User talk:Epzcaw/sandbox
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Maybe this is the better place to further discuss the text.
I originally thought your new definition was fine, but your remark on how electronic holographic projection would work made me think again. Don't most holographic displays do this already? In addition to that, I also noted the article's section about non-optical holography.
I would now say that Holography is the encoding of a three-dimensional wavefront, for instance of [or "as"?] the light field of a three-dimensional image [or "view" or "object"?].
You seem to doubt the element of encoding is actually there if it would be generated by an electronically controlled array of lasers, but I suppose this would still entice the conversion of physical data into an electronic stream, at least for recorded or programmed variations. Even for a randomly generated light field there would be a specific code/pattern for every instance/form, which could be read from (registered by) the electronic equipment (which probably would involve some digital components, and, by definition, would be encoded). I'm quite sure the result would be called a hologram, and not just because so many people are confused about the technology. Any reason not to call it a hologram, would most likely be that it isn't done with the traditional techniques that have always been called holography (which I gather have always involved encoding the interference of diffraction as a pattern into a physical structure). Such a reason would basically be similar to still defining holography as a type of 3D photography or a recording.
I think the part for instance, to produce optical elements such as lenses is rather unspecific; surely lenses and optical elements are still widely produced in very different ways, and it's hard for people without the specific knowledge to imagine how it's done. Especially the example of lenses is confusing to me; it makes me think about all the other optical diffraction stuff without interference or lasers that I probably know too little about. The checkout scanners seemed to be an understandable example, at least for me.
Maybe it's best to soon after the definition describe how the technology originated as the photographic recording of the interference pattern of a light field of a physical object and a reference beam of the light source (should diffraction be in here to?), but has also led to computer-generated holography and holographic optical scanning devices (and more?).Joortje1 (talk) 12:17, 16 August 2020 (UTC)
- Epzcaw, Thanks for taking the time to improve this article - it needs it, and I've been trying to avoid getting dragged into it myself precisely because I appreciate it's a mammoth task:( Starting with the first paragraph, I'm afraid I think the CD-audio analogy is really unhelpful in practice. My stab at the opening is along the lines of:
- "A hologram is a diffractive record of an interference pattern from which it is possible to reproduce the original light field, resulting in an image which retains the depth and parallax of the original scene. Holography is the science and practice of making holograms."
- For me, the rest of the proposed Introduction is generally OK. I'd say a hologram consists of a very fine diffraction grating rather than speckle pattern, and remove "(probably not a live one!)" re. the mouse as both speculative and not scholarly in tone. Since there isn't a History section in the main article, I suggest adding a final paragraph to the introduction: "Holography was first described by Dennis Gabor in 1948, for which he was awarded the Nobel Prize for Physics in 1971".
- Joortje1, I find your comments difficult to understand. For example in "You seem to doubt the element of encoding is actually there if it would be generated by an electronically controlled array of lasers," above, what does "it" refer to? The essence of holography is that the phase of the light is recorded, hence the need for a reference beam (even virtually inside a computer). Simplistically: No phase measurement, not holography! Louis Knee (talk) 17:21, 28 August 2020 (UTC)
- Louis Knee, luckily Epzcaw seemed to understand most of what I tried to convey, at least in earlier conversations. My main problem with the curent version and most drafts is the idea that holography can only be recorded from an existing scene, while nowadays an imaginary scene can be programmed. It seems like new holographic display techniques are quite commonly presented with programmed imagery. Whatever your concept of "phase" means, I suppose that this "phase" and its reference beam can be made up to create a hologram. That's why I suggested to replace references to "recording" with "encoding". Similarly, "reconstructing" should probably be replaced with "decoding", since a programmed image previously only existed in the code and in someone's mind. Is there any reason that a programmed holographic image of an imaginary scene should not be called a hologram? If not, how would you record or measure its phase?Joortje1 (talk) 08:42, 21 September 2020 (UTC)
- "Is there any reason that a programmed holographic image of an imaginary scene should not be called a hologram?" No - that's exactly what a computer-generated hologram is. "If not, how would you record or measure its phase?" Um, the phase is calculated by the software. The hologram can then recorded on to a glass plate or whatever, and is then replayed in identical fashion to a hologram of a physical scene. If the replay process is identical, then the word "reconstructed" applies to both forms. Can you provide a reference to this usage of "decoded", please? --Louis Knee (talk) —Preceding undated comment added 21:20, 24 September 2020 (UTC)
- Louis Knee, luckily Epzcaw seemed to understand most of what I tried to convey, at least in earlier conversations. My main problem with the curent version and most drafts is the idea that holography can only be recorded from an existing scene, while nowadays an imaginary scene can be programmed. It seems like new holographic display techniques are quite commonly presented with programmed imagery. Whatever your concept of "phase" means, I suppose that this "phase" and its reference beam can be made up to create a hologram. That's why I suggested to replace references to "recording" with "encoding". Similarly, "reconstructing" should probably be replaced with "decoding", since a programmed image previously only existed in the code and in someone's mind. Is there any reason that a programmed holographic image of an imaginary scene should not be called a hologram? If not, how would you record or measure its phase?Joortje1 (talk) 08:42, 21 September 2020 (UTC)
- Epzcaw, I've had a quick look at your new version. I thought the second paragraph felt clunky, especially from repetition of "light fields". My attempt at an improved version is below, but still feels awkward - too many "patterns". It's quite hard to squish everything into a single concise paragraph! I'll try to find time for another go at the weekend. (Also some tweaks in para. 4). Not sure of the best way forward - I didn't want to edit your sandbox so I've added my version as a new section below, but that does make it hard to see the changes made. I've no idea why I thought there was no History section in the main article, but I'd leave that final line in the intro anyway: it means the History section can be moved elsewhere in the article if needed, and the Nobel prize reference bolsters (indirectly) the definition of holography. --[[User:Louis
Knee|Louis Knee]] (talk) 21:19, 15 September 2020 (UTC)
- I've deleted my version in the sandbox and moved yours there. My only issue is the first sentence.
- Most people will not know what a "diffractive recording" is and I feel that the introduction should be understandable by all, or nearly all readers. How about
- Holography is a technique by which a light field can be recorded and subsequently reconstructed in the absence of the original light field. The reconstructed image retains the depth and parallax of the original scene.
- Epzcaw (talk) 08:26, 17 September 2020 (UTC)
- Most people will not know what a "diffractive recording" is and I feel that the introduction should be understandable by all, or nearly all readers. How about
- I'm afraid I haven't yet been able to find the time to look at this properly. Some comments to give an idea of how I'm approaching this:
- hovering the mouse over a wikipedia internal link brings up the start of the article as a pop-up, so the opening sentence should be as complete a definition as possible
- according to context "hologram" can refer either to the perceived image or to the artefact storing it. "Recording" shares this ambiguity. (NB we need to add a sentence on this later in the introduction!)
- anything that looks like defining a hologram as a "3D image" or "projection" needs to be avoided, as it will be misinterpreted to include cheap stage effects (para. 6)
- "diffractive" should be a link to https://en.wikipedia.org/wiki/Diffraction
- general readers will not be familiar with wave-fronts, BUT then I'm not sure "light-field" is a well defined term
- Having said that, I'm not sure I'd know what a "diffractive recording" is and I came up with the phrase! Looks like something from '80s sci-fi :( You're probably on the right track in changing from "hologram" to "holography" as the core word. This is my slightly pruned version of your opening line:
- Holography is a technique by which a light field is recorded and subsequently reconstructed in the absence of the original. The reconstructed image retains the depth and parallax of the original scene.
- My quibble is that this is more about what holography can do, rather than how it does it. I'd still prefer a reference to interference or diffraction in there somewhere. Hope this helps. I'll still try to have another look at this in the next few days. Appreciate your efforts! --Louis Knee (talk) 09:39, 20 September 2020 (UTC)
- I think I understand this fear of defining a hologram as a 3D image. Imho, the section Holography#Non-optical provides a much stronger argument to avoid such a definition. Hence my suggestion to use "the light field of a three-dimensional image/view/object" as an example of a holographically created wavefront. However, there is a reason why many encyclopedias and dictionaries refer to holograms as 3D images. I suppose even an acoustic hologram can be regarded as an image containing three-dimensional data (maybe "pattern" would be a better word instead of "image", but still). More importantly, the most common interpretation and use of the concept "holography" involves 3D imagery. That doesn't mean 3D imagery should be called holography and it's a pity people are confused by Pepper's ghost and other techniques that are often misidentified. Holography in fiction often seems to perfectly fit both the scientific and popular ideas, as for instance with The Doctor (Star Trek: Voyager). If you aks me, the current wikipedia definition is way too rigid, a bit too technical (with too little explanation or bluelinking of uncommon terminology) and just not entirely correct.Joortje1 (talk) 08:42, 21 September 2020 (UTC)
- I'm afraid I haven't yet been able to find the time to look at this properly. Some comments to give an idea of how I'm approaching this:
- Can anyone point out any problems in my proposed definition, please? I would now formulate as Holography is the encoding and decoding of a three-dimensional wavefront, for instance that of the light field of a three-dimensional view.Joortje1 (talk) 08:42, 21 September 2020 (UTC)
- My objection is the same as to Epzcaw's above; that by concentrating on what holography does, you fail to define what it is. "...encodes a three-dimensional wavefront" applies just as much to a Shack-Hartmann device, which isn't holography. In addition, how does a "view" emit a "light field"? --Louis Knee (talk) 22:41, 23 September 2020 (UTC)
- Is "interference pattern" a better term in a definition of holography, or "wave front" or something else?Joortje1 (talk) 08:42, 21 September 2020 (UTC)
- Again, I have no idea what you mean. Is it "Is "interference pattern" a better term when defining "holography" or defining "wave front", or defining something else?" or is it "Is "interference pattern" or "wave front" the better term in a definition of holography?" An interference pattern and a wavefront are different things. --Louis Knee (talk) 22:41, 23 September 2020 (UTC)
- I'm sorry. English is not my native language, so I may sometimes fail to grasp certain nuances in my writings. In this case it wasn't as much about which word to choose, but which of the previous mentioned subjects that apparently could be encoded as a hologram (interference pattern or wavefront) would best define holography in a sentence like the one in my proposed definition above. I understand how this question wasn't very clear.Joortje1 (talk) 06:40, 24 September 2020 (UTC)
- Epzcaw's proposed overhaul seems to have been motivated by my argument that the wikipedia definition excluded computer-generated holography. More recent changes in the actual article even made things worse: holography now apparently is a "real world recording". Most suggestions on this sandbox talk page still seem to subscribe to that idea. Why?Joortje1 (talk) 08:42, 21 September 2020 (UTC)
- I'm not quite sure what you mean by a "real-world device". I believe that a hologram must be a real physical object in order to generate a real physical wavefront. Epzcaw (talk) 19:28, 21 September 2020 (UTC)
- Epzcaw, I agree with this - the outcome of CGH must be a physical artefact in order to reconstruct the image (by diffraction), and digital holography likewise requires a physical device to capture the input pattern. (That doesn't mean we must include the term "physical" in any definition). --Louis Knee (talk) 21:46, 24 September 2020 (UTC)
- I'm not quite sure what you mean by a "real-world device". I believe that a hologram must be a real physical object in order to generate a real physical wavefront. Epzcaw (talk) 19:28, 21 September 2020 (UTC)
- The current version of the article (not your sandbox version) calls a hologram a "real world recording" (not my words, not "device"). Such a definition excludes computer-generated holography and in my opinion is worse than the previous "physical recording".
- Have you considered that the intention of "real-world" may have been to distinguish our actual world from fiction (e.g Star Wars), rather than the physical from the virtual (computer-generated)? Writing correct, clear, unambiguous text is hard. You've both made a number of points and it will take me a while to chew through them. :( --Louis Knee (talk) 22:41, 23 September 2020 (UTC)
- The current version of the article (not your sandbox version) calls a hologram a "real world recording" (not my words, not "device"). Such a definition excludes computer-generated holography and in my opinion is worse than the previous "physical recording".
- In the technical meaning of the encoded pattern, a hologram can arguably only be a physical object, although in many a holographic display it's probably an electronically generated pattern that is not as tangible as suggested by "a real physical object". In the very common meaning of the decoded image of a holographic pattern (which the term "hologram" very commonly refers to), a hologram must presumably have a wavefront that is as physical as a real-world holographic recording, but if it's a computer-generated hologram it may better be referred to as an "artificial physical wavefront". I'm sorry if these ideas confuse the definitions and concepts of holography that people were used to, but I thought you agreed when I proposed on the article's talk page that the wikipidia definition should also take cg holography into account.Joortje1 (talk) 05:15, 22 September 2020 (UTC)
- "in many a holographic display it's probably an electronically generated pattern that is not as tangible..." No, the pattern is equally as tangible, to diffract the light to reconstruct the image. Or are you claiming that artefacts created by 3-d printing are somehow not real because they started off as digital files??? --Louis Knee (talk) 21:46, 24 September 2020 (UTC)
- How is a pattern in electro-holography tangible and what does it have to do with 3d printing? Sure, even after the imagery has been designed and computed, there is still physical hardware involved to generate the pattern. What do you believe this hardware does? Print the pattern?Joortje1 (talk) 05:04, 25 September 2020 (UTC)
- "How is a pattern in electro-holography tangible" - by the act of diffracting a physical, actual replay beam of light. "what does it have to do with 3d printing?" 3-d printing is for comparison, to make you think about your proposed words: 3-d printers also "are quite commonly presented with programmed imagery. .... That's why I suggested to replace references to "recording" with "encoding". Similarly, "reconstructing" should probably be replaced with "decoding", since a programmed image previously only existed in the code and in someone's mind." so presumably you would demand that 3-d printers "decode" CAD drawings into plastic? "What do you believe this hardware does? Print the pattern?" Yes - literally for display CGH work. When I saw Martin Richardson's arty-farty CGH stuff in Bracknell a (long) while back, it was definitely on plates on the gallery walls. That's why holographic printers were a thing, e.g. the Zebra Imaging one mentioned on page 8 here. Obviously if you want to modify the hologram at video rate then the technology will be different (page 12), but there still has to be a physical manifestation of the fringe pattern to diffract the light - and this is a specialised sub-topic, probably for holographic display, rather than something that needs thrashing out in the introductory paragraph of the general article. "I'm sorry if these ideas confuse the definitions and concepts of holography that people were used to..." But Wikipedia is not here to invent novel interpretations - "Wikipedia editors must base their contributions on reliable, published sources." Wikipedia:No_original_research --Louis Knee (talk) 23:12, 26 September 2020 (UTC)
- How is a pattern in electro-holography tangible and what does it have to do with 3d printing? Sure, even after the imagery has been designed and computed, there is still physical hardware involved to generate the pattern. What do you believe this hardware does? Print the pattern?Joortje1 (talk) 05:04, 25 September 2020 (UTC)
- "in many a holographic display it's probably an electronically generated pattern that is not as tangible..." No, the pattern is equally as tangible, to diffract the light to reconstruct the image. Or are you claiming that artefacts created by 3-d printing are somehow not real because they started off as digital files??? --Louis Knee (talk) 21:46, 24 September 2020 (UTC)
- In the technical meaning of the encoded pattern, a hologram can arguably only be a physical object, although in many a holographic display it's probably an electronically generated pattern that is not as tangible as suggested by "a real physical object". In the very common meaning of the decoded image of a holographic pattern (which the term "hologram" very commonly refers to), a hologram must presumably have a wavefront that is as physical as a real-world holographic recording, but if it's a computer-generated hologram it may better be referred to as an "artificial physical wavefront". I'm sorry if these ideas confuse the definitions and concepts of holography that people were used to, but I thought you agreed when I proposed on the article's talk page that the wikipidia definition should also take cg holography into account.Joortje1 (talk) 05:15, 22 September 2020 (UTC)
- I think we were almost there when you proposed: "Holography is the encoding of a light field as an interference pattern. It is commonly used as a 3D imaging technique, but the principle is also widely applied in different ways." Maybe it should include non-optical holography and be "Holography is the encoding of a wave interference pattern"? And then something like: "It is commonly used as a 3D imaging technique that diffracts light bouncing off an encoded pattern on a 2D surface to produce the light field of an object or scene, but the principle is also widely applied in different ways."Joortje1 (talk) 06:05, 22 September 2020 (UTC)
- I can envisage a device which generates a light field which has been generated by a computer - perhaps an array of very small lasers each of which is driven with the appropriate amplitude and phase so that when viewed by a camera or an eye, an image is formed of the scene (maybe these are there already???). But this would not be a holographic image - no interference is involved - diffraction would, of course, be involved in generating the wavefront as is the case with all wavefronts.
- In my view, holography involves a physical interference pattern which diffracts light to create the required wavefront , field , whatever you want to call it.
- I think the three of us agree that the current introduction is not satisfactory, but are not in agreement about how this should be done. Please feel free to alter my sandbox. Epzcaw (talk) 18:03, 22 September 2020 (UTC)
Any objections to the current sandbox version of the intro section?Joortje1 (talk) 07:05, 25 September 2020 (UTC)
Please check the referenced source about electro-holography. It begins with a decent definition of holography and also seems to confirm what I stated about artifical holography. Much like a photograph doesn't have to be printed, a hologram doesn't have to be an artefact (I can't see how there would be one in electro-holography). Although I think photo-realistic cg imagery shouldn't be called photography (if it is known how it was made; it could easily be misidentified without that information), I don't see any problem in calling a cg hologram a genuine hologram. Maybe that's the influence of sci-fi on the perception of what holography is, but there's also the fact that there are many applications of holography that are quite different from holographic photography (e.g. data storage). I believe laser holophotography was already quite different from the original electron holography. Presumably, holography was perceived more as a technical method from the start (while photography was much more about the resulting image), which clearly has since long been imagined to be capable of producing more than recordings (and applied as such).Joortje1 (talk) 07:05, 25 September 2020 (UTC)
- Whilst I see your logic, I don't think it helps much: the electron/neutron/optical holography pages will still need to share a common explanation of holography itself, which would be your Physics of Holography page. Except that the latter will then still need an introductory section for general readers, and that's exactly what we're struggling with here:( --Louis Knee (talk) 23:23, 26 September 2020 (UTC)
- I feel the simple definition that Louis Knee and I more or less agreed on
- Holography is a technique by which a light field is recorded and subsequently reconstructed in the absence of the original. The reconstructed image retains the depth and parallax of the original scene. With something additional about using interference and diffraction
- I feel the simple definition that Louis Knee and I more or less agreed on
- is clearer and is something that non-scientists will be able to grasp. Encoding a light field is not something that more people will understand, and is likely to put them off at the beginning. People will be coming to this page to try and get an understanding of how holography works, and it needs to kept as simple as possible. I am proposing to do a new article entitled Physics of Holography (started below), and will suggest removing the current section of that name in the main article to deal with the comment that the article is too technical.
- Most of the main article is discussing how holograms are made, so I don't think a Technology section is required at the start. Epzcaw (talk) 09:57, 25 September 2020 (UTC)
- Many years ago when I used to do outreach and lab open days, I used to start by describing a hologram as
- a magic window that freezes the light passing through it
- but while one can get away with that when there's one set up on the bench behind and you know you can follow up at a tailored level, it isn't suitable for an encyclopedia where users will copy/paste it into their homework. :(
- My own attempt at a definition is still in progress; at the moment it looks like:
- Holography is the capture and subsequent re-creation of a wave-front, by recording the pattern formed by the interference between it and a second, reproducible wave-front. Illuminating the interference pattern with this second, "reference", wave reconstructs a perfect duplicate of the original.
- Note that it makes no assumptions about the nature of the waves, and it precludes neither "forming" the pattern numerically within a computer, nor "recording" it by writing to some dynamic array rather than a static plate.
- I'll have a look tomorrow in some old A-level textbooks and see how they described it. --Louis Knee (talk) 00:18, 27 September 2020 (UTC)
- I like that the first part. I would be happy to go along with that. I suggest replacing the first sentence in the current article with that, and splitting the paragraph.
- Many years ago when I used to do outreach and lab open days, I used to start by describing a hologram as
- Holography is the capture and subsequent re-creation of a wave-front, by recording the pattern formed by the interference between it and a second, reproducible wave-front. The recording is referred to as a hologram.
- However, I don't think that other forms of holography reconstruct the object beam by illuminating the interference pattern with a second, "reference", wave. I know very little or nothing about them, but I'm fairly sure they involve some sort of digital processing rather than illuminating with a second beam. (talk) 10:36, 27 September 2020 (UTC)
- Don't have time ATM but: second, "reference", wave is exactly what they do. Look at Gabor's original idea: record pattern of electron waves on plate, illuminate with light waves, electron-to-light wavelength shift gives magnification. "digital processing" just means applying the reference wave numerically inside the computer, the physics is still the same. "Holography" just emerges from how interference and diffraction work and these are basic wave phenomena, so true Holography can be done in any sort of wave (as long as there's a way to record the fringe pattern). Not sure if this is clear as it's very brief. Thanks. --Louis Knee (talk) 12:34, 27 September 2020 (UTC)
- However, I don't think that other forms of holography reconstruct the object beam by illuminating the interference pattern with a second, "reference", wave. I know very little or nothing about them, but I'm fairly sure they involve some sort of digital processing rather than illuminating with a second beam. (talk) 10:36, 27 September 2020 (UTC)
- Yes, I agree that Gabor's original idea was to record the pattern, and use optical illumination. But that's not what happens in more recent electron holography:
- From Electron holography
- Reconstruction of off-axis holograms is done numerically and it consists of two mathematical transformations.[5] First, a Fourier transform of the hologram is performed.
- I bet though that those numerical transformations turn out to be equivalent to those used for digital optical holography, and involve knowing some phase distribution across the image (which is is what the reference/reconstruction beam is for). Unfortunately the digital holography page has little useful info and digital holographic microscopy also omits the reconstruction algorithms, so there's yet another hole to plug... --Louis Knee (talk) 00:06, 28 September 2020 (UTC)
- In acoustic holography, the signals from individual microphones are digitally processed using various beam-forming technique, i.e. summing them with added phase differences.
- Don't know much about it either, but again "added phase differences" sounds to me like a synthetic reference beam in disguise. That's my point - the underlying interference and diffraction effects are the same irrespective of medium or of real-vs-simulation. By starting from that core I think it will be easier to explain the physics and let the different applications branch off, into their own articles if needed. (And, anything that doesn't share that physics isn't really holography!) --Louis Knee (talk) 00:06, 28 September 2020 (UTC)
- In acoustic holography, the signals from individual microphones are digitally processed using various beam-forming technique, i.e. summing them with added phase differences.
- I don't know what happens with atom or neutron holography.
- Maybe
- Holography is the capture and subsequent re-creation of a wave-front, by recording the pattern formed by the interference between it and a second, reproducible wave-front. Illuminating the interference pattern with this second, "reference", wave, physically or digitally, reconstructs a perfect duplicate of the original.
- Louis Knee I can see why you were trying to avoid being dragged into this. I feel the same now. 13:28, 27 September 2020 (UTC)
- I think we are making progress, just slowly. The thing is that working on this eats time, and I only have a couple of hours to spare per week :( Worse, unlike journal articles, it's not as easy to control the scope of the work: changes to Holography end up depending on rewrites of related articles (computer-generated holography, digital holography, digital holographic microscopy, etc., etc.) and it cascades out.
- My old A-level textbooks don't have any mention of holography, nor do Feynman's The Feynman Lectures on Physics. We may only be making slow progress here, but then bear in mind Richard Feynman wimped out completely! :) --Louis Knee (talk) 00:26, 28 September 2020 (UTC)
- Louis Knee I can see why you were trying to avoid being dragged into this. I feel the same now. 13:28, 27 September 2020 (UTC)
- When I suggested a new article on Optical Holography, I should also have said that there should be an article Holography which would describe the general principle of holography (as in your definition) and summarise the different types, including Optical holography), with links to the detailed articles about each method. Most of this is in the existing article.
- A new article Optical Holography would then include most of what is in the current Holography article with the general bits stripped away.
- My Physics of Optical Holography article will in the main only apply to optical holography.I know very little about how the other forms work. Optical holograms record only the intensity of the interference patterns directly. Acoustic holograms also register the phase directly, but I don't know about any of the others.
- Out of curiosity, I retrieved the original Holography article written in 2002.
- Holography (from the Greek, holos whole + graphe writing) is the science of producing holograms, an advanced form of photography in which allows the image to be recorded in three dimensions.
- The difference between holography and photography is best understood by considering what a photograph actually is: it is a point-to-point recording of the intensity of light rays that make up the image. Each point on the photograph records just one thing, the intensity (the amplitude squared of the electric field) of the light wave that illuminates that particular point. In the case of a colour photograph, slightly more information is recorded (in effect the image is recorded three times viewed through three different colour filters), which allows a limited reconstruction of the wavelength of the light, and thus its colour.
- User:Epzcaw|Epzcaw]] (talk) 10:36, 27 September 2020 (UTC)
- A separate article for "Optical holography" seems like a good idea. But I'm not sure what the boundaries of that concept are, or whether that's the best term for the photographic recording version of holography. Noting your comment about other forms of holography, the definition in the main "holography" article should be even more generalized. Maybe something can be found in writings about the hypothesis in physics of the holographic principle (or "holographic universe). Wikipedia now calls it: "the description of a volume of space (can be thought of) as encoded on a lower-dimensional boundary to the region(—such as a light-like boundary like a gravitational horizon)." (my parentheis for wording that seems superfluous to a general context). In that concept it's not even a technique, science or art, but probably a natural physical phenomenon.Joortje1 (talk) 15:26, 27 September 2020 (UTC)
- I also liked this definition for the optical variation (presumably including real-time electro-holography): "Holography is a diffraction-based coherent imaging technique in which a complex three-dimensional object can be reproduced from a flat, two-dimensional screen with a complex transparency representing amplitude and phase values" (although I'm not sure about the word "reproduced" in the context of CGH and I miss the technical knowledge to judge te part "complex transparency representing amplitude and phase values". )It's from the article on electro-holography that I previously intended to refer to, but whose url I apparently mixed up with another one. I haven't read the total article yet, but it seems useful.Joortje1 (talk) 15:26, 27 September 2020 (UTC)
- I think the first sentence should be simple, and comprehensible to someone not familiar with the field. Some examples:
- A camera is an optical instrument used to record images. At their most basic, cameras are sealed boxes (the camera body) with a small hole (the aperture) that allow light in to capture an image on a light-sensitive surface (usually photographic film or a digital sensor). Cameras have various mechanisms to control how the light falls onto the light-sensitive surface. Lenses focus the light entering the camera, the size of the aperture can be widened or narrowed to let more or less light into the camera, and a shutter mechanism determines the amount of time the photo-sensitive surface is exposed to the light.
- Photography
- Photography is the art, application and practice of creating durable images by recording light, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as photographic film. It is employed in many fields of science, manufacturing (e.g., photolithography), and business, as well as its more direct uses for art, film and video production, recreational purposes, hobby, and mass communication.
- Topiary
- Topiary is the horticultural practice of training perennial plants by clipping the foliage and twigs of trees, shrubs and subshrubs to develop and maintain clearly defined shapes,[1] whether geometric or fanciful. The term also refers to plants which have been shaped in this way. As an art form it is a type of living sculpture. The word derives from the Latin word for an ornamental landscape gardener, topiarius, a creator of topia or "places", a Greek word that Romans also applied to fictive indoor landscapes executed in fresco.
- Higgs Boson
- The Higgs boson is an elementary particle in the Standard Model of particle physics, produced by the quantum excitation of the Higgs field,[8][9] one of the fields in particle physics theory.[9] It is named after physicist Peter Higgs, who in 1964, along with five other scientists, proposed the Higgs mechanism to explain why particles have mass. This mechanism implies the existence of the Higgs boson. The Higgs boson was initially discovered as a new particle in 2012 by the ATLAS and CMS collaborations based on collisions in the LHC at CERN, and the new particle was subsequently confirmed to match the expected properties of a Higgs boson over the following years.