An image sensor in a camera is a detector that allows the camera to convert photons (that is, light) into electrical signals the device interprets. Image sensor and camera families are module-level devices or components designed to capture visual information electronically in visible or infrared spectrums. These products consist of arrays of photosensitive elements linked to a shared control and interface mechanism. The products include standard still video and image capture and specialised applications, including thermal and spatial imaging.
Types of Image Sensors:
CCD and CMOS are the two standard and essential types of image sensors.
-
Charged-coupled device (CCD):
The CCDs are sensors based on passive photodiodes’ arrays, which integrate charge during the camera's exposure time. The resultant charge is then sent to electronics to read the accumulated charges of various pixels and translate them into voltages.
Features of the CCD Sensor:
The quantum efficiency is very high thanks to the passive pixel device of the CCD. This is especially good in applications where the light is poor. Additionally, high pixel uniformity can be achieved because the power dissipation is the same for all pixels (or at least for the pixels in the same column). On the other hand, switching rates are prolonged, so the low bandwidth (typically <20 fps) and technology output to CCD sensors is non-standard, making them quite expensive.
-
Complementary metal-oxide-semiconductor (CMOS):
The CMOS sensors are based on an array of active pixels: the pixel-level electronics (typically 3 or 4 transistors) translate the charge accumulated in the photodiode into a well-defined voltage; in this way, the output of each pixel needs only to be acquired and sampled.
CMOS is a sensor based on the active pixels’ array. Pixel-phase electronics (usually three or four transistors) convert the charge held in a photodiode into a greater extent of voltage. Each pixel’s output only needs to be recorded and sampled in this method.
Since pixel output depends on voltage, CMOS sensors allow higher frame rates to be achieved through easier reading and definition of the area of interest (ROI) to receive.
However, this reading method has the disadvantage of introducing more noise due to the reading by a transistor of each pixel and so-called noise inconsistencies (image deviations due to inconsistencies between different pixels).
Why Enrgtech?
Enrgtech carries an outstanding collection of image sensors for potential customers at affordable prices. We provide an eCommerce platform for the convenience of product supply and ensure that our state-of-the-art products are delivered to your doorstep at a single click in no time.
