Types of Image Sensor Exposures

I. Global Shutter

Operating Principle:

The global shutter refers to the simultaneous start and end of exposure for pixels on the image sensor at the same moment. During the exposure period, the image sensor converts the received light signals into electrical signals and stores them in the capac of each pixel.

After the exposure ends, the image sensor reads out the electrical signals stored in the capacitors of each pixel in sequence and performs subsequent signal processing image generation.

Advantages:

No motion distortion: Since all pixels start and end exposure at the same time, there is no motion distortion caused by different exposure of different pixels when shooting fast-moving objects.

Suitable for high-speed shooting: The global shutter can achieve very short exposure times, making it suitable for shooting high moving objects or scenes that need to be quickly captured.

Disadvantages:

Low fill factor: To achieve the global shutter function, the image sensor needs to integrate storage capacitor and a control circuit in each pixel, which reduces the fill factor of the pixel and thus affects the sensitivity and signal-to-noise ratio of the imageHigh cost: The manufacturing process of global shutter image sensors is relatively complex and expensive.

II. Rolling Shutter

Operating Principle:

The rolling shutter refers to the of the image sensor's pixels row by row, from top to bottom. During the exposure period, each row of pixels converts the received light signals into electrical signals stores them in the capacitors of that row of pixels.

After one row of pixels has finished exposing, the image sensor reads out the electrical signals stored in theitors of that row of pixels and performs subsequent signal processing and image generation. Then, the next row of pixels begins to expose, and so on, until all pixels on the entire image sensor have completed the exposure.

Advantages:

High fill factor: Since the rolling shutter does not require the integration of storage capacitors and circuits in each pixel, the fill factor of the pixels is higher, and the sensitivity and signal-to-noise ratio of the image are relatively higher.

Low cost The manufacturing process of rolling shutter image sensors is relatively simple and inexpensive.

Disadvantages:

Motion distortion: Since the exposure times of each row of pixels are different there is motion distortion caused by the different exposure times of different rows of pixels when shooting fast-moving objects. For example, when shooting a rapidly rotating fan, the of the fan may appear distorted.

Not suitable for high-speed shooting: The exposure time of the rolling shutter is relatively long, making it unsuitable for shooting high moving objects or scenes that need to be quickly captured.

III. Hybrid Shutter

Operating Principle:

The hybrid shutter is an exposure method that combines the advantages of both global shutter and shutter. In hybrid shutter mode, some pixels on the image sensor are exposed using the global shutter method, while other pixels are exposed using the rolling shutter method.

ically, the central region of the image sensor uses the global shutter method to ensure that there is no motion distortion when capturing fast-moving objects. Meanwhile, the peripheral of the image sensor use the rolling shutter method to improve the fill factor of the pixels and the sensitivity of the image.

Advantages:

Balances the advantages of and rolling shutters: Hybrid shutter can, to some extent, balance the advantages of both global and rolling shutters. It can not only achieve motion distortion-free but also improve the fill factor of the pixels and the sensitivity of the image.

High flexibility: Hybrid shutter can be flexibly adjusted according to different shooting needs. example, the proportion of global shutter and rolling shutter can be adjusted to adapt to different shooting scenes.

Disadvantages:

Complex design: The design of the hybrid is relatively complex. It requires integrating different types of shutter circuits and control logic into the image sensor, which increases the design difficulty and cost of the image sensor.

signal processing: Since different parts of the image sensor use different exposure methods in hybrid shutter mode, the subsequent signal processing and image generation processes need to separately process and the signals from different parts, which increases the complexity of signal processing.