From Higher Resolution to Zero Motion Artifacts—Image Sensors Keep Evolving
Leveraging CMOS and advanced pixel-binning technologies, the industry is offering image sensors that target use cases in ADAS, smartphone cameras, surveillance systems, and more
With the advancement in CMOS and pixel-binning technologies, companies are now manufacturing image sensors that eliminate motion artifacts and boast higher resolution, better dynamic range, and higher performance.
This article discusses some of the new image sensor products that have been introduced lately in the industry.
Pixel-binning Technology Takes Center Stage
Because small pixel sizes can’t capture as much light, making a superpixel with pixel-binning technology solves this problem. Pixel-binning is the process of taking adjacent pixels in an image sensor and grouping them together to form a cluster of superpixels. What’s more, pixel binning technology increases the light sensitivity of the pixels to produce clearer low light pictures with less noise.
Close-up view of the ISOCELL HP2 image sensor. Image used courtesy of Samsung
Samsung recently leveraged its pixel-binning technology, Tetra2pixel, to manufacture a 200MP image sensor, ISOCELL HP2. The image sensor allows phone makers to develop devices such as smartphones with higher-resolution cameras. Embedding 200-million 0.6-micrometer (μm) pixels in a 1/1.3” optical format, the ISOCELL HP2 finds applications in 108 MP main smartphone cameras.
Samsung’s Tetra2pixel technology enables the image sensor to work optimally in different light conditions including low-lit environments. For instance, in a low-lit environment, ISOCELL HP2 automatically merges adjacent pixels into one, allowing it to operate as a single 1.2 µm-sized pixel with 50 MP or 2.4 µm-sized pixel with 12.5 MP.
The number of electrons that a single pixel in an image sensor can absorb decreases as pixel size decreases. This affects the quality of color reproduction in a captured image. To boost the performance of the image sensor by 33%, Samsung adopted dual vertical transfer gate (D-VTG) technology to enable pixel stores more electrons and also eliminate the production of washed-out pictures when operated in a bright environment.
Samsung also includes a Super QPD feature in the image sensor. This enables the sensor to use all its 200-million pixels for focusing agents in low-lit settings. The ISOCELL HP2 boasts a high frame rate and reduced shutter lag. This allows a faster picture-taking experience. The image sensor is adopted in the latest Samsung S23 Ultra smartphone.
Eliminating Motion Artifacts in in ToF Cameras
Motion artifacts can occur due to the relative motion between an object and a time of flight (ToF) image sensor. To eliminate motion artifacts in a ToF camera, Teledyne has introduced Hydra 3D+, an image sensor that integrates a 10 μm three-tap pixel with excellent demodulation contrast.
Close-up view of the Hydra 3D ToF image sensor. Image used courtesy of Teledyne
The Hydra 3D+ is an 832 x 600-pixel resolution CMOS image sensor suitable for use in 3D detection and measurement. The device boasts high sensitivity in the near-infrared (NIR) wavelength range.
According to the company, Hydra3D+ captures fast-moving objects in real-time at short, mid and long-range distances without motion artifacts. Thus, the device finds applications in automated guided vehicles, surveillance, robot navigation and factory automation. More information is available in the Hydra3D+ product brief.
Key features in the image sensor include on-chip multi-system management, powerful on-chip high dynamic range (HDR), and programmable exposure time. With the new ToF sensor, the company says that consumers can enjoy 3D measurement with the highest levels of 3D performance, uncompromised image quality in both 2D and 3D modes, and in all distance ranges and conditions even where multiple systems operate or in outdoor environments.
High Dynamic Range CMOS Camera
Meanwhile, in January Canon released a 1.0-inch back-illuminated stacked CMOS image sensor which is targeted toward monitoring applications. Like Teledyne’s Hydra3+ image sensor, Canon’s new image sensor also captures images without motion artifacts.
Conventional image sensors perform high dynamic range image synthesis to produce a single image that is captured from multiple separate images under different exposure conditions. This operation is usually flawed with the occurrence of motion artifacts in the produced image.
To address this issue, the new CMOS sensor from Canon which is equipped with state-of-the-art multiple CPUs and other processing circuitry divides a single image into 736 distinct areas, each of which is set to the optimal exposure time based on the brightness level of the environment. This not only eliminates motion artifacts but also eliminates the need for image synthesis operations.
Canon’s CMOS sensor eliminates the need for image synthesis. Image used courtesy of Canon
The product boasts a high-speed image capture at speeds of approximately 60 frames-per-second (fps) and a high pixel count of approximately 12.6 million pixels. What’s more, the sensor records an industry-leading high dynamic range of 148 dB.
The device finds applications in environments where there are both bright and dark areas such as underground parking entrances and background monitoring at stadium entrances According to the company, the device captures images at light levels ranging from approximately 0.1 lux to approximately 2,700,000 lux.