Video

Hey, appreciate the feedback. This is why I decided to record with voiceover in my further videos :). Yeah, the subject of EV definitely deserves more attention. Cheers!

Hey, I guess exactly the same way I scanned a brick wall in one of my previous videos (czcams.com/video/U3AVpCA-wMo/video.htmlsi=0WlWvXnNuSvPTNUh). Roughness is way more tricky tho and to extract ityou need to do some subtraction between cross-polarised and parallel-polarised data.

:D I dont think so, at least not as long you keep the distance from the subject - as you can see on this video I intentionally positioned the flash very close to the surface. Not to mention, while AD200 Pro I used outputs 200W, it focuses the light on quite small area while AR400 spreads its 400W on much larger/wider one. I just wanted to show that light absorption is directly related to temperature. In the video about 'whitest whites' I am currently working on I set a black paper sample on fire with the magnifying glass and the sun just within a second while I wasnt able to set a white paper sheet on fire at all no matter how long and what I did. Still not sure if this part will go into the final video but actually might :) So if you want to scan some black insect using macro lens and use some strong flash light from close distance to illuminate it, you can actually burn/damage the specimen. But if you use standard lens - which needs at least 20-30cm of distance from the subject to even get focused on it, it shouldnt be a problem at all. And even if the subject gets warmer, it wont ever get hot enough to ignite :).

@@GrzegorzBaranArt Good 😅 Thanks for the detailed answer. Glad i am not interested in captureing insects haha

Hey, I dont use JPEG at all. I always use RAW files and convert them into TIFF during image pre-processing/photoediting stage. Next, I use these TIFFs for reconstruction. Yes, there is a big difference if you do any photoediting adjustments on 8bit data in comparison to 16bits. Basically there is no space left for 8bit data to be readjusted and each tweak comes at cost of data loss. Depending on photogrammetry app, 16bits can be better for image alignment. I dont think there is much difference during the reconstruction itself (of course as long as you use 8 bits just as a data container without further tweaking. Please bear in mind that while RAW data or TIFF can be turned into JPEG, JPEG cannot be ever turned into RAW/16bit TIFF - I mean technically it can, but the data trimmed down into 8bits cannot be recvovered while reconverted back to 16bits. I dont recommend 32bits for reconstruction or image alignment. 14-16bits is totally enough. Hope that helps. Cheers!

Not sure how would it help unless you meant it as the way to reduce the amount of environmental light bouncing (pollution). Bear in mind that the subject needs to be kept in cone of light anyway.

thats a very good idea and actually very interesting case. Unfortunately chances to get cold, frozen and clean snow I can use and measure in the UK are close to none during summer, and very challenging during winter so shamefully need to pass on this one :)

Thanks Barnyz, he just told me that isn't really interested to be measured and will bite my hand off if I try ;P

Thank you

Will do my best to make this comparison as informative as possible. Even considering some serious magnifications. Yeah, I am so happy I reced samples from these companies for this video - it would not be ever complete without them. Sill a lot of work ahead, especially as mentioned I am still in sample collection phase as a few left - like whitest OBA and non OBA samples of paper and fabric etc. Cheers!

Dziekuje bardzo. Zupelnie zgadzam sie z 'mobile based photogrammetry', nawet planowalem nagrac na ten temat dluzsze video. Natomiast nie przeskoczysz fizyki i jest powod dla ktorego aparat i obiektyw sa wieksze i ciezsze. Szczerze mowiac, zjecia z drona (z wylaczeniem duzych dronow jak Inspire etc), porownywalne sa do zdjec zrobionych ze sredniej jakosci telefonu komorkowego i to trzymanego w jednej rece stojac rownoczesnie na jednej nodze ;). Pozdrawiam

Мобильные телефоны с глазком линзы в 2 мм, с дикой дисторсии по краям из-за широкого угла, с ужасным ГРИП из-за диафрагмы в F/1.3 полная ерунда для сканирования, даже самые дорогие, Вы правильно сказали, физику нашего мира не обмануть. А ещё уже лет пять минимум ни одной фотографии с мобильного без обработки нейросетью получить нельзя, так что это не фото, это картинки, нарисованные встроенной нейросетью по мотивам оригинальной фотографии с сенсора, которую никто никогда не увидит.

@@YN3_ I have pixel 7 pro and i use raw files that were not "enhanced". I realize that it's not for proffesional use case. My point is that it is blazing fast and results are much better than I expected. For me it's acceptable for making souvenirs or something. I also have Nikon DSLR which i use when I want to be sure that i have best quality possible. Try to be open minded and not maximalist.

@@YN3_ as said, physics cannot be fooled and there is a reason why professional camera and lens are bigger. But it doesnt mean that you cant scan with mobile or a drone. You can and people do. Sometimes mobile or the drone are the only options. This ground surface in my video was scanned by the M2P drone and its quality is definitelly good enough: czcams.com/video/i3TYuQTJedY/video.html Of course the quality would be much higher with the camera and cross-polarisation etc. but if you really know what you do, its still fine. Mobile tools have apps and options (often called a PRO mode) which turn all these fake 'enchancements' off. Yes, you can scan with your mobile and get quite devent results.. of course it will be more challenging than scanning with serious equipment and result with lower quality.. but as long that quality is for someone good enough its totally fine. This is why I plan to record a video about that at some point, as its quite interesting subject. Recent mobile cameras can be really quite powerful... especially when you compare them to 10 years old DSLRs ;) So I would say, a lot depends on skill and knowledge of photographer and how much you can get from your camera, than the actual camera. Cheers!

Its a good idea to add whitest textiles. Will do my best to find some samples. I plan to cover subject of OBA in detail and present OBA substances with and without ultraviolet light which makes them to illuminate. Cheers!

No probs, anytime :)

Hey, I cant make decision for yourself, but with limited budget I would certainly pick A7RIII over way more expensive A7R4. When it coems to photogrammetry, lens is way more important to camera. Not to mention that reconstruction benefits more from higher number images than their resolution. Image resolution can make difference when it comes to any single image based reconstruction like Image2PBR or Photometric Stereo. Hope that helps. Cheers!

Still Details Capture

Thanks, I believe I answered this question already in this video and I even shared some examples. In practice, it all depends, but the short answer is: yes, you can capture with cross-polarisation without camera flash and use some LED ring instead, but you would need to capture in environmental darkness. You can even use set of external ambient lights which arent ring light, or light tent etc.. I would say, sky is the limit here, but the best results and the easiest capture process is with the flash light ring.

I guess you can, but sensors saved me many times from being hit by a drone, not to mention that switching is too much hassle since. After dozens of such landings catching the drone this way is really super easy and natural. It just takes some practice.

To zalezy od przypadku i tego co chcesz osiagnac. Robienie podwojnych zjec jest stosunkowo skomplikowane. Zdjecie polaryzowane i niepolaryzowane powinno byc wziete z dokladnie tej samej pozycji kamery. Mozna to obejsc poprzez automatyzacje lub podwojny skan w dwoch wersjach i reczny matching. W praktyce staram sie unikac takich przypadkow i uzywam full-crosspolaryzacji i jednej serii zdjec.

@@GrzegorzBaranArt Bardzo dziekuje, za tak szybką odpowiedz. Robie skany kilku toreb skurzanych, set zdjec bez polaryzacji (zakladam ze, bede zdejmowal tylko jeden filtr z lampy, zrobilem luzny zaczep, ktory pozwoli mi nie ruszyc lampy, ani aparatu) bedzie mi potrzebny do zrobienia mapy roughness. Wydaje mi sie, ze to chyba jedyny sposob, bo matchowanie sie pozniej dwoch oddzielnych setow zdjec to jakis koszmar

Polecam moje ostatnie video o naczarniejszych farbach: czcams.com/video/vtUhUeOo5mM/video.html Jestem swiadom, ze malowanie nie jest moim najmocniejszym skillem :)

Thanks. Light is the light and depends on spectrum it covers, its intensity and clarity, but also on environmental light pollution, distance from the subject and everything I mentioned in this video. I plan to make a video about light sources but need to save about £3000 for a special devide I need to use to measure spectrum detail so it is goint to take some time. Anyway, imo the best tool for such captures is the wireless camera flash light with TTL feature to auto-adjust light intensity, as well as some decent, real camera equipped with lens, mounted on solid platform which prevents camera movement and micro-shake. Of course any light can do the job if used properly. Sure, you can use your mobile and get some results and it all depends on what do you really need and what is enough. To be honest, sometimes you dont even need photometric stereo, just some 'single image to PBR' processing tool which does the guess on values - or you dont even need a PBR data except the albedo -for example this is how I made this flower for the glass vase scene here: www.artstation.com/artwork/WBO8qQ

@@GrzegorzBaranArt Hey thank you so much for such a detailed explanation! I tried with image to material in Sampler, but imo photometric stereo prevents the blobby cloudy details made during image to material. I have not yet started a job in the industry, so a bit short on supply haha . Therefore I am considering buying a cheaper solution, I don't need very high fidelty, but it should be passable! Tried with a ring light with very soft shadows, did not turn out great! So I will have to look for some more I guess!

You are welcome <3

I think so, its just the flash at the end. As I understand it all depends on the transmitter setting

Hey, I am not sure what you mean: you can change battery anytime, usually when its out of juice. If you meant battery removal to force overheating counter reset, I dont know as you can reset overheating protection simply by turning the flash OFF and back ON without waiting 10 minutes for it to cool down. I do that sometimes when I am in a hurry, or when there is just a few final shots left to finish the capture and I already know I am gonna move to another location after so the flash will get time to cool down anyway. Its also external conditions depentend, so when I shoot in cold windy weather which helps to keep the flash at lower temperature it is ok to override this protection when needed. When I shoot in a hot sunny day, I would recomment to check flash temerature with hand before even the overheating protection kicks in and let it cool down when needed. AR400 has is a quite simple and cheap flash and a lot depends on user. As far as I remember the OFF/ON overheating protecion workaround works just 2 times in a row and the 3rd time forces you to wait 10 minutes before you can use the flash again anyway. To be honest, I never used the second reset as I I dont want to damage the flash. This protection is built for yours and flash safety. Its just an electronic counter which doesnt take any temperature reading into consideration as there is none - hence the manual option to override it. Bare in mind that the temperature doesnt affect just the bulb, but also electronic components inside. So I wouldnt strongly recommend not override the protection more than 2 times even if it is possible and even if you shoot in winted. But I never tested if it can be done through battery removal and dont have any plans to test it as I need my flash. Hope that makes sense :). Cheers!

@@GrzegorzBaranArt Thanks a lot for your answer,Love you! Regarding the battery, I thought it (battery) was overheating and not the lamp, so I thought to replace it if it overheats)But now I've found out that the lamp itself is overheating and it doesn't make sense. I have 3 more questions and I will be very glad if you answer: 1)When taking a portable photo in the sun, when the AR400 lamp overheats in 40 photos, it would be better to find another option.I found out that the Quixel(Epic Games) team uses the ELB 500 TTL, it is quite expensive, but the problem is not that, but that I did not find how to attach this lamps to the camera and I will have to develop and order a mount(for rig) (or ask for its parameters from Quixel) which could be a problem. Do you know any better and more powerful analogues of the AR 400?The price is not very important) 2)Also, for fast studio photogrammetry, I decided to use a continuously rotating stand and continuous series of photos to scan a large number of objects faster.This requires a very low shutter speed (1/4000;1/8000) since the object will be spinning continuously and I do not need it to be at least somehow lubricated.To do this, I will need to buy 3 Godox QT 600 or 3 Godox QT1200 (2 in front, 1 on top) the question here is whether there will be enough light (taking into account polarization) for a 1/4000 / 1/8000 shutter speed, I will test it in the studio where such equipment already exists. In your opinion, will this idea work? 3)I'm thinking of buying a Sony A7R V with 61 megapixels, is it a good choice for photogrammetry (I need 8k textures)?Maybe I don't need so many megapixels and I should buy the something simpler like Nikon D 850 with 45 megapixels, it will be 2 times cheaper.

@@mrlogo3733 no probs ELV500TTL is superior to AR400 because it outputs more light and has TTL which gives advantage when it comes to outdoor captures without fixed distance. I never used it tho as it was too expensive for me and AR400 was good enough for the job. I had a feeling that Elinchrom was also providing a handle kit with their product but if not, you might need to develop your own custom handles. To be honest, nothing stops you to develop your own rig using whatever is out there on the market. For example use multiple AD200Pro flashes.. each outputs up to 200W and have TTL so when you combine 4 of them you get 800W and TTL etc. I would say, sky is the limit here. Regarding the object movement during capture - everytihng depends on how much detail you want to get from your captures. If you aim into the highest level of detail, the subject should be still during the capture, and there is even some delay recommended to make sure all imcromovement is gone too. The smaller the subject and the higher the level of detail you expect to get, the more relevant it is. If you aim just into the shape, you can even get reconstruction from video. With the object sitting still you can get a better depth of view etc. but as said, it all depends on the subject type, size, capture contitions etc. and sure, you can capture things when they move if well illuminated and you are fine to sacrifice some quality. Its all about the balance and when you want to get from it. The texture resoution from photogrammetry captures doesnt depend on matrix size, because you capture many images which next get combined into a single one. Sometimes image size can become a bottleneck when it comes to data processing. Its always better to get more smaller images than less larger, therefore, camere lens and sensors physical size are more important to image resoution. Yeah, Sony A7RV is a good camera for photogrammetry. I cant tell you about your shutter speed as it depends on camera setting, distance to the subject and amount of light, but in certain conditions it is certainly possible to shot at 1/4000 or 1/8000. Btw. bear in mind that flash duration on its full power takes about 1/300s, therefore you wont be able to utilise full amount of lught it outputs in 1/4000sec. and you will need to compensate for these. This is why turntables stops and delays shutter after they did... to compensate all of that. But as said, it all depends on what you want ot get from your capture.

Thank you, veeeeery appreciated <3

THanks, I never had any tiling issues with color equaliser.. anyway, I dont use this technique anymore for scans as I developed much better and accurate solution and work directly on raw data - but this one is still an option for some hardcore cases :)

@@GrzegorzBaranArt thanks for the reply. It's reassuring. Maybe all it did was reveal the tiling errors I already had! or maybe because my version of substance (2020) is old. I'll give it another try.

It turns out, the Color Equalizer node is unique, it requires you to check a box instead of using the tiling settings. How infuriating. It's especially annoying to me because I like to scan trees, for tree bark material - and since they already tile on one side (since the tree is a cylinder), I don't want color equalizer to tile vertically! But the check-box doesn't have the option to tile horizontally, vertically, or use both, the way _everything else_ in Substance Designer does. 😵

@@josephbrandenburg4373Yeah, you need to set the 'Tiled Input' flag if the input is already tiled. As said, I dont use this node too often as I found much better and less data destructive ways to handle such cases. Equalising isnt free and affects quality. Its a math based one so its pretty dumb and while can do the job for subtle cases, I found this quality loss totally unacceptable for more extreme cases - hence finding ways to reduce need of such operation - increased capture consistency, color calibration and direct pre-editing of raw-data before reconstruction etc.

Thank you <3

Thank you Barnyz, verry appreciated <3

I just shared my experience without any cheating in detail. I didnt play with other screens but I heard that it depends on the screen and case and its quite random. So maybe I wasnt lucky or maybe you were very lucky. I bet the truth is somewhere in between. Cheers :)

Thanks

Thank you. Nah, I havent but AR400 flash ring I own spreads the light widely while AD200Pro focus it on a small area. I am sure even the coal can be set on fire this way as the smoke we see already proves that combustion took place. Magnifying glass would just focus more energy on a smaller area therefore multiply its intensity, so I am 100% sure that this way I should be able to provide enough energy to ignite any, even white paper surface.

Sure, whatever works for you bud :). Moving heavy camera around hanging on arm tho makes camera stabilisation a bit more challenging .. not to mention limited size of moving background and lack options to play with its distance to maximize benefits of light falloff... unless you have really very large and expensive orbit tool. But sky is the limit here and the option I shared is just one of many. Cheers!

Thank you , very appreciated <3

Hey dude <3. Actually I dont, I kind of wanted to verify if something that basically absorbs crazy amounts of light can set itself on fire just because of its color lets say.. in a hot sunny day ..and it might. Of course the flash from that distance is much stronger to the sun, but it flashes just for 1/300s while the sun can provide solid strong light for much longer. Cheers!

Linear vs sRGB is just a math conversion and linear color information to be honest is quite useless when it comes to digital color representation. So my guess would be that these spectrometers and colorimeters were designed with print/ink/paint measurements and computer screens in mind, therefore sRGB makes more sense in such case. The PCE2 I used to use, outputs linear values and it was painful to convert these into sRGB to get their digital color representation before I was able to apply them - I had to take measurements, put them into an excell file with conversion equation there first .. now I just make a measurement, take a quick look on a screen and apply these results to my digital app - usually Substance Designer - in no time. When it comes to color comparison or accuracy, it doesnt really matter as the app also outputs color information in way more accurate formats like CIELAB. I am also aware there are some color convertors on their webpage which would be cool to have in the app too but I didnt notice them there. Luckily, when you store the data through app - like I did in this video - you can access it automatically on your computer screen from any computer automatically through their dashboard (dashboard.nixtoolkit.com/) and simply export whatever you need in CSV format, so any conversion of these are quite easy for anyone who might need that. So I would rather prefer sRGB to Linear, but I totally agree that it would be cool to have a choice/option for such added somewhere to the app.. unless it is there already and I just missed that.

@@GrzegorzBaranArtYou can display the data in XYZ and Y is your linear luminance

Thank you <3

Hey, to be honest I didnt consider this option as I wasnt unaware of that, so thanks for the advice, very appreciated. I consider some different options tho.. I chose to use standard paper because it's something everyone deals with on a daily basis. I was hoping that a double coat of paint with enough time to dry would alleviate this problem to the point where the base surface wouldn't matter much. I was also considering a solid, smooth surface instead that the paint wouldn't soak into, but I found somewhere that solid surfaces are not recommended for some of these paints because they may have adhering difficulties. Finally, I considered measuring the paint itself using a liquid measuring adapter, but I decided that the method of my choice would be the most representative. Its definitely something to improve tho and consider in a future and to be honest, I might give it a try even just to see the difference. Cheers!

Yeah, good spot. I fixed that later on a dashboard :D

Thank you <3

Niestety nie mam dostepu do Vanta Black zeby porownac - nie mowiac juz o tym ze 'vantablack requires professional spray systems and training to apply' :)

Thanks. Hope the subject is interesting and enjoyable. I initially planed to keep it much shorter but I failed :)

@@GrzegorzBaranArt honestly i cant speak for everyone but the longer GB video, the better ;)

Thanks, yeah, I am aware that I totally suck with painting and have a lot to learn :)

I believe it should help but high temperature affects structure of crystals polariser is made of, therefore damages polarisation properties permanently. So after applying the temperature you turn this sheet into transparent one which does nothing :). As far as I remember I covered this somewhere in this video.

@@GrzegorzBaranArt Yea my fault. I made the comment before watching the video till the end. Well then there is only some chemical left. Anything else appears to me pointless. But anyway interesting video.

@@MrGTAmodsgermanAs some shared in comments, some screen polarisers are easier to separate to others. If I recall correctly someone mentioned that polarisers used for TV screens are easier to separate to these mounted on computer screens. I consider my attempt to get one here as a failure and would rather purchase a brand new, clean polariser sheet that waste my time trying to get another one this way :D Cheers!

@@GrzegorzBaranArt Interesting 🤔 I saw a comment here about those Iphone screen protector which might be the easiest option if i understood correctly.

I am sure anything can be recycled if you need it. I am afraid tho, that light efficiency from such panels isnt the best and woudl rather recommend strong, color calibrated LED panels for such job. Cheers!

Thank you, very appreciated <3

You are welcome <3