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Beginning Lighting for Machine Vision
Part 2

Beginning Lighting for Machine Vision
Part 2

Part of the AIA Certified Vision Professional-Basic program, Daryl Martin of Advanced illumination, teaches lighting geometry and the basics of illumination.

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Click to View Transcript okay this is session 2 basic lighting techniques for machine vision partial rightfield light fell if we take a look at what I call retracing all are doing here is examining how to light is interacting or wide-angle or direction it’s coming from under the surface so in case of partially all higher than 45° tends to come on the surface of a higher angle and also has services of placement of bounce straight back okay toward the camera bundle services that all are dimpled or whatever the case may be it’s going to deflect the light or scatter the light away some camera will not see that it has important ramifications on all the contrast patterns that you might generate a sample so obviously specular surfaces are going reflect that glare triangle all flat smooth surface is certain reflect more evenly we can also take advantage of all that look to be pattern as well with virtually years and are feel example home angle light 45° over less of course as I said okay all this had to be a bag of brittle and all I think what they were actually looking for was trying to inspect the surface were plastics of the facts that now you can see to the probably use the high angle way all you got contrast pretty decently you can see part of the upper surface the lower surface does not show up well at all… Completely washed out sort of original claim was that he no surface come back to the camera all now I think that same sample and put it under a circular dark to light you can see considerable difference in terms of the quality of the image all men you can clearly they go where the defect was out after seeing it defect in the right-hand image you look closely yeah okay Tennessee where was all but we really need all of our criteria are either did we meet we met criteria wanting to pretty well we did not beat number three is not really very robust because the next sample and next bag of peanut brittle it comes nonaligned may reflect completely differently again including the servicer or the defects of the dark to light much more robust much more sample specific sample appropriate for this particular all application and so regardless of how they’ll bag is position oriented over the surface is still going to clean image excellence of all much better technique for this titular type of analysis IBM will unit dark field light with retracing all floor angle all epistles flat surfaces tends to scatter away in the words of the inverse of what happens in break the same thing with her dimples are areas where the recessed areas all sometimes it may sound very straight back to the camera sometimes is exactly what you’re looking for in a case of the scratch on your surface that’s a perfect all way through to care all we need to imagine several things here using dark to light you can really emphasize changes in height and precisely all contour shapes all things let’s look at all services listed as assured earlier is very dark in his own way, people will together with a sample okay again retracing rightfield our same sort of surfaces here light reflecting straight back to the camera though there easily become a very bright terms or you can see all when it same rightfield light hits the other services scatters away there and attend reflect back a little and which case you get a darker pattern and if you look in a dot matrix code which I see quite a bit of all in terms of RRTand in the auto industry in general this is a sort of image you similar words what you end up with is all bright background and greater pits because all items being scattered away from the pits all now obviously we take a look with our field conversely inversely you see the same thing are the opposition said all low angle light of bounce when the surfaces but not as much reflection and some of the dimpled services again are going to like collected ‘southern Québec writer which tastes as you might expect to see an image like thisrie work with engineers daily and you know I get asked this question will which one is better and there is no simple easy answer to that arm again it depends on what works best for you all I personally all is I have a choice I like the dark field because that background is completely washed it’s gone stark you don’t have any issues there with discolorations all with you can have opposite ammunition was if you got pits that are part of all the surface work with all seen those cases where the surface so they put all matrix codes on curved surfaces on dimpled bumpy services we’ve all been there we see that so it’s hard to do it anyway but so I prefer the dark field for again you can mind you got a have a sample Colston part of the place to be close to the sample all and to all that can create a problem sometimes and so just as a lot on your application now another question all is then asked as well do I need a green light to do this application I say no because really just need light from the same direction because all the pits are going reflect back the same way and so it didn’t change the shape okay and her words its nondirectional science is multidirectional be better to put it so you would necessarily have to user circular light you could assemble on the back lighting a little bit here all back lighting as I said before really generating a silhouette on the surface obvious that uses our edge and whole detection all also useful for translucent and transparent materials okay for Digi or were just presence absence of parts all orientation of parts the data robotics is also heavily used for pick and place of the places or something almost lines all and obviously gauging all there are some caveats with the with a high accuracy measurements involve all those Leno has been discussed in the other classes all I mentioned early on about all late diffraction okay and him and how it might impact your back lighting selections in all their mind that this is a minor difference is fleshly exaggerated here so you get a sense for what it’s like all but in light tends the babies around obstacles okay and so all this of diffraction angle is I said before is a functional Biddulph the way for okay and so a longer wavelength some more diffraction you have a shorter the wavelength the less diffraction have all and you can probably envision no scenario where using white light which case you’ve got chromatic aberrations you got information from every single wavelength in that range and so that has an effect on the quality of your edge detection as well so all night you thinking will be okay if I got less diffraction with blue Max use blue backlighting for every sample that I look at no you don’t have to really all there are a lot of reasons for not doing that all and again the difference here is his intensive percents so it’s not a huge difference I say if you’re grasping for straws and doing everything you can and try to get the most out of of it then it’s okay try try a shorter wavelength see what happens at all so it least at least use it are you ready to high accuracy gauging very critical on the edge detection all use monochrome like a user red or blue or green or something like that all the shorter wavelength is better but and I have customers who use the IR backlighting as well that doesn’t seem to be a major hindrance of time of testing CL works for you once again Kathy Ivins or another before Om collimation is also a useful issue all the and of in the case of backlighting at least in the case of macro backlighting all you can you sell film is not a perfect collimator by leaves all all but it is better than nothing and so let will prefer a vertical orientation in so anything that I like to touch on is well all back backlighting the longer wavelength will penetrate samples much better and sometimes as useful served backlights are quite so of different types out there but example or all this really transparent materials application is as mature as application to take these cats turn them over okay and I might do something labs you can tell all of you spray feel like registering light and looked at the surface well really tell us anything wrong with the insider that Because it’s all pretty much the same out here however all I take these even though their upside down all little on one acolyte you can still see where there’s some policy some missing Liner on the left-hand all Underrate image and of course I can do what do one better by flipping it over all I’m getting a little bit clearer picture and you probably asking why is this case caters reasons because all of the Over its much closer to the samples you got more intensity okay cancel so closer to the sample all the better resolution as well so spousal defocused looking than a bit here’s ears of the lives of motor example of small pile okay all the blue-green bottle of say you are tasked with measuring the fill line in this particular model K self versus HDD 80 red backlight which are ready as soon though you put the lowball on here and you fired up to your home I I can’t see anything so well I guess rated work so well in so all us try something else to startle reflex so we tried IR releases of that penetrate samples better well does it necessarily or does it always portion home and here’s a classic case were of course not all I gave you limited to handle those items Bailey’s you might think all the blue-green bottle and so you can probably guess what we’ll use next wares blue to value have been treated all and all piping what’s critical here to know is that in the this case yes it were all but it’s not always the case okay and it’s again is something you have to try the original real way to be sure about it at home I’ve had sample bottles that were a certain color and try to same color lighting and drove the light was not penetrated so sometimes depends on the materials properties as well as the color of the sample okay all for whatever reason plastic all beer bottles brown plastic beer bottles all red long wavelength red light works very well 695 all IR won’t go through even also longer wavelength will again depends on the interaction with that particular sample So a something in mind just thinking them just because it was blue and green business or any of the blue-green light will penetrate but it’s worth a try in and in all fairness know you can hold bottle of the white light and you could see the level and so I knew that there were some wavelength within the visible range that would do the job site is kept Plantronics life honoring one VNS something you have to do as well start working on these yourself all the way field lights all again can be different varieties don’t some of these X you’ll diffuse you splitters flatter planer diffuse lights cylinders is really a function of these lights were using here are also the same sort of diffuse lighting technique is the same approach will minimize a contrast on those features okay you want to generate an even reflection as opposed to a sharp radiant reflection and so again you for the firm with the dome light quality to illuminate it minimizes glare and it really does all simulate what you see on a cloudy overcast day you don’t get the sharp all channels are pages as I was adding really is that the light is generated inside the home is involved in all over the inside back down to the samples from multiple directions and to be fair this grant should delay should be locals relents Scalise at some bit too far away you can use away but think about what you’re doing is so you take a diffuse light and you move it away from the par at solid angle gets smaller and smaller celebrity so you not you have a diffuse light you have a directional lighting is exactly what you don’t want to use all that way so than my all couple examples this is a glass rod we just had basically read the code to print on top of that game I noticed that the down the center you see a line outline all is not part of sample beltline is generated by a little cold at the top of the lamp itself. The light reason for that is because all that like this being generated any insight is some of its human rights treaties that will open and so it’s not getting back to the sample ballot depending on your sample let me make a difference and it may not so titular case it did manner we were certainly able to to do what we needed to do so was unacceptable all compromise here’s another example am probably more appropriate want all trying to be printed: on the base of the parking okay and in this case we took advantage of the fact that you know it’s so concave surface all and the dome is very good for concave or convex surfaces are all we also took advantage something else, talk about a bit which is changing in contrast based on color all in the vehicle front all the print was verbal okay and so we wanted to find a way to maximize the contrast of the print against that background okay so we use a particular color political dental we talk about color looking Ray tracing once again all full brightfield you knows the difference in contrast between the editor is difference of of how they operate with a diffuse of full brightfield versus impartial breakable brightfield tries to get lights come back to the sample regardless of the angle which it was incident on the surface of dimples and bouncing away it’s actually no attacks is still getting some of its getting bounced back to the same because it’s incident at different angles multiple angles plus a difference there really all again I’ve mentioned all curved shiny parts contrast to scanner deemphasized a symphony want to keep in mind as well you do lose to the image density softer way looks of this is acceptable and does the job that’s pretty so once again out the pseudo-of of the dark fuel effect family on any other diffuse technique all banks you’ll diffuse illumination all this is a effectively a beam splitter in the middle of the optical passel lights generated on the lamp there to the left is the base of the beam splitter down of the sample back up through all these splitter Dan all a new camera so very good for non-curved and reflective surfaces all my you can see right away caveat to all that is okay Scargill to 50-50 beam splitter twice and so what happens to your intensity intensity goes down a lot in so all you have to keep that in mind by his example of these editing grieved of letters on a flat surface and you can see flat surface reflects brightly because lights coming basically straight down is a sheet onto the surface and what’s happened is the the of engraved surfaces are bouncing and scattering light recently come back with much less intensity solar dark so it’s really you generated instant contrast and it’s very sample appropriate contrast if what you’re after is identifying our over reading or are there fine all the characters for example and I believe this is a perfect example for this particular all light all misses of sealing surface of the pop bottle are you know us and left outlet and imaging better really nice bright consistently even white ring as the very planar surface perpendicular to through the light itself okay and all so I would expect based on what we’ve just understood here will learn is that this surfaces reflecting back very easily so that would imply that there are no defects very smooth and so I think that same surface and this makes him very thin concert or tears or are marks not you see right away and see the difference okay so the sample on the right is not is nearly as clean a solid surface and so will I like this is perfect because your excitation advantage taking advantage of reflective and his pulse of trying to get around looking at that retracing once again to the light is mostly coming from a single direction as a sheet on the surface and so is is you saw in the previous example of glycated souls of both dimples were very various times to scatter away and so you have a darker surface coming back now you know something advantages smaller ways all if you got enough intensity you don’t have too much of a range in height differences this is a great way to measure relatively speaking to measure differences in height all you remember the inverse square law terms of the intensities and so if you all higher surface which is much closer to your sample scanner reflect back much brighter as opposed to the service which is a bit further away all reflect back less intense but because inverse square so you can take advantage of those as well angles the same thing all got mangled it shoots a laid off away all that is great for picking up differences and in homes or angles on a metal car very very easily HYBRID all the flat diffuse light and it’s really as she laid distracted again downwards home but it’s relying on an angle of incidence is much as it is all the diffusion it’s having inside the sample surface itself and so it’s like the old a few sites all and again it’s a hybrid I think the advantages that all eight can be used to longer working distances and save dome light are you still have the negative issue of the viewport at the top which can cause some issues with non-reflectivity there and have a dark spot to elaborate uniform bright sample and that they see that right away all anyway here’s another sample today up my dump your real-world sample but all this is a pharmaceutical tray okay and if you look at each one of those little soldier dies in the middle is is actually an individual well located was replaced samples and the sample size a whole whole thing and phrase of all 5 x 7” roughly 6 price of 6 x 5 Mary all is one of those wells has a laser engraved to you matrix obviously was you have superego for resolution and Bill take out then and and look each one of these individually so I can resume up your usually a fax or I want to do is step you through the differences in terms of what each of these lights does for this particular sample and one of my thoughts was a wall coaxial brightfield light might be okay during like a sea to see the the the matrix there’s not very clear all very distinct in some cases in fact gets overwhelmed by the surface detail of the plastic itself ugly these are plastic all though not necessarily good choice okay so you read my not so good maybe of more robust job maybe but below is the only issue I see is each of these wells is about 5 mm and so you can see on overwrite the lower right corner all you can see where those the angle light was nascent vignetting based on edge of the surfaces okay and this case it made no difference and so that’s a perfectly acceptable it was was nascent vignetting based on edge of the surfaces okay and this case it made no difference and so that’s a perfectly acceptable as long as you don’t have that circumstance where could they yet that’s a good solid solution all online is no good we have done better perhaps so I thought I’d try to coaxial which person I thought would do a great job and you are you notice you see the invert sword inverse pattern here all inverted black to white weight the black but the contrast levels are very good all nervous systems could probably handle it okay maybe not but it’s you still doing a lot of processing and know what let’s get the better image in first out there the system having dual extra processing overhead so fond to coerce the will my expectedly better out of this to him for whatever reason the multi-angles did not produce the level of contrast and meet in fact it’s probably worse and most everything else is very clean clear all terms of ages and things of that sort all but obviously for trying to read the matrices that’s not necessarily the best choice well was left as you can probably guess Mr. flat diffuse it is either that though we certainly got a very good image for this okay all we don’t have the vignetting problem we don’t have the angle problem all if we had to have the sample the light back off from the sample he probably could intensity is sufficient all so good choice and all I wish I could tell you which one were frankly I thought that don’t would be the best choice itself but clearly he saw the differences are sold by I differ Litman doing this for 15 years and it sees easy to get full so test it when you can reference material here really for the advantages and disadvantages of the different techniques rightfield all dark field full brightfield all Palm pits I think it’s important to understand when these can be applied when they can be applied okay and that helps you right away front because quite often you’ll perfect solution would be my this is beautiful bolide okay but no one put it dome light over the sample because I’ve got too much in the way or an Operator Pl., Arafat samples flying by some ridiculous rate was wildly go haywire knows everything happens in the doesn’t damage or whatever so all you have to weigh those choices and oftentimes I think it’s fair to say that their secondary choices occasionally are compromises that can be made so this is you are aware of the applications fields of each of these techniques since it’s useful to know all my try to work itself and an older more graphic graphical form all in terms of surface reflectivity and text your shape at all idols explaining to do on this one but if you plot increasing surface reflectivity to the right versus all difference in surface texture and/or shape all Manzano y-axis flat basely to curve and of course reflectively from map to your specular all you have to change it technique for all digital client to the particular sample okay and I have what’s called the geometry independent area there all if you think about it for second you got a flat surface is literally works best for you because you know you may not have issues with reflectivity necessarily so brightfield lights perfectly fine you could very well use an online business that met criteria for specifically what you’re looking better all now as you move however as you move from upper left to right or to Bob all you had to change it technique. And so as you move to them your specular you made you well look at the diffuse lighting in some sort be darkly lighting again depending on what you’re doing you all and you move downward from flat to leave and find her fees are curved surfaces you also go look at all of you diffuse light or a cylinder sort of approach so is really what this so this slide is all about us to look at the inspection environment here little bit as well again I know these will be covered as well much better than I can do here justice almost felt like there important to know all but some of the constraints you have to be thinking about these when you develop your liking solution all access for your camera your lens your lighting okay in other words what’s going on in F3 you working volume around your sample what do I have available all was the size was the shade for that volume in other words how close how far away do I need to be with my lady and how close and again if that’s important as well so those constraints you have to have a of some basis of his you start developing your application or characteristics I’ve been I think again all these will have some bearing most assuredly all what’s going on with your samples a movie is it moving but indexed all the stationary course all is moving one of the speeds and feeds okay is truly an advantage that something it probably should be discussed in advance classes while all the only benefit is what are we expecting terms of our own times all our duty cycles are expected pulse widths all things that sort of power presentations of anyone you know it is a consistent Holman orientation and position whatever the case may be that it has an effect on your sample are your analysis all is there potential friendly big one as well ergonomics safety to claim in issue okay if you’ve got a Manzano will burn operator intervention at some point interaction at least all are certain things you want to do a great example is seen off I were working on a line I would want to have a red flashing light my face all day so maybe there’s another choice well maybe IR’s a good choice and so all sorts of things have to play a factor in it as well and I’ll make him be an issue sometimes do more applications examples here this was just the barcode of brief you have printed self barcode under cellophane wrapped package that all all step you through the difference of types and all this was a modified I said before that it actually use these later life is very good for the flat reflective surfaces swell what I’m trying to do my trying to view the service of that cellophane know what makes you trend in who is view that surface under the cellophane and so that was necessarily betrays you can see there’s a lot of far reflectivity reflection here all online is that you could probably get a system to measure that but who knows what’s coming up with an example comment on the line of me where will be totally different in may be reflecting on places where you can’t get a good quality read often windy cold so step through some of these other choices I’ll Rayfield ringlike okay same thing all okay but how could we do better QB take care that issue with with the spec specular reflection altogether and start filming line Gano case where guns are gone from the brightfield techniques to the dark field okay you can see the most part that light got get a laugh angle through the cellophane reflected back up and allowed us probably do pretty clean image on had sample all I would venture to guess that that’s probably adequate must it has some very strange things happening with her cellophane wrappers all you never know what you know again all met the two criteria maximize our contrast for Britt we needed minimizer countries from you don’t need it all men bring much probably coppers the robustness part two but again no week is probably still do better. Right and this just happened to be a barley okay when you’re a light at low angle and I think that’s probably a cleaner image and so assuming everything else was the other a advantage of a light like this is all the off to the side so doesn’t have to be directly over the part is if you have an issue with the people totally directly or camera directly over the part I found same thing here all this was a plastic all case I guess CNN omega-3 wasn’t around this for something that clearly can see this is a coaxial Rayfield ringlike or reflection obviously you can see the source there flight it was use again a linear array off often side in assessing this is the geometry are used to tell all the best meaning fancy just has to be law fangled it majority debt latest theme of surface bouncing away the camera does not see all but what it does see is what also thrown onion site comes back out gators of a stamped date: all recessed know all the metal part all exterior flat curve who knows when those governments to deal with all sorry start out with your your your ever present right field spotlight and do you know if you can see there’s a code there is tough to get much out of it me we can read it maybe we couldn’t resist my probably struggle with that all again we have the issue we don’t have good quality with a controller lady words is not sample appropriately separate areas the top ways regard to the bottom we try to compromise in the middle and you can see what happened last them through somebody’s other choices are gone from a very small solid angle tool of higher solid angle ringlike all again compromise in terms of getting the background lighting correct all and you can see now okay yet back and read that day this system may still struggle a little so a scrollable further our rustic limelight and low angle and all you can see that what happened was all it effectively allowed versatile services sure what but the vertical surfaces and the other services business social that should tell you pretty much what you need to do in terms of all of the universe of ringlike okay and this is where a circular dark filtering light is a necessity cars you have to all look at the entire surface all angles and you can see there that we got a good clean image is consistent and we can also read little bit of a code up there at the top as well so we equate surface glare all we change the geometry back all 3-D spatial arrangement of the light a the interactive service reviewer can service our home we strolled the overwhelming we use polarization filters all that’s really the least preferred but is it it can be done and now I should probably take a little polarization all in general that’s going to be discussed in more detail and all certainly in advance classes all but really what it wills on trees you got two pieces of polarization film in the optical path the first one is all between the light and sample the second was between the sample and the camera okay and are both the same material was just known the polarizer once known as an analyzer and thought you doing these are just preferring a particular vibration direction to get back to sample the camera from samples of the camera of the said Odyssey has the advantage of blocking layer to some extent there is an example I set up all using polarizers on a flat surface and will polarizers you can seriously bad reflection back on the flat spots to applying polarizer you can see the big differences here are really boiled down to roll its it’s clear now so we took care that glare on a flat surface using while at three outs that’s wonderful there are caveats all in order to do that because it’s usually polarizer your your preferring a certain direction and which means your your cutting on your intensity of else’s sample take is on the same approximate all contrast in intensity on its second with polarizers actually had open f-stop times to NSF tops and that’s a tremendous amount of intensity loss to do that so if you have had overhead to do that’s a perfectly acceptable choice all what if you don’t then maybe need to think of another way to do it in my first approach typically if someone says are going to use polarization for glare control I typically will say Willis the staple of committee look at the geometry secretly changed geometry so and so here’s another sample all I disses of the Jell-O K and what we did here was all issues of a standard ringlike will polarizers things you got a pretty bad reflective hotspot there in a middle we take the same sample with polarizers UCI coming up pretty well I did all but you will notice also that there are as a little bit of reflectivity there in the center and her surface and so there’s no way to dial out all over the reflective reflectivity financing because of perseverance and have some spot where you can get some reflection back is just physics and so my approach in this case for sure if that is an issue maybe it isn’t but if it is certainly I would want to all change my geometry okay so all we did here was the effectively use a ringlike off axis day and a good rule saw Ms. if you’ve got are of a cylindrical surface you want to handle late coming in this way down the long axis is supposed to coming across and it’s always a good way to keep that minus oh we did here and so is this case now Melissa Powell rotated 90° it doesn’t really make any difference all you very good clean image and you won’t have any glare so again if you have the luxury of changing that that’s good on some all situations stolen themselves to that particularly if you haven’t had a chance to developer the luxury of developing application from scratch in a cage your your sort of stuck with all having to come in after the fact and sometimes players Asian is this the best you can illustrate a call like use polarization you envision when I scan all is to take advantage of how it interacts with materials okay so sixpack plastic ring carrier for example here okay to look at it under backlight without polarizers it’s pretty clear that all must seceder pretty boring okay sister light shines through him however if I polarizers and there you can see the difference right away at and so what were really doing here is for polarizing light for particular vibration direction and music go through the sample is that sample is this different controlling is going to reflect over her developed of diffuse a later whatever the case may be Frank light differently and so frankly differently so all you get a change you get it you give an image so I tend to want use polarization in this method might seem as our example all 3-D reflection geometry once again all it’s all about that 3-D relationship that I’ve got a sample all coaxial light of this have been disowned her was a in fuel fell for it was we descend to recode on the surface so wasn’t that difficult a situation by Basilica of the different ways to handle the geometry here all so if you take a look display all straight now mounting kind of figure what happen you to pretty bad hotspot reflection are here okay all you have is the includes the sample service altogether so there’s not much you can do and so you know your chain geometry where your choices if you can’t change lights where your choices loss axis and one of two ways welfare axis this way over this way you will philistine both will show you what they look like some people bought off axis toward the back for example in other words the late is shining on an perpendicular all to the long axis of the cylinder you might expect what you see is something like this all is probably acceptable if caveat that all the light the sample space is presented exactly as it should be all a time investment or his cases we well know so this Atlanta be rotated just slightly then you have an issue there okay see you simply not going to roll and include some of the day so once again on we go off axis one direction must try moving off axis on another direction case number words parallel the long axis case might expect since I sort of hinted that earlier all this is a sort of image you would be expected maybe get in this case pencils was much cleaner all that sample can be rotated quite a bit and you still have a pretty clean image usable image they’re all here on this case had a light that will relatively close to the part all I think that if all you couldn’t get your plate is close to the part-time typically your best choices to get a bigger drive okay so basically just get out of more powerful light from a longer distance and in fact I would say that is probably even a better image for whatever reason Those you have that option is always worthwhile to change the geometry to us something that color wavelength of about one you ways to change contrast is with color and there are two rules of Tom with her little while color will appear to sort of demonstrate that and the warm colors are on the last red orange and yellow and the Google is honorary a violent blue-green I have them labeled so when you print this out black and white you can still actually tell what’s life all but there are two rules of tone with respect to using color to change contrast and light colors for families tend to lighten and obviously in there and the adverse case A colors or family standard are in solar words all the case of a white families a red light is going to make a red object appear brighter relative to the background and vice versa with all rid light green feature is so we can take advantage of this to change our contrast all so call again here’s here’s a sample and example all color wheel on the right you can see that this is an envelope on sex was an envelope with a stamp on okay it’s imprinted stamp all and is not at text in the upper right hand corner and it’s something else that all so what I did is I know through some red light at three typical all annual notice that the G is not much there there a sure user is a stamp their so you might wonder what what’s the land all bottom line is that all the red from the light was reflecting off the red stamp okay and we have basically no contrast with respect to the background so completely wiped out and filled it under white light this is actually what your switch you should be seen question is all Ms. White necessarily the best choice all could be depending on your situation all multiple samples coming down align we have no control over what colors coming next ABY is a good choice for sheep and you use a color camera of course however can we do better job with her contrast if we needed to so obviously will become playhouse mother colors here and we’ve got blue know right now you’ll notice that the Lula little bit more contrasty all I may think that all might expect that with respect to. Whether the way all day because again it’s opposite on the wheel and more or less okay the blue and the red are somewhat absent on the Middle East different colored families all is not quite as its the contrast is better but of Masters mates we can do yet so obviously if you go straight across where you get the most the maximum for your own bang for your buck and in this case of course it was green so as the best interest I think the important caveats remember with this particular situation is all you’ve got to consider what that lights doing not only your sample but also the background and white light all I was you will contrast all colors as I said it could be compromised what you’re trying to do so this monkey tools in my palm disappear essentially for for reference purposes but all different samples do respond differently to different wavelengths and we know that in some cases all it’s useful to the work all different colors different wavelengths so obviously if you’ve got a fluorescent source that you really discover to be a good choice all my experience with our broker for example all all tire rubber for example red light doesn’t work at all and for some reason it just sucks the life right out of it and so nor yellow world white light sometimes even a blue sometimes depending on the type of material will be better for example all again and the only problems as I is a stressed earlier all you want to consider all monochrome sources say that where you can use a vessel through the block of DMV just pass it particularly and I also mentioned letter beneficiaries strolling red light snow madness earlier to the trace either so-so review and summarize here in terms of what we thought what we’ve done and I think the goal here is to help you consider everything that you have in your chest here to come up with a solution and so I mentioned I wanted part of a standard lighting method Mrs. was closest I can come to a cookbook on what I would say is this some start by determining your features of interest I know this sounds self apparent but the bottom line use of supervisor bridges sample says inspectors should better be asked him okay what am I inspected with my looking for what’s important what are we trying to do and get as much information as you can so you start there figure out the features of interest I I always myself I started analyzing part presentation because again is like that stressed earlier all situations were like you have a dome light have to be sure that you are all your can put the dome light in that place and its workforce so tantalize your access all service characteristics I usually go next with K is in the reflective surface all Ms. their texture involved all what’s a contrast like can type today in can I boost the contrast between the background Annas and sample what’s going on with the surfaces of Flanders occur in all finally got have some awareness of the late types the applications techniques members you need to understand how the geometry is over the Almighty do that have a good background on what brightfield is you versus diffuse lighting all verses all backlighting okay for example ethanol all and then I start writing within the cornerstone issues is a said before I think one of the that the issues with Waterstone is where life were to wait till all is that I usually start with the geometry and that’s variables pane menu sample and then emulate issues sometimes it’s obvious to me is some a customer calls and visits of before we have problems sunlight high know right away that I’ve got to all work on controlling him issues but they doesn’t assume even ignore everything else so you can keep that my adult final summary Serling conclusions here all it is I’ve been saying before I is important that you develop your lighting solution very early in the process don’t wait until okay got my camera picked out I’ve got mine sample handling picked out all she know I need to work on lady 90 to work on lensing one get those involved right away because as you can see here there a lot of caveats for properly all again lighting techniques the terminals don’t forget your four cornerstones all over you about like the ambient light in terms light source intensity comparisons of it was that the two to consider apples and apples all I think a better approach rather than asking for an intensity value would be to just simply get the light and try it as the best solution triteness of work for your application will forget about you camera sensitivity that’s a critical issue sometimes as well all monochrome for high accuracy gauging know that Spencer will a solid wind remember but don’t forget that your late may interact quite differently with your samples okay on textures colors compositions all play a factor in what what’s best developed for and say you know make the lighting solution as robust as you possibly can and will oftentimes means getting as many samples as you can all and running them over and over until you’re sure you’ve covered everything you need to cover all and then odds are she got the right lighting your solution is going to be robust and obviously of you more help call lighting professional in their manuals out there thank you that concludes session to basically verse always got a broadband source you got Nero banner my

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