Patent: Quad Pixel AF and a Hybrd DSLR

[Canon Rumors]

Now this is a pretty interesting patent <a href="https://www.canonnews.com/canon-patent-application-that-illustrates-a-hybrid-dslr-and-quad-pixel-af-sensors">uncovered by Canon News</a>. who calls it “an intense patent”, and understanding all of the nuances of it is quite difficult.</p>
<p>Firstly, the patent deals with multiple parallax images for computational photography, and it clearly shows Quad Pixel AF sensors and the problems that 4 composite images have on the final image.</p>
<p>Secondly, the example diagram clearly shows a DSLR with an EVF.</p>
<p>Canon News has previously uncovered 3 other patents that mention Quad Pixel AF, you can see them <a href="https://www.canonnews.com/another-quad-pixel-af-sensor-patent-application">here</a>, <a href="https://www.canonnews.com/another-quad-pixel-af-sensor-patent-application">here</a> and <a href="https://www.canonnews.com/another-quad-pixel-af-sensor-patent-application">here</a>.</p>
<p> </p>
<span id="pty_trigger"></span>

 

[Chaitanya]

Unlike Nikon F, Pentax K or Sony/Minolta A , Canon's EF mount is already a full electronic mount so they can get away with removing the mirror box assembly and make a MILC on EF mount. So not sure why Canon is filing patent for Optical/Electronic hybrid viewfinder.

 

[BasXcanon]

The market is saturated with small FF ILC from Sony and Leica.
It has costed Canon 30 years to build up the current state of EF lenses empire.
Of which roughly 5 are absolute better than anything else any mfg has put on the market.
Next to that there are about 10 native Canon lenses that are great value for money and f*ing cheap to get compared to the competition. If you need 35mm T/S lenses, Canon is way too go. If you need anything above 200mm, Canon and Nikon are for you. But compared to some German glass, Canon just is not there.

I have no clue what a new mirrorless line from Canon is going to offer and change worlds in a small period of time.
In my eyes they are way better of offering 1 SLT with EVF and forget the FF MILC's.
Just give us a bit of salt and pepper in the EFM APS-C cameras and come with a G1Xm3 style camera with FF sensor and 45mm prime lens.
Even if Canon/Nikon/Sony/Pnetax comes out with a new camera mount including 50 new lenses within 3 years, I just don't want to spend time searching for which ones are any good and which ones are the rotten tomatoes.

 

[CafferyPhoto]

It definitely has an EVF which comes straight from the video signal processing circuit whereas the main display aparatus comes from the microcomputer? EVF should be blazing fast if it doesn't have to be processed.

Zoom driving circuit?? Is this for a video camera?

 

[Tugela]

It has nothing to do with hybrid viewfinders or quad pixel detectors, various embodiments of different types of technologies are just included as examples of how the invention could be used. The block diagram encompasses them all, that does not mean that an actual camera would include everything so depicted.

The application deals with claims about using multiple images that record things such as parallax information, that can then be processed later to produce an image. Basically a light field camera. That is all.

 

[Don Haines]

and this is probably what a Canon FF mirrorless will present to the world....

 

[nchoh]

Now this is a pretty interesting patent <a href="https://www.canonnews.com/canon-patent-application-that-illustrates-a-hybrid-dslr-and-quad-pixel-af-sensors">uncovered by Canon News</a>. who calls it “an intense patent”, and understanding all of the nuances of it is quite difficult.</p>
<p>Firstly, the patent deals with multiple parallax images for computational photography, and it clearly shows Quad Pixel AF sensors and the problems that 4 composite images have on the final image.</p>
<p>Secondly, the example diagram clearly shows a DSLR with an EVF.</p>
<p>Canon News has previously uncovered 3 other patents that mention Quad Pixel AF, you can see them <a href="https://www.canonnews.com/another-quad-pixel-af-sensor-patent-application">here</a>, <a href="https://www.canonnews.com/another-quad-pixel-af-sensor-patent-application">here</a> and <a href="https://www.canonnews.com/another-quad-pixel-af-sensor-patent-application">here</a>.</p>
<p> </p>
<span id="pty_trigger"></span>

When I first saw the illustrations with the quad pixels, I thought cool. Then on second thought,... why would one need quad pixels? One only needs dual pixel to determine focus.

So I read the article in the link (not completely) until I found out what the patent is about...

Quad pixels are used for light field photography. The patent is about how to compress and store both a conventional image as well as the light field information into a reasonably sized file.

Light field photography that works? How soon?

 

[Tugela]

It definitely has an EVF which comes straight from the video signal processing circuit whereas the main display aparatus comes from the microcomputer? EVF should be blazing fast if it doesn't have to be processed.

Zoom driving circuit?? Is this for a video camera?

Ummm...that is how everyone else does EVFs as well, so nothing new there, nor does it have any impication for EVF responsiveness.

All those extra circuits are there to serve as an example. In order to get a patent you not only have to simply make a claim, you also have to teach how it could be used and provide examples. The block diagram serves that purpose in that it collectively shows how various technologies might be used in a camera in tandem with what is actually being claimed (which is methods of gathering and combining data from multiple images).

 

[Mt Spokane Photography]

Its entirely possible but not likely that this is the camera we will see this fall at photokina, or maybe a demo/development teaser. I did not read every word in the patent, but skimmed thru several pages reading to determine exactly what they were doing.

As previously mentioned, its a light field camera, but it is unique in that it takes advantage of photo sensors that are divided into 2, 4, or even many more portions to form the light field image. Thus, the apparent focus area can be moved according to the combination of sub pixel images selected.

It is very complicated with several optional ways to get at the same end result.

The problem with conventional light field cameras comes with the huge file size and enormous processing difficulty. The patent gets around the obstacle by creating a smaller sized image from each of the multiple pixels and combining them as needed to alter the point of focus.

Its a nice way to get around the issue of processing a light field camera image, but the point of focus from the sub pixels in a 5D MK IV only changes a fraction of a inch.

The final light field image must still be created by a external computer, which makes sense, since the photographer would want to move the point of focus to suit his needs.

From the 20th page, this paragraph is the hint as to the purpose of the patent. I used OCR to convert it to text, so it may come out a bit distorted.

BACKGROUND ART
[0002] There are known to be image capture apparatuses
in which an exit pupil of a shooting lens (imaging optical
system) is divided into multiple pupil regions, and according
to which multiple images that each correspond to one pupil
region can be generated with one shooting operation (U.S.
Pat. No. 4,410,804). These multiple images are images with
parallax (parallax images), and therefore are pieces of information
representing not only the spatial distribution but also
the angular distribution of the light intensity, and have
properties similar to data known as light field (LF) data and
light space data.
[0003] Ren Ng et al, "Light Field Photography with a
Hand-Held Plenoptic Camera", Stanford Tech Report CTSR
2005 February , 2005 Apr. 20) discloses a refocus technique
in which the in-focus position of the captured image is
changed after shooting by using LF data to combine images
in an imaging plane (virtual imaging plane) different from
that at the time of shooting.

 

[crashpc]

I wonder why they just don't use whole pixels for AF/LF too....

 

[Mt Spokane Photography]

I wonder why they just don't use whole pixels for AF/LF too....

Sony uses whole pixels for AF, but they can't be part of the image, Canon managed to get around that issue with the dual pixel setup.

You only get a image that is a fraction of the total pixels when used for light field. The Lytro had a 40mp sensor to get a 4 mp image. By using dual, quad, or even a pixel divided into 8 sub pixels, you do not need a 240 mp sensor to get a 30 mp image. The Lytro images originally had to be sent to lytro to be processed by a powerful computer in order to get a finished image. The processing power to get a 30 mp image would have been fantastic. I think that Canon's patent gets around it to a great extent, but not entirely.

Although examples show a dual and quad pixel setup, the patent actually applies to any number of sub pixels, so it depends on the ability to manufacture them, and on the computing power needed to process them.

 

[jolyonralph]

The Lytro had a 40mp sensor to get a 4 mp image.

Almost right. The Lytro had a 40mpx sensor to get an 0.4 megapixel image! - see http://www.everyothershot.com/lytro-illum/

 

[Antono Refa]

Secondly, the example diagram clearly shows a DSLR with an EVF.

It also shows a mirror and a pentaprism.

 

[jolyonralph]

Secondly, the example diagram clearly shows a DSLR with an EVF.

It also shows a mirror and a pentaprism.

The 'EVF driving circuit' is linked to a totally different part of the architecture than the 'Display Driving circuit' which drives "main display apparatus" and "auxiliary display apparatus".

Now, for all sensible purposes the rear screen displays identical content to the EVF, so an "EVF" as we normally know it would be covered under the "auxiliary display apparatus" side of things.

So this means something else. Could it simply mean the LCD display within the viewfinder? I'm pretty sure someone drafting a patent for Canon would know the difference.

More likely it's Canon covering the options, with their engineers knowing that an implementation of this sort of technology could work with the EVF driven either directly by the microcomputer or by the video signal processing circuit, therefore they've covered both within the patent just in case.

 

[Richard CN]

Secondly, the example diagram clearly shows a DSLR with an EVF.

It also shows a mirror and a pentaprism.

The 'EVF driving circuit' is linked to a totally different part of the architecture than the 'Display Driving circuit' which drives "main display apparatus" and "auxiliary display apparatus".

Now, for all sensible purposes the rear screen displays identical content to the EVF, so an "EVF" as we normally know it would be covered under the "auxiliary display apparatus" side of things.

So this means something else. Could it simply mean the LCD display within the viewfinder? I'm pretty sure someone drafting a patent for Canon would know the difference.

More likely it's Canon covering the options, with their engineers knowing that an implementation of this sort of technology could work with the EVF driven either directly by the microcomputer or by the video signal processing circuit, therefore they've covered both within the patent just in case.

kind of. keep in mind that there's different refresh rates for the EVF,etc so they may want to drive it differently.

however there's at least two different Displays which i took as LCD,EVF and Optical described.

where embodiment usually cover off the variations of design, they usually don't add in fluff into the design such as this unless there is a good reason.

 

[maxfactor9933]

It definitely has an EVF which comes straight from the video signal processing circuit whereas the main display aparatus comes from the microcomputer? EVF should be blazing fast if it doesn't have to be processed.

Zoom driving circuit?? Is this for a video camera?

I m pretty sure canon not gonna change the mount for its coming FFML. there is absolutely no reason to change the mount. they can keep the flange distance. if you look at sony lenses, you will that every single lens is sort of welded to a adapter to compensate the flange distance. (even GM lenses). so I rather to carry one spacer on my camera than carry few welded to every single lens. literally save weight and space