Canon Super-35mm Cinema Sensor Explained

Canon published few whitepapers talking about design considerations of its Super-35mm sized CMOS sensor for recently announced EOS C300 video camera. The first one "New 35mm CMOS Image Sensor for Digital Cine Motion Imaging" gives the sensor spec:


The color filter array is the classic Bayer. Canon explains the resolution choice:

Illustrating the separate CFA array and the CMOS imager while also
showing the CFA separated into its component color filters to better expose
the structure of their respective sparsely sampled lattices

"The image sensor readout strategy radically departs from the customary “De-Bayer” deployment of quincunx sampling of the green photosites to maximize the green video resolution (and hence the matriced Luma resolution). The design strategy of this new sensor is to not to seek any form of “4K” resolution — but rather to specifically confine the reconstruction of each of the R,G, and B video components to a full digital sampling structure of 1920 (H) x 1080 (V) — according to the SMPTE 274M HDTV Production Standard."

Showing the concept of structuring the final Green video component within the
pre-processing LSI from the two dual video readouts from the CMOS image sensor

"The dual Green process offers the following significant technical advantages:

  1. Doubles the effective saturation level of the summed Green output video
  2. Increases the noise of the final Green output only by a factor of square root of two
  3. Combination of 1) and 2) increases the effective dynamic range of the green signal — and as a consequence, that of the matriced Luma signal
  4. Increases the effective output green video bit depth
  5. The half-pixel offset between the two separate green sampling lattices — both horizontally and vertically — virtually eliminates the first order sideband spectra associated with the sensor sampling process. This eliminates green aliasing.
  6. Creates an effective FIR* filter within the readout process that aids the optimization of the horizontal MTF and the progressive vertical MTF and associated aliasing."
The summation of two greens is said to increase the DR from 70dB to 73.5dB in green (in fact, from 70.5 to 73.5) or to 72dB in luma (12 stops).

Although the camera frame rate is 24p fps, the readout speed is 1/60s to reduce rolling shutter effects:


In 60i mode each half-frame is read at 1/120s - same per-row speed as in 24p mode.

The low read noise is achieved by limiting the readout amplifier bandwidth, as shown below:


Another Canon whitepaper "RGB Resolution Considerations in a New CMOS Sensor for Cine Motion Imaging" shows advantages of the proposed green processing in resolution extension:

Showing the two separate green 1920 (H) x 1080 (V) photosite lattices
and the horizontal and vertical timing offsets between each of the
two “diagonal” pixels that are summed during the readout process

The resulting horizontal and vertical MTFs of the whole system are improved:


The summary says: "A new CMOS image sensor has been described. It represents a definitive decision by Canon to enter the global field of digital cinematic motion imaging. It is anticipated that there will be many progressive advances in the years ahead. Accordingly, a priority was assigned to taking a first step into this important field of imaging by placing an initial focus on originating a very high quality RGB video component set specifically intended for high-performance High definition video production."

Another whitepaper is titled "Sensitometric Characteristics of EOS C300 Digital Cine Camera" and mainly focused on system processing of the video signal, introduces "Canon-Log" response.

Samsung IEDM 2011 Paper

Eric Fossum put his Samsung IEDM 2011 paper on-line:

"A 192×108 pixel ToF-3D image sensor with single-tap concentric-gate demodulation pixels in 0.13 μm technology"
T.Y. Lee, Y.J. Lee, D.K. Min, S.H. Lee, W.H. Kim, S.H. Kim, J.K. Jung, I. Ovsiannikov,
Y.G. Jin, Y.D. Park, E.R. Fossum, and C.H. Chung

"A 3D-ToF FSI image sensor using novel concentric photogate [CG] pixels with single-tap operation is described. Through the use of CG structure, we are able to achieve high DC at larger pixel pitches. The new CG pixel structure substantially improves DC [demodulation contrast] to 53% at 20MHz at 28 μm pixel pitch. Recent initial results from a backside-illuminated (BSI) implementation of the same sensor show further improved performance and will be reported elsewhere."

Truesense Imaging Inc. and Digital Optics Corp.

As written in comments, the recently acquired Kodak Image Sensor Solutions has been quietly renamed to Truesense Imaging, Inc. Kodak has first used Truesense name for its W-RGB color filter products almost 3 years ago. I wonder if the new company name meant to emphasize the W-RGB products importance.

Meanwhile, Tessera renamed its imaging and optics division into Digital Optics Corporation. The new entity is responsible for wafer-scale optics (former Shellcase), EDoF (former Eyesquad and Dblur), MEMS AF motors (former Siimpel), micro-optics (the original bearer of Digital Optics Corporation name, acquired by Tessera in 2006) and image enhancement software (former Fotonation). It appears that the division has been renamed and separated into the wholly owned subsidiary in June 2011.

Another part of Tessera dealing with chip packaging is separated and renamed too. Its new name is Invensas. In Nov. 2011 Invensas acquired patent assets of California-based TSV foundry ALLVIA. It does not seem to target image sensor applications though.