Tuesday, August 21, 2018

LED Flicker Tutorial Paper

IE 2008 publishes a paper "LED flicker: Root cause, impact and measurement for automotive imaging applications" by Brian Deegan, Valeo Vision Systems.

"In recent years, the use of LED lighting has become widespread in the automotive environment, largely because of their high energy efficiency, reliability, and low maintenance costs. There has also been a concurrent increase in the use and complexity of automotive camera systems. To a large extent, LED lighting and automotive camera technology evolved separately and independently. As the use of both technologies has increased, it has become clear that LED lighting poses significant challenges for automotive imaging i.e. so-called "LED flicker". LED flicker is an artifact observed in digital imaging where an imaged light source appears to flicker, even though the light source appears constant to a human observer. This paper defines the root cause and manifestations of LED flicker. It defines the use cases where LED flicker occurs, and related consequences. It further defines a test methodology and metrics for evaluating an imaging systems susceptibility to LED flicker."

Sunday, August 19, 2018

Reports: CMOS Sensors in Short Supply, Prices Rising

IFNews quotes Chinese sites HQEW, EEPW, UDN, that refer to Taiwan Economic Times reporting that image sensors are in short supply now. This follows the shortages of capacitors, resistors, discrete MOSFETs, lenses, AF motors, and other components in the recent months. In case of image sensors, the main reason is said to be the growing adoption of dual- and triple-camera smartphones. Sony and Omnivision are increasing their image sensor prices. The smaller smartphone manufacturers, being unable to secure Sony, Omnivision, and Samsung sensors, are shifting their orders to Pixart and Silicon Optronics (SOI) as the cheaper alternatives.

LWIR Polarization Imaging

Polarization imaging starts finding some use in thermal cameras. Swedish Symposium on Image Analysis paper "A polarimetric longwave infrared imager" by Johan Eriksson, David Bergström, and Niclas Wadströmer from FOI Swedish defense research agency shows some advantages that polarization gives for thermal cameras:


Thanks to AB for the pointer!

DB Hitek Roadmap

DB Hitek (former Dongbu) foundry develops SPAD and GS pixels, as shown on its recent roadmap:

Saturday, August 18, 2018

Samsung Proposes Very Low Power 12Gbps CIS Interface

MDPI Sensors publishes "A 12-Gb/s Stacked Dual-Channel Interface for CMOS Image Sensor Systems" paper by Sang-Hoon Kim, Hoon Shin, Youngkyun Jeong, June-Hee Lee, Jaehyuk Choi, and Jung-Hoon Chun from Sungkyunkwan University and Samsung, Korea.

"We propose a dual-channel interface architecture that allocates high and low transition-density bit streams to two separate channels. The transmitter utilizes the stacked drivers with charge-recycling to reduce the power consumption. The direct current (DC)-coupled receiver front-end circuits manage the common-mode level variations and compensate for the channel loss. The tracked oversampling clock and data recovery (CDR), which realizes fast lock acquisition below 1 baud period and low logic latency, is shared by the two channels. Fabricated in a 65-nm low-power complementary metal-oxide semiconductor (CMOS) technology, the dual-channel transceiver achieves 12-Gb/s data rate while the transmitter consumes 20.43 mW from a 1.2-V power supply."

Friday, August 17, 2018

Intel-Mobileye AV Platform Uses 12 Cameras and 6 LiDARs

Intel publishes a 1-pager on its autonomous vehicle platform:

"There are 12 cameras in a 360-degree configuration. Eight cameras support self-driving and four short-range cameras support near-field sensing for self-driving as well as self-parking. The camera is the highest resolution sensor (hundreds of millions of samples per second) and is the only sensor capable of detecting both shape (vehicles, pedestrians, etc.) and texture (road markings, traffic sign text, traffic light color, etc.). Advanced artificial intelligence and vision capabilities are able to build a full-sensing state from the cameras. This end-to-end capability is critical to achieve “true redundancy” in combination with other sensor types.

There are six total “sector” lidars; three in front and three in rear. Lidar sensors are useful in detecting objects by measuring reflected laser light pulses. Lidar, in combination with radar, is used by the system to provide a fully independent source of shape detection. It works in addition to the camera system. Given our camera-centric approach, lidar only needs to be used for very specific tasks, primarily long-distance ranging and road contour. Limiting the workload for lidar results in much lower cost compared to lidar-centric systems; it also provides easier manufacturing and volume at scale.
"

Is 3D-Capable Smartphone the Next Big Thing?

EETimes reporter Junko Yoshida publishes a 10 page-long article "Jury Still Out on 3D Sensing for Smartphones" mostly based on an interview with Pierre Cambou, Yole Developpement analyst. Few interesting quotes:

"The industry verdict on 3D sensing [inside smartphones] varies widely — from “why bother?” to “it’s the future.” While some interpret the lack of iPhone X competitors with full-blown 3D sensing technology as a lack of market interest, others disagree.

While Apple’s TrueDepth had by 2017 established the trend for 3D front-facing cameras, Yole acknowledged that the wave [for 3D sensing adoption] “has started on the conservative side in terms of volume.”

The 3D sensing argument took a positive turn when Chinese smartphone OEMs including Xioami, Oppo, and Vivo unveiled their plans for 3D sensing over the last few months. Although Cambou is sure about front-facing 3D, he remains skeptical of use cases for 3D in rear-facing cameras. Pointing out a lack of momentum for VR and AR, he explained that neither the augmented reality sales pitch nor augmented gaming are yet proven on the market.

Recent quarterly financial calls held by STMicroelectronics and ams revealed that “they are almost overly confident” that 3D sensing will go inside both the front and rear cameras of smartphones, observed Cambou.

So what percentage of smartphone cameras will have 3D cameras? What’s the penetration ratio? Yole predicts that a 1.4% penetration ratio in 2017 will grow to 55% in 2023.

Huawei... is making a big investment in digital photography, said Cambou. In comparing the size of active matrix (used for traditional photography), he calculated that Apple is devoting only 52 mm², while Samsung has committed to 91 mm² and Huawei 112 mm².
"

Thursday, August 16, 2018

Gratings for 3D Sensing

Synopsys publishes a presentation on "Design of Gratings for 3D Depth Sensing" by Tung Yu Su, Richard Hu, and Morgan Lu, Cybernet System Taiwan.

Panasonic Long-Range ToF Sensor Article

Nikkei publishes an article on Panasonic 250m-range ToF solution, first presented 2 months ago.

"Panasonic Corp developed a range image sensor that can take an image of a 10cm object located 250m away in the dark. [there is no info on the range and resolution in a bright sunlight - ISW]


In the field of autonomous driving, the company considers that the sensor can supplement the functions of existing sensors because the new sensor (1) supports a longer distance than LiDAR (light detection and ranging), which enables to obtain range images, and (2) can take images in the complete dark unlike CMOS image sensors.

Panasonic expects to start to ship samples in fiscal 2019 and begin volume production in fiscal 2021.

...the new sensor uses a principle similar to the principle of flash-type LiDAR. In other words, near-infrared-light pulse (wavelength: 940nm, output: 1,200W, pulse width: 10ns, GaAs-based laser device in the case of the prototype) is applied to the entire imaging area.

With the prototype, near-infrared pulse is emitted with a cycle of 167μs to measure distance for each distance range. Based on a calculation conducted by Panasonic, when the viewing angle of the prototype is set at 20°, the number of photons coming from a distance of more than 100m away and entering one pixel is 1 or less. Therefore, in the case of a distance from which the number of incoming photons becomes 1 or less, measurement is carried out several times for the same distance range.
"

ToF APD sensor with 260,000 11.2μm2 pixels

Wednesday, August 15, 2018

SmartSens Raises 10s of Millions Dollar in a New Financing Round

SmartSens reports that it has closed a new investment round of "tens of millions of dollars". The lead investor is the National Core Industry Investment Fund (Big Fund), the Beijing Core Dynamic Energy Investment Fund, and venture capital institutions such as Lenovo Venture Capital Group.

Li Sheng, COO of SmartSens, said: “SmartSens has successfully completed a new round of financing, which reflects the recognition of the capital market. This recognition is not only derived from the achievements of SmartSens in the past, but also from the deep technical accumulation of SmartSens and becoming a global Leading high-performance image sensor supplier's grand vision."

SmartSens and IBM have reached an IP cooperation agreement in July 2018 - SmartSens will receive a total of 14 categories of more than 40 CMOS image sensor related patents. The patents involved are mainly basic technology patents, covering pixel design, semiconductor processing and manufacturing, and chip packaging.

"CIS is a key area for the future development of the semiconductor industry. Under the background of the government's support for local chip companies, the development prospects of SmartSens are undoubtedly worth looking forward to," Core Dynamics Investment Director Manager Wang Jiaheng said. "Core kinetic energy investment will.. continue to help SmartSens's technological innovation and market operation level, and make SmartSens a unicorn enterprise in China's semiconductor industry."

Wang Guangxi, Managing Director of Lenovo Ventures, said: "In the era of smart Internet, with the rise of 5G, Internet of Things, artificial intelligence and edge computing, the importance of image recognition has become more prominent. CIS chips are key components in the field of image recognition. Machine vision, intelligent transportation, autonomous driving, AR/VR and other fields are widely used, and it is a model application of technology innovation and industry integration. We are very optimistic about the development prospects of SmartSens, and are willing to help SmartSens through Lenovo's deep scientific resources and industrial advantages. Become a force that cannot be ignored in the CIS market."