Omnivision Tacks on Two Global Shutter Sensors to Near-infrared Family
The two new global shutter image sensors from Omnivision aim to expand the availability of in-cabin monitoring solutions.
In the automotive technology industry, much of the media attention tends to center on advanced driver assistance technology (ADAS) and autonomous tech. A less popular but still important technology is in-cabin monitoring systems, which are emerging as a new means of ensuring driver and occupant safety. Many of these systems rely on cameras and other sensing technologies to track the state and movements of cabin occupants.
Omnivision has added two new global shutter sensors to its Nyxel near-infrared (NIR) technology family. Image courtesy of Omnivision
This week, Omnivision announced the release of two new global shutter in-cabin sensing solutions. In this piece, we’ll discuss rolling versus global shutter for imaging sensors and take a look at the details of Omnivision's newest products.
Rolling vs. Global Shutter
In CMOS imaging sensors, there are generally two distinct sequences through which an image can be read: rolling shutter or global shutter.
Rolling shutter systems expose different parts of the image sequentially instead of all at once. In these systems, images are exposed either row by row or column by column, starting at the first row or column of the image and then moving on to the next one until the entire frame is captured. In the case of a video, this process is then continually repeated for each frame of the video.
Global versus rolling shutter image exposure. Image courtesy of Oxford Instruments
Rolling shutters are cost-effective to implement and can take images at much faster speeds. On the other hand, the sequential nature of rolling shutter image sensors means that they can suffer from visual defects when capturing fast-moving objects.
Unlike rolling shutters, global shutters are image sensors that capture an image by exposing the entire image sensor at the same time. By activating all pixels at once, a global shutter removes the visual defects that are associated with rolling shutter sensors. However, global shutters tend to have the disadvantage of lower frame rates and higher read-out noise.
Omnivision Unveils New Global Shutter Sensors
This week, Omnivision announced two new global shutter image sensors for automotive in-cabin sensing applications.
The first of the two products is the OX02C1S, a 2.5‑megapixel RGB‑IR global shutter solution. The device consists of pixels sized 2.2 µm × 2.2 µm arranged in a 1920 × 1280 array and achieves a 1/3.52‑inch optical format. The product supports either a parallel 10-bit data output or a high-speed serial data transfer with MIPI CSI-2. Notably, the OX02C1S features a quantum efficiency of 36% and a significant increase in modulation transfer function over the previous generation of products.
Block diagram of the OX02C1S. Image courtesy of Omnivision
Omnivision's other new product is the OX01H1B, which is a very similar offering to the OX02C1S, but comes in a lower 1.5 MP resolution and 1/4.51‑inch optical format. The two devices share a 2.2 µm pixel size, 36% quantum efficiency, and interface capabilities. Additionally, both products include integrated image signal processing blocks with features such as defective pixel cancellation, automatic black level correction, and automatic exposure/gain control. Both products are also ASIL-B certified.
All things considered, Omnivision is positioning the OX02C1S as a low-cost yet high-performance solution for driver monitoring systems, while the OX01H1B is meant to be a more flexible solution for vehicles with unique interior designs. Between the two products, Omnivision hopes it can provide automotive designers with the image-sensing solutions needed for any design or system.