bayer filter pattern, there will be twice as many green sensors as either red or blue. Summing square groups of ...


3

The kinnect uses an array of ir LEDs, actually it's a single chip array I think. This outputs a grid pattern. They bought two companies with this tof tech. On seems to work by modulating the brightness of these LEDs with an rf carrier. So maybe a dc voltage to keep LEDs lit, then a carrier is added in on top of that. Then they use a high, 160fps, ...


3

There is no easy simple answer to this question. The first thing to say is clock frequency is not really that important. For years people believe that the higher clock frequency the faster the processor is, and this is not true. What you can say is that if you have a particular processor chip and you clock it at a frequency, and then you increase that ...


3

The data bandwidth you mentioned is certainly part of the calculation, but only the beginning: the FPGA and the camera module need a compatible interface that can reach the required speed. Whether your processing pipeline can be realized depends very much on your definition of "basic image processing". Ideally your algorithm is parallelizable so you can ...


3

I found this link here for the fine details. Scientific CMOS (sCMOS) Unlike previous generations of CMOS and CCD-based sensors, sCMOS is uniquely capable of simultaneously offering: Extremely low noise Rapid frame rates Wide dynamic range High quantum efficiency (QE) High resolution Large field of view Performance highlights ...


3

It uses a Photonic Mixer Device. The REAL3 imager uses a sensor from pmd technologies(see the bottom of that page). PMD technologies is named for their use of Photonic Mixer Device technology. As you speculated, it does use pulsed light. Specifically, it modulates the outgoing beam with an RF carrier and then measures the phase shift of the return signal. ...


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