![]() The saturation capacity actually used for the characterization of a camera is measured differently and directly from camera images. The value is typically smaller than the full-well capacity. This difference might cause discussion if comparing imaging sensor data and camera data. If a pixel is over-exposed it is set to maximum DN and it does not contain useful information.Ģ) Absolute sensitivity threshold (AST) A high saturation capacity allows for longer exposure times. The absolute sensitivity threshold describes the lowest number of photons (minimum detectable irradiation) where the camera can differentiate useful image information in a picture from noise. This means, the lower the threshold, the more sensitive the camera. You should take the AST into account in very low light applications. It is more significant than only referring to the QE, as the AST combines QE, dark noise, and the shot noise (which is caused by the quantum nature of the photons). The value is determined from the value where SNR is equal 1 (signal is as large as noise).Įven if the sensor is not illuminated each pixel shows a (dark) signal. With increasing exposure time and temperature electrons are generated in each pixel without light. Which is called dark noise (measured in electrons). A lower dark noise is preferred for most applications. The dark noise together with the photon shot noise and the quantization noise describe the noise of the camera. The dynamic range (DR) is the ratio between saturation irradiance and the minimum detectable irradiation. Cameras with a high DR are able to give more detailed image information for dark and bright areas in a single image at the same time. So a high DR is especially important in applications with dark and bright areas in one image or with rapidly changing light conditions. Physical processings within a sensor / a cameraĪn imaging sensor converts photons into electrons. The conversion ratio, the quantum efficiency (QE), depends on the wavelength. ![]() The values measured in a camera can differ from image sensor supplier data, as a camera might use a cover glass or filters.Ħ) Maximum Signal-to-Noise Ratio (SNRmax) The more photons are converted into electrons, the more sensitive to light the sensor is and the more information can be obtained from the image. The signal-to-noise ratio (SNR) is the ratio between the grey value (corrected for the dark value) and the signal noise. SNR increases with the number of photons. The maximum SNR (SNRmax) is reached for the saturation irradiance.Ī camera converts the electrons (e –) from the image sensor into digital numbers (DN). This conversion is described by the overall system gain K, measured in digital number (DN) per electron (e –). K electrons are required to increase the grey level by 1 DN. The K-Factor depends on the camera design. A slightly increased K-Factor may improve linearity at the cost of saturation capacity.The cost of CMOS image sensor pixel-based digital camera systems is being reduced through the use of smaller pixel sizes and larger fill-factors. However, CMOS pixel size reduction is only acceptable without sacrificing image quality. As CMOS pixel sizes continue to decrease, there is a reduction in image signal to noise as well as an increase in cross-talk between adjacent sensor pixels. These effects can be offset by careful design optimization through computer simulation. In this topic we discuss the contributions to the dark current noise source, and the simulation techniques required for the dark current and dark current shot noise calculations. The main starting point for them all is the Magazine Rack on the site.Open the file cis-dark.ldev and set the sense and tx voltages to 3.3V and run a single simulation. newspapers, glamour magazines and the like on the Archive website as well. If you still have an Amiga or C-64 around, or any other classic home computer, then you may find some of the magazines quite useful as they offer tips, tricks and information. The same applies if you like to tinker with classic computer systems. If you play classic computer games for instance, you may find useful information listed in those magazines as many came out during that time. While many may read them to relive the fascination they provided in their past, others may find them useful even today. You can filter magazines by language and other parameters, use search, and read any of the magazines online, or download them to your local device instead for offline viewing. The archive uses the same design and layout as the computer magazines archive. You find magazines for home computers, PC, but also classic consoles in all kinds of languages. ![]() The Game and Gamer Magazines archive on the other hand features game related magazines only.
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