Archives for July 2017

Optimal Coding Functions for I-ToF Imaging

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University of Wisconsin-Madison and Columbia University publish a technical report "What Are Optimal Coding Functions for Time-of-Flight Imaging?" by Mohit Gupta, Andreas Velten, Shree Nayar, and Eric Breitach.

"Almost all current C-ToF systems use sinusoid or square coding functions, resulting in a limited depth resolution. In this paper, we present a mathematical framework for exploring and characterizing the space of C-ToF coding functions in a geometrically intuitive space. Using this framework, we design families of novel coding functions that are based on Hamiltonian cycles on hypercube graphs. Given a fixed total source power and acquisition time, the new Hamiltonian coding scheme can achieve up to an order of magnitude higher resolution as compared to the current state-of-the art methods, especially in low SNR settings."

The "geometrically intuitive hypercube graphs" look like this:

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Caeleste Gets New CEO

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Photonics: Caeleste has appointed Geert De Peuter as its new CEO. Geert De Peuter spent much of his career at Alcatel, now Nokia Bell Labs.

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Light Co. Starts Shipping its Computational Camera

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Light starts shipping the L16 camera to its pre-order customers, after 4 years of development. The company explains what it has accomplished in these 4 years:
  • It took us three years to design and build our own custom ASIC chips, which are needed to control all 16 camera modules at the same time.
  • We also developed our own 70mm and 150mm camera modules, complete with custom optics and electrical components. To put this in perspective, most smartphone cameras contain 30mm or 50mm lenses. The higher focal length lenses we were looking for weren’t even on the market yet, so we had to invent them ourselves.
  • We created proprietary image-fusing algorithms and processing pipelines that align each of the base camera modules.
  • We produced Android software to operate our camera and a Mac/Windows application for depth-of-field editing.
  • We implemented an e-commerce platform and initiated a complex global manufacturing and supply chain.

Light Director of Hardware Engineering, Brian Gilbert,
with the first 'lunch box' prototype
Light final product. Each lens is annotated
with its range of distances, focal length, and aperture

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TSMC Wafer Bonding Applications

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TSMC patent application US20170186798 "Stacked SPAD image sensor" by Ming-hsien Yang, Ching-chun Wang, Dun-nian Yaung, Feng-chi Hung, Shyh-fann Ting, and Chun-yuan Chen is said to improve SPAD pixel fill factor:


TSMC patent application US20170186796 "Frontside illuminated (FSI) image sensor with a reflector" by Min-feng Kao, Dun-nian Yaung, Jen-cheng Liu, Jeng-shyan Lin, Hsun-ying Huang, and Tzu-hsuan Hsu proposes wafer bonding to add a reflector 102 under the PD 104 to improve FSI pixel QE:

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5T Pixel in SPICE

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International Journal of Advanced Research in Computer and Communication Engineering publishes a paper "Optimized Design of Active Pixel Sensor using CMOS 180 nm Technology" by Dipti, Rajesh Mehra, and Deep Sehgal.

Contrary to the whole industry spending a lot of money on expensive device simulators, the authors simulate everything in SPICE:


The proposed timing sequence works well, just does not perform CDS and the small signals do not go through, not to talk about extra sensitivity to FD leakage:

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Column-Parallel ADC Theses

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Middle East Technical University, Ankara, Turkey, publishes MSc thesis "Column Level Two-Step Multi-Slope Analog to Digital Converter for CMOS Image Sensors" by Can Tunca.

The design is realized for pixel pitch of 6.7µm. Power consumption per column [12 bit] ADC is 88 µW and sampling speeds larger than 50kS/s is supported.

The outline of the operation of the Two-Step Integrating ADC is explained below and an example conversion sequence is illustrated in Figure 3.1.

  • In the first step, K-bit coarse conversion is performed using a ladder shaped ramp. When the decision is made, the ramp value is latched into a memory capacitor. Furthermore, the global counter value latched in the digital coarse memory block.
  • Secondly the residue between the latched ramp value and the input voltage is compared to the fine ramp in the L-bit fine conversion phase. Likewise, when the decision is made global counter value is latched into the digital fine memory block.
  • On the final step, coarse and fine conversion results are superimposed and fed to the output stage.


Milano Politecnico, Italy, publishes MSc thesis "Sigma-Delta Analogue-to-Digital converter for column-parallel CMOS image sensors" by Michele Sannino.

In this master’s thesis project a column-parallel ADC for high data-rate image sensors was designed using TowerJazz 0.18µm process.

The ADC was required to achieve 12 bits of resolution in the competitive conversion time of 1us. Other design specifications include a constraint on the maximum input noise, which had to be less than 100uVrms, and on the average power consumption, to be contained within 330uW. The converter, which was laid out in a column-parallel topology with 15um pitch, was also required to occupy an area smaller than 10,000um2 (hence its length should be smaller than 670um). Meeting this specification makes the ADC suitable to be implemented in a stacked chip in future developments, which would push further the limit of achievableframe-rate.


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Future of Mobile Imaging

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Engadget publishes an article "The future of the smartphone camera: where next?" There are no big revelations in the list of innovations:
  • Augmented reality
  • Dual-lens cameras
  • Better lenses
  • 4K recording
  • Thermal imaging
  • Optical zoom
  • 360 video
Meanwhile, Strategy Analytics sees mobile imaging future in 3D cameras:

"Sales of 3D Imaging smartphones are poised to take off. Advanced security and Augmented Reality (AR) solutions will be the main drivers. We predict that 3D Imaging will see over 1700% growth during next six years and will become one of the key differentiators in higher-end smartphones."

On the other hand, analysts do not give a significance to other stuff:
  • No interest in Visible Light Communication (VLC, LiFi)
  • No higher resolution push. 41MP in old Nokia phones remains the world's record forever
  • No high speed imaging future. Sony Xperia 960fps camera does not attract analysts attention

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HDR Pixel Thesis

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Glasgow University, UK, publishes a PhD thesis "High dynamic range image sensor using tone mapping operation" by Waqas Mughal. Here is the HDR pixel principle:

"WDR capture can be performed by introducing a monotonically increasing reference signal Vref. It is possible to capture high intensity information by comparing the integrated voltage at node N to a reference voltage Vref.

The pixel output follows a known reference signal, which is sampled and held at a value when the photo-generated signal on the diode becomes lower than the reference voltage. The potential at which these two signals are equal is recorded and is used as the pixel’s response. In the pixel, M1, M2, M3 and M4 are reset device, reference voltage switch, source follower and row select switch.
"


The Vref sweep function can be used for the tone mapping, once the pixel FPN issues are solved:

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Fujifilm Finepix XP120 review

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Fujifilm's FinePix XP120 is a waterproof camera that can dive to 20m and survive temperatures of -10c as well as drops from 1.75m. There's a 5x / 28-140mm zoom, 3in screen and Wifi. Ken compared it to the high-end Olympus TOUGH TG5 in his review. Find out which is your ideal waterproof camera!…

The post Fujifilm Finepix XP120 review appeared first on Cameralabs.

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SK Hynix 8-inch CIS Foundry Officially Starts as a Separate Business

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Korea Herald: SK Hynix foundry (SK Hynix System IC) starts operating as a separate entity, offering a "cost-effective CIS process":

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Mobile Imaging Report from China

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China Galaxy International publishes it analysis on mobile imaging industry in China.

"Currently, Sony dominates the smartphone CMOS image sensor market with over a 35% market share in 2016, followed by Samsung with a 19% market share and Omnivision with a 12% market share.

The lens market is dominated by Largan Precision [3008.TT], Sunny Optical [2382.HK] and Genius Electronic Optical [3406.TT]. The total market share of these three companies was 53.3% in 2015. Currently, most smartphone cameras are equipped with 6P lenses. Only Largan Precision can achieve a decent defect-free rate (over 70%) and has enough capacity to meet demand.

The percentage of VCMs used in smartphones increased from 62.4% in 2013 to 76.6% in 2016. The VCM market is dominated by Japanese and Korean companies, which have an aggregate 60%-70% market share. VCM can also be used in many other areas, such as VR/AR, drones and medical equipment.

The five largest single-cameras module providers are Sunny Optical, O-Film Tech [002456.SZ], Hon Hai Precision [2354.TT], Cowelle Holdings [1415.HK] and Samsung Electro-Mechanics, which have a market share of 8.9%, 8.7%. 5%, 4.7% and 4.5%, respectively. The dual-camera module market is dominated by three companies: LG, Sunny Optical and O-Film Tech, which have an approximate aggregate market share of 83%. We believe there is large potential for domestic dual-camera module manufacturers to grow since the dual-camera design is getting more and more popular, and the gross margin is of dual-cameras is about 2% higher than that of single-camera modules.
"

The major trends have been identified:

"From Single- to Dual-Camera: The dual-camera trend is now well-established in the smartphone industry, and dual-cameras can capture sharper images with more details than single-cameras can. Over 19 dual-camera equipped smartphones were released last year and 14 new dual-camera smartphones were introduced in the first four months of this year. The penetration rate of dual-cameras was only 5.6% in 2016, but it is expected to reach 15% this year, according to Sunrise Big Data. Generally, there four types of dual-cameras: a) Bayer + Mono (Huawei P9); b) wide + tele (iPhone 7 Plus); c) symmetrical (Huawei Honor 6 Plus); and d) asymmetrical (Xiaomi Redmi Pro).

At the current stage, 3D cameras on smartphones are used mostly in static conditions (e.g. facial recognition) and do not require a high frame rate, so structured light is the better choice for smartphone manufacturers. The cost of a structured light equipment is approximately US$20. The projector accounts about 50% of the total cost, or about US$10, algorithm chips cost US$4-$6, or 25%-30%, and receivers cost US$5-$6, or 20%-30%. Apple Inc. [AAPL.US] acquired PrimeSense, a 3D sensor company, for US$350m-$360m in 2013. PrimeSense is one of the major structured light players, and it provided research and related support for the development of Microsoft’s Kinect. As a result, we believe there is a strong possibility the new iPhone will use structured light, and Android smartphone companies will closely follow this trend. In Q4 2016, 432m smartphones were sold globally, of which 352m ran Android (81.7%) and 77m ran iOS (17.9%). We believe the increasing application of 3D sensing technology in Android smartphones will further boost the growth of the 3D camera industry.

360 degree fisheye panoramic camera: Huawei cooperated with Insta360 to announce the Honor VR 360-degree camera in February 2017, which allows users to take high-resolution 360-degree videos and photos. The VR camera has two 210-degree fisheye cameras, offering a seamless livestreaming experience. ProTruly [600074.CH], which is a lesser-known brand in China, presented the world’s first VR smartphone at Mobile World Congress 2017.
"

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ST FlightSense Presentation

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ST presentation at IoT World in May 2017 unveils a number of its future ToF products:

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ifm Demos ToF Backup Camera for Cars

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ifm publishes a demo video of O3D ToF camera advantages for cars, based on PMD 64 x 16 pixels sensor:

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e2v Sensors for Astronomy

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Teledyne e2v publishes two new presentations on image sensors for astronomy applications. "Teledyne e2v sensors for adaptive optics: wavefront sensing on ELTs - high rate, large format, and low noise" by Paul Jorden, D. Bourke, R. Cassidy, M. Fryer, P. Jerram, S. Moore, and J Pratlong:


Another presentation "e2v CMOS (and CCD) sensors (and systems) for astronomy" by Paul Jorden expands on NIR sensitive pixels:

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Cista Develops CIS on SMIC 130nm BSI Platform

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GlobeNewsWire: Cista Design is developing its next generation mobile sensors on SMIC 130nm BSI platform. Wilson Du, CEO and President of Cista System Corp. stated, “The low leakage SMIC process uses three aluminum metal layers for reduced cost and supports pixel sizes down to 1.4-micron for implementing our 8MP resolution CIS. We needed a reliable intellectual property vendor of OTP NVM for the SMIC 130nm BIS process node. We chose Kilopass because of its availability on the SMIC process and their reputation as a vendor with a breadth of offerings on the major foundries worldwide."

Possibly, Cista talks about C8390 sensor:

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TI and Melexis ToF Sensors with Softkinetic Pixel Inside

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Systemplus publishes reverse engineering reports of Melexis MLX75023 and TI OPT8241 ToF imagers, both based on Softkinetic pixel technology.

Melexis targets its sensors to automotive applications and its sensors has been already integrated in BMW in-car gesture recognition system:


TI chip, on the other hand, targets industrial applications:

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Ramp ADC Bug Video

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Deyan Levski, University of Oxford, UK, publishes a companion video to his IISW 2017 paper "A 12-bit Column-Parallel Flash TDC-Interpolated Ramp ADC with Online Digital Delay Element Correction" explaining a bug causing a larger than expected DNL in the ADC - quite a rare, possibly unique, video where an original designer explains his own bugs:

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IEEE Chip Hall of Fame: Kodak KAF-1300 CCD

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IEEE Spectrum publishes an article in Chip Hall of Fame series on 1991 1.3MP Kodak CCD KAF-1300 used in $25,000 DCS 100 camera:

At the time, 1 megapixel was a magic number,” says Eric Stevens, the chip’s lead designer. The chip—a true two-phase CCD—became the basis for future CCD sensors, helping to kick-start the digital photography revolution. What, by the way, was the very first photo made with the KAF-1300? “Uh,” says Stevens, “we just pointed the sensor at the wall of the laboratory.

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Nikon 8-15mm f3.5-4.5 fisheye review

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The Nikon 8-15mm f3.5-4.5E ED is the first Fisheye zoom for Nikon DSLRs, delivering a 180 degree field-of-view to both cropped and full-frame bodies, while also offering a full circular Fisheye image to full-frame. Find out how it performs in Thomas's in-depth review!…

The post Nikon 8-15mm f3.5-4.5 fisheye review appeared first on Cameralabs.

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Omnivision Proposes Curved Sensor Process

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Omnivision patent application US20170179189 "Curved Image Sensor" by Yuanwei Zheng, Gang Chen, Duli Mao, Dyson Tai, Arvind Kumar, Hung Chih Chang, and Chih-Wei Hsiung proposes using CMP dishing to make curved image sensors:

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How to photograph fireworks

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Firework displays can be spectacular but present a number of challenges to capture in-camera. In my simple guide I'll share my tips and techniques for photographing fireworks!…

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CEA-LETI Presents FF Curved Sensor Prototype

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CEA-LETI delivers a full-frame (24x32mm2) 20.4MP curved CMOS sensor prototype for astronomical applications:

"By directly correcting the field curvature in the focal plane, curved detectors help saving about one third of the optics, usually used as field flatteners, and then avoids undesirable distortion effect either in the image and also on the optical properties across the field of view.

After ten years of effort to convince the astronomical community about the benefits offered by curved focal planes, the activity is now ongoing around the world, with academic developments at ESO, Stanford, MIT, but also at the industrial level with recent realizations from Sony and Microsoft.
"

Soon to be off-the-shelf components for civil applications (cameras, bio-medical) these breakthrough components will blossom in the focal planes of any telescope in the future,” said Emmanuel Hugot from the Laboratoire d’Astrophysique de Marseille who leads the curved sensor program together with Bernard Delabre from the European Southern Observatory (ESO).

Fully functional prototype 20MP full frame (24x32mm²)
visible sensor by CEA-LETI

An Arxiv.org and OSA Optics Express paper talks about the telescope potential improvements with the curved image sensor.

Thanks to JG for the link!

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Yole on Consumer CIS Market

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Yole Developpement publishes few more bits from its oncoming report on CIS market:

"Looking more deeply into mobile phone applications, they are clearly dominating in revenue and volume. Smartphones are progressively evolving from having two cameras to having four. The rear and front camera are potentially being replaced by one to two dual cameras, and now also extra cameras for 3D sensing, face recognition and potentially for augmented reality applications. We will soon have as many image sensors as microphones in a mobile phone – but the value is much higher. The dual camera setup increased camera module value per smartphone toward $25 in 2016 and this will grow toward $30 in 2017."

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Canon PowerShot SX730 HS review

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The PowerShot SX730 HS is Canon's flagship pocket super-zoom. Like its predecessor, it packs 20 Megapixels and a 40x / 24-960mm zoom into a pocket body, now with a tilting screen and Bluetooth for easier connectivity and effortless GPS location tagging. Find out if it's for you or whether the Lumix TZ90 / ZS70 is a better buy in Ken's review!…

The post Canon PowerShot SX730 HS review appeared first on Cameralabs.

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LiDAR Spoofing Proposed and Tested

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The Register reports about KAIST paper on automotive LiDAR spoofing published at the International Association for Cryptologic Research's pre-print archive: "Illusion and Dazzle: Adversarial Optical Channel Exploits against Lidars for Automotive Applications" by Hocheol Shin, Dohyun Kim, Yujin Kwon, and Yongdae Kim.

"In this work, we have presented and experimentally verified two types of attacks that can severely degrade the reliability of lidars. Although we have listed many mitigative approaches in the discussion, they are either technically/economically infeasible or are not definitive solutions to the presented attacks. We do not advocate the complete abandonment of the transition toward autonomous driving, because we believe that its advantages can outweigh the disadvantages, if realistic adversarial scenarios are appropriately mitigated. However, such considerations are currently absent; therefore, automakers and device manufacturers need to start considering these future threats before too late."

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