scholarly journals Light-In-Flight Imaging by a Silicon Image Sensor: Toward the Theoretical Highest Frame Rate

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2247 ◽  
Author(s):  
Takeharu Etoh ◽  
Tomoo Okinaka ◽  
Yasuhide Takano ◽  
Kohsei Takehara ◽  
Hitoshi Nakano ◽  
...  

Light in flight was captured by a single shot of a newly developed backside-illuminated multi-collection-gate image sensor at a frame interval of 10 ns without high-speed gating devices such as a streak camera or post data processes. This paper reports the achievement and further evolution of the image sensor toward the theoretical temporal resolution limit of 11.1 ps derived by the authors. The theoretical analysis revealed the conditions to minimize the temporal resolution. Simulations show that the image sensor designed following the specified conditions and fabricated by existing technology will achieve a frame interval of 50 ps. The sensor, 200 times faster than our latest sensor will innovate advanced analytical apparatuses using time-of-flight or lifetime measurements, such as imaging TOF-MS, FLIM, pulse neutron tomography, PET, LIDAR, and more, beyond these known applications.

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2407 ◽  
Author(s):  
Anh Nguyen ◽  
Vu Dao ◽  
Kazuhiro Shimonomura ◽  
Kohsei Takehara ◽  
Takeharu Etoh

The paper summarizes the evolution of the Backside-Illuminated Multi-Collection-Gate (BSI MCG) image sensors from the proposed fundamental structure to the development of a practical ultimate-high-speed silicon image sensor. A test chip of the BSI MCG image sensor achieves the temporal resolution of 10 ns. The authors have derived the expression of the temporal resolution limit of photoelectron conversion layers. For silicon image sensors, the limit is 11.1 ps. By considering the theoretical derivation, a high-speed image sensor designed can achieve the frame rate close to the theoretical limit. However, some of the conditions conflict with performance indices other than the frame rate, such as sensitivity and crosstalk. After adjusting these trade-offs, a simple pixel model of the image sensor is designed and evaluated by simulations. The results reveal that the sensor can achieve a temporal resolution of 50 ps with the existing technology.


Sensors ◽  
2020 ◽  
Vol 20 (23) ◽  
pp. 6895
Author(s):  
Nguyen Hoai Ngo ◽  
Anh Quang Nguyen ◽  
Fabian M. Bufler ◽  
Yoshinari Kamakura ◽  
Hideki Mutoh ◽  
...  

The theoretical temporal resolution limit tT of a silicon photodiode (Si PD) is 11.1 ps. We call “super temporal resolution” the temporal resolution that is shorter than that limit. To achieve this resolution, Germanium is selected as a candidate material for the photodiode (Ge PD) for visible light since the absorption coefficient of Ge for the wavelength is several tens of times higher than that of Si, allowing a very thin PD. On the other hand, the saturation drift velocity of electrons in Ge is about 2/3 of that in Si. The ratio suggests an ultra-short propagation time of electrons in the Ge PD. However, the diffusion coefficient of electrons in Ge is four times higher than that of Si. Therefore, Monte Carlo simulations were applied to analyze the temporal resolution of the Ge PD. The estimated theoretical temporal resolution limit is 0.26 ps, while the practical limit is 1.41 ps. To achieve a super temporal resolution better than 11.1 ps, the driver circuit must operate at least 100 GHz. It is thus proposed to develop, at first, a short-wavelength infrared (SWIR) ultra-high-speed image sensor with a thicker and wider Ge PD, and then gradually decrease the size along with the progress of the driver circuits.


Author(s):  
Takashi Kakue ◽  
Tatsuki Tahara ◽  
Yuki Shimozato ◽  
Kenichi Ito ◽  
Yasuhiro Awatsuji ◽  
...  

We succeeded in high-speed imaging of gas flow by means of parallel phase-shifting digital holography. This technique is capable of capturing three-dimensional (3-D) information of object and carrying out phase-shifting interferometry with a single-shot exposure because the interference fringe images in which the information of multiple phase-shifted holograms is spatially multiplexed are simultaneously recorded. We constructed a high-speed phase-shifting digital holography system by employing a quarter-wave plate and a high-speed camera. The image sensor of the camera has an anisotropic polarization-detecting function pixel by pixel. Each pixel of the polarization-detecting function corresponds to each pixel of the image sensor. The phase retardation of the reference wave is determined by the direction of the polarization axis of the each pixel. A compressed gas flow sprayed from a nozzle was set as an object. We attained the reconstructed images of phase variation caused by the gas flow. We also succeeded in phase imaging at the rate of 180,000 frames per second when the number of pixels of the captured image was 128 × 128. Additionally, we also obtained temporal subtraction images of the reconstructed images. The achieved frame rate was the fastest among not only phase-shifting digital holography but also digital holography and phase-shifting interferometry which have been ever reported, for our knowledge. It is expected that parallel phase-shifting digital holography and the constructed system can contribute to 3-D moving picture measurement of dynamically moving objects such as particle flows, shock waves, mechanical vibration, and so on.


Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3713
Author(s):  
Soyeon Lee ◽  
Bohyeok Jeong ◽  
Keunyeol Park ◽  
Minkyu Song ◽  
Soo Youn Kim

This paper presents a CMOS image sensor (CIS) with built-in lane detection computing circuits for automotive applications. We propose on-CIS processing with an edge detection mask used in the readout circuit of the conventional CIS structure for high-speed lane detection. Furthermore, the edge detection mask can detect the edges of slanting lanes to improve accuracy. A prototype of the proposed CIS was fabricated using a 110 nm CIS process. It has an image resolution of 160 (H) × 120 (V) and a frame rate of 113, and it occupies an area of 5900 μm × 5240 μm. A comparison of its lane detection accuracy with that of existing edge detection algorithms shows that it achieves an acceptable accuracy. Moreover, the total power consumption of the proposed CIS is 9.7 mW at pixel, analog, and digital supply voltages of 3.3, 3.3, and 1.5 V, respectively.


Sensors ◽  
2020 ◽  
Vol 20 (13) ◽  
pp. 3649
Author(s):  
Minhyun Jin ◽  
Hyeonseob Noh ◽  
Minkyu Song ◽  
Soo Youn Kim

In this paper, we propose a complementary metal-oxide-semiconductor (CMOS) image sensor (CIS) that has built-in mask circuits to selectively capture either edge-detection images or normal 8-bit images for low-power computer vision applications. To detect the edges of images in the CIS, neighboring column data are compared in in-column memories after column-parallel analog-to-digital conversion with the proposed mask. The proposed built-in mask circuits are implemented in the CIS without a complex image signal processer to obtain edge images with high speed and low power consumption. According to the measurement results, edge images were successfully obtained with a maximum frame rate of 60 fps. A prototype sensor with 1920 × 1440 resolution was fabricated with a 90-nm 1-poly 5-metal CIS process. The area of the 4-shared 4T-active pixel sensor was 1.4 × 1.4 µm2, and the chip size was 5.15 × 5.15 mm2. The total power consumption was 9.4 mW at 60 fps with supply voltages of 3.3 V (analog), 2.8 V (pixel), and 1.2 V (digital).


Author(s):  
W. Meier ◽  
I. Boxx ◽  
C. Arndt ◽  
M. Gamba ◽  
N. Clemens

An experimental arrangement for the investigation of auto-ignition of a pulsed CH4 jet in a coflow of hot exhaust gas from a laminar lean premixed H2/air flame at atmospheric pressure is presented. The ignition events were captured by high-speed imaging of the OH∗ chemiluminescence associated with the igniting flame kernels at a frame rate of 5 kHz. The flow-field characteristics were determined by high-speed particle image velocimetry and Schlieren images. Furthermore, high-speed imaging of laser-induced fluorescence of OH was applied to visualize the exhaust gas flow and the ignition events. Auto-ignition was observed to occur at the periphery of the CH4 jet with high reproducibility in different runs concerning time and location. In each measurement run, several hundred consecutive single shot images were recorded from which sample images are presented. The main goals of the study are the presentation of the experimental arrangement and the high-speed measuring systems and a characterization of the auto-ignition events occurring in this system.


Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 3112 ◽  
Author(s):  
Vu Dao ◽  
Nguyen Ngo ◽  
Anh Nguyen ◽  
Kazuhiro Morimoto ◽  
Kazuhiro Shimonomura ◽  
...  

The paper presents an ultra-high-speed image sensor for motion pictures of reproducible events emitting very weak light. The sensor is backside-illuminated. Each pixel is equipped with the multiple collection gates (MCG) at the center of the front side. Each collection gate is connected to an in-pixel large memory unit, which can accumulate image signals captured by repetitive imaging. The combination of the backside illumination, image signal accumulation, and slow readout from the in-pixel signal storage after an image capturing operation offers a very high sensitivity. Pipeline signal transfer from the MCG to the in-pixel memory units enables the sensor to achieve a large frame count and a very high frame rate at the same time. A test sensor was fabricated with a pixel count of 32 × 32 pixels. Each pixel is equipped with four collection gates, each connected to a memory unit with 305 elements; thus, with a total frame count of 1220 (305 × 4) frames. The test camera achieved 25 Mfps, while the sensor was designed to operate at 50 Mfps.


Author(s):  
Wolfgang Meier ◽  
Isaac Boxx ◽  
Christoph Arndt ◽  
Mirko Gamba ◽  
Noel Clemens

An experimental arrangement for the investigation of auto-ignition of a pulsed CH4 jet in a co-flow of hot exhaust gas from a laminar lean premixed H2/air flame at atmospheric pressure is presented. The ignition events were captured by high-speed imaging of the OH* chemiluminescence associated with the igniting flame kernels at a frame rate of 5 kHz. The flow field characteristics were determined by high-speed PIV and Schlieren images. Further, high-speed imaging of laser-induced fluorescence of OH was applied to visualize the exhaust gas flow and the ignition events. Auto-ignition was observed to occur at the periphery of the CH4 jet with high reproducibility in different runs concerning time and location. In each measurement run several hundred consecutive single shot images were recorded from which sample images are presented. The main goals of the study are the presentation of the experimental arrangement and the high-speed measuring systems and a characterization of the auto-ignition events occurring in this system.


Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1086 ◽  
Author(s):  
Manabu Suzuki ◽  
Yuki Sugama ◽  
Rihito Kuroda ◽  
Shigetoshi Sugawa

In this paper, a prototype ultra-high speed global shutter complementary metal-oxide-semiconductor (CMOS) image sensor with pixel-wise trench capacitor memory array achieving over 100 million frames per second (fps) with up to 368 record length by burst correlated double sampling (CDS) operation is presented. Over 100 Mfps high frame rate is obtained by reduction of pixel output load by the pixel-wise memory array architecture and introduction of the burst CDS operation which minimizes the pixel driving pulse transitions. Long record length is realized by high density analog memory integration with Si trench capacitors. A maximum 125 Mfps frame rate with up to 368 record length video capturing was confirmed under room temperature without any cooling system. The photoelectric conversion characteristics of the burst CDS operation were measured and compared with those of the conventional CDS operation.


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