Pixel shifting

Last updated

Pixel shifting refers to various technical methods, either to diminish damage to displays by preventing "burn in" of static images or to enhance resolution of displays, projectors, and digital imaging devices. The term is often used synonymously with the more specific term pixel shift.

Contents

Purposes

Avoid burn-in

See Pixel shifting avoids burn-in explained in detail for both analogue and digital screens.

Enhance character display resolution on terminals

Computer terminals such as the HP 2645A used a half-shift algorithm to move pixel positions by half a screen pixel in order to support the generation of multiple complex character sets. [1]

Increase projection resolution

Pixel shifting has been implemented in video projectors to expand the native 1080p resolution to produce an effectively 4K image on the screen. An exemplary implementation by the electronics corporation JVC is referred to as "e-shift". [2]

Increase capture and/or tonal resolution

Simple image (left) and pixel shifted image (right) with less noise and higher resolution (click to enlarge) COA Trogen Vergleich ENG Sony ILCE-7RM4.png
Simple image (left) and pixel shifted image (right) with less noise and higher resolution (click to enlarge)

Pixel shifting by movement of one or more sensors is a technique to increase resolution [3] and/or colour rendering [4] of image capturing devices.

The image at right displays the visible gain both in detail and in colour resolution produced by the Sony α7R IV 16-shot pixel shift mode, which results in a 240 Mpixel image, as compared to a single shot with the standard sensor resolution of 61 Mpixel. The crops taken from each image display the coat of arms at exactly the same size, albeit with different pixel counts.

One or more separate color channel sensors

Some camcorders and digital microscopes employ separate color channel sensors (usually RGB = red, green, blue) sensors.

  • Pixel shifting may be implemented for one or more of these sensors by moving such a sensor by a fraction of a pixel (or even a whole pixel value) in both x- and y-direction.[ citation needed ]
  • For example, early high-definition camcorders used a 3CCD sensor block of 960 × 540 pixels each. Shifting the red and blue sensors (but not the green sensor) by 0.5 pixel in both vertical and horizontal directions permitted the recovery of a 1920 × 1080 luminance signal.

One multi colour channel sensor

Currently most consumer imaging devices (cameras, camcorders, smartphones) employ a single multi colour channel sensor, on which the RGB (red, green, blue) pixels are usually arranged in a Bayer pattern. Thus any mode of pixel shifting movement either by fractional or by whole pixel values, whether to obtain a more detailed image or to improve tonal resolution, must necessarily engage the whole sensor.

  • More detailed information is to be obtained on page Pixel shift.

Other implementations

Related Research Articles

<span class="mw-page-title-main">RGB color model</span> Additive color model based on combining red, green, and blue

The RGB color model is an additive color model in which the red, green and blue primary colors of light are added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three additive primary colors, red, green, and blue.

<span class="mw-page-title-main">Digital camera</span> Camera that captures photographs or video in digital format

A digital camera is a camera that captures photographs in digital memory. Most cameras produced today are digital, largely replacing those that capture images on photographic film. Digital cameras are now widely incorporated into mobile devices like smartphones with the same or more capabilities and features of dedicated cameras. High-end, high-definition dedicated cameras are still commonly used by professionals and those who desire to take higher-quality photographs.

<span class="mw-page-title-main">Camcorder</span> Video camera with built-in video recorder

A camcorder is a self-contained portable electronic device with video and recording as its primary function. It is typically equipped with an articulating screen mounted on the left side, a belt to facilitate holding on the right side, hot-swappable battery facing towards the user, hot-swappable recording media, and an internally contained quiet optical zoom lens.

Liquid crystal on silicon is a miniaturized reflective active-matrix liquid-crystal display or "microdisplay" using a liquid crystal layer on top of a silicon backplane. It is also referred to as a spatial light modulator. LCoS was initially developed for projection televisions but is now used for wavelength selective switching, structured illumination, near-eye displays and optical pulse shaping. By way of comparison, some LCD projectors use transmissive LCD, allowing light to pass through the liquid crystal.

<span class="mw-page-title-main">Video projector</span> Device that projects video onto a surface

A video projector is an image projector that receives a video signal and projects the corresponding image on a projection screen using a lens system. Video projectors use a very bright ultra-high-performance lamp, Xenon arc lamp, LED or solid state blue, RB, RGB or remote fiber optic RGB lasers to provide the illumination required to project the image, and most modern ones can correct any curves, blurriness, and other inconsistencies through manual settings. If a blue laser is used, a phosphor wheel is used to turn blue light into white light, which is also the case with white LEDs. A wheel is used in order to prolong the lifespan of the phosphor, as it is degraded by the heat generated by the laser diode. Remote fiber optic RGB laser racks can be placed far away from the projector, and several racks can be housed in a single, central room. Each projector can use up to two racks, and several monochrome lasers are mounted on each rack, the light of which is mixed and transmitted to the projector booth using optical fibers. Projectors using RB lasers use a blue laser with a phosphor wheel in conjunction with a conventional solid state red laser.

<span class="mw-page-title-main">Autofocus</span> Optical system to focus on an automatically or manually selected point or area

An autofocus optical system uses a sensor, a control system and a motor to focus on an automatically or manually selected point or area. An electronic rangefinder has a display instead of the motor; the adjustment of the optical system has to be done manually until indication. Autofocus methods are distinguished as active, passive or hybrid types.

<span class="mw-page-title-main">HDV</span> Magnetic tape-based HD videocassette format for camcorders

HDV is a format for recording of high-definition video on DV cassette tape. The format was originally developed by JVC and supported by Sony, Canon, and Sharp. The four companies formed the HDV Consortium in September 2003.

<span class="mw-page-title-main">Digital single-lens reflex camera</span> Digital cameras combining the parts of a single-lens reflex camera and a digital camera back

A digital single-lens reflex camera is a digital camera that combines the optics and the mechanisms of a single-lens reflex camera with a digital imaging sensor.

<span class="mw-page-title-main">Digital photography</span> Photography with a digital camera

Digital photography uses cameras containing arrays of electronic photodetectors interfaced to an analog-to-digital converter (ADC) to produce images focused by a lens, as opposed to an exposure on photographic film. The digitized image is stored as a computer file ready for further digital processing, viewing, electronic publishing, or digital printing. It is a form of digital imaging based on gathering visible light.

<span class="mw-page-title-main">Image stabilization</span> Techniques used to reduce blurring of images

Image stabilization (IS) is a family of techniques that reduce blurring associated with the motion of a camera or other imaging device during exposure.

<span class="mw-page-title-main">Sony camcorders</span>

Sony Corporation produces professional, consumer, and prosumer camcorders such as studio and broadcast, digital cinema cameras, camcorders, pan-tilt-zoom and remote cameras.

<span class="mw-page-title-main">Image processor</span> Specialized digital signal processor used for image processing

An image processor, also known as an image processing engine, image processing unit (IPU), or image signal processor (ISP), is a type of media processor or specialized digital signal processor (DSP) used for image processing, in digital cameras or other devices. Image processors often employ parallel computing even with SIMD or MIMD technologies to increase speed and efficiency. The digital image processing engine can perform a range of tasks. To increase the system integration on embedded devices, often it is a system on a chip with multi-core processor architecture.

Document cameras, also known as visual presenters, visualizers, digital overheads, or docucams, are real-time image capture devices for displaying an object to a large audience. Like an opaque projector, a document camera is able to magnify and project the images of actual, three-dimensional objects, as well as transparencies. They are, in essence, high resolution web cams, mounted on arms so as to facilitate their placement over a page. This allows a teacher, lecturer or presenter to write on a sheet of paper or to display a two or three-dimensional object while the audience watches. Theoretically, all objects can be displayed by a document camera. Most objects are simply placed under the camera. The camera takes the picture which in turn produces a live picture using a projector or monitor. Different types of document camera/visualizer allow great flexibility in terms of placement of objects. Larger objects, for example, can simply be placed in front of the camera and the camera rotated as necessary, or a ceiling mounted document camera can also be used to allow a larger working area to be used.

<span class="mw-page-title-main">4K resolution</span> Video or display resolutions with a width of around 4,000 pixels

4K resolution refers to a horizontal display resolution of approximately 4,000 pixels. Digital television and digital cinematography commonly use several different 4K resolutions. In television and consumer media, 3840 × 2160 is the dominant 4K standard, whereas the movie projection industry uses 4096 × 2160.

A 3D camcorder can record 3D video.

The Pentax Q series is a series of mirrorless interchangeable-lens cameras made by Pentax and introduced in 2011 with the initial model Pentax Q. As of September 2012, it was the world's smallest, lightest interchangeable lens digital camera. The first models used a 1/2.3" back-illuminated sensor CMOS image sensor. The Q7, introduced in June 2013, uses a larger 1/1.7" type sensor. The Q system is now discontinued.

<span class="mw-page-title-main">Pixel shift</span>

Pixel shift is a method in digital cameras for producing a super resolution image. The method works by taking several images, after each such capture moving ("shifting") the sensor to a new position. In digital colour cameras that employ pixel shift, this avoids a major limitation inherent in using Bayer pattern for obtaining colour, and instead produces an image with increased colour resolution and, assuming a static subject or additional computational steps, an image free of colour moiré. Taking this idea further, sub-pixel shifting may increase the resolution of the final image beyond that suggested by the specified resolution of the image sensor.

<span class="mw-page-title-main">Pentax K-3 II</span> Digital camera model

The Pentax K-3 II was a flagship APS-C DSLR camera announced by Ricoh on April 23, 2015.

References

  1. https://drive.google.com/file/d/1UYKj935C3sHSh1RuvRtPPtO3h_VZbgeL/view 2640 Character Set Generation
  2. "D-ILA Projectors DLA-X900R / DLA-X700R / DLA-X500R: product page of manufacturer, chapter 'New e-shift 3 Technology'". JVC . Retrieved 2021-11-04.
  3. "Can Pixel Shift Compete with a Bigger, Higher Resolution Sensor?". PetaPixel . Retrieved 2021-11-05.
  4. "Pixel Shift Resolution Photos Explained". ephotozine . Retrieved 2021-11-05.
  5. "Pentax K-3 II Review - Pixel Shift Resolution mode". Imaging-Resource.com. Retrieved 2021-11-05.