Normal maps from photo test
So I decided to try it out on an old Morgan dollar I have handy. Rc high pass filter After a few hours messing around in Photoshop, I tossed the results onto a coin model and got this. Inductor high pass filter I’m amazed at the results.
High pass filter phase shift The scratches and dings you see are all present on the original coin.
I used a BR30 type lamp as my light source. High pass filter rc It obviates the need for a diffuser, and I also used an LED version to keep the heat down. High pass filter capacitor Warm or cool white doesn’t matter, just balance your camera to match and you’ll be fine. High pass filter design pdf A macro lens is a huge plus for big, detailed results; I used a Canon 100mm macro on a t1i crop cam for this test.
I suspect that coins that are too new or polished/shiny might not work well with this method (proof and “specimen” coins). High pass filter kit Coins that are really dirty and/or beat up might not work so well either. High pass audio filter calculator Uncirculated coins with a silvery/matte finish, such as Silver Eagles or newish coins from circulation, and lightly circulated coins should work great. High pass filter ableton As you’ll be desaturating during this process, copper and gold colored coins will work fine too (though two-tone coins like Euros or Canadian toonies will need the color restored in surfacing and rendering).
1. High pass filter audacity In addition to the four direction shots, do a fifth shot with your light source as close to the camera as possible, to get a “flat” shot with no directionality. High pass filter differentiator That goes into your Blue channel. High pass filter with gain Once it’s in, adjust it (Blue channel only) with Curves so that the flat areas are solid white (255) and the edges get no darker than 128.
2. R c high pass filter calculator Once done with the tutorial method, massage the R and G channels of your flattened image with Curves until the fields of the coin (where there are no design elements, the “background”) are around value 128. High pass filter cutoff frequency calculator This improves the accuracy of the overall result. Cutoff frequency high pass filter If you are shooting new coins, you’ll get “mint sheen” specular hits in addition to unevenness of the levels in the fields of the coin from lighting; for that, use Lasso in Photoshop to select the brighter or darker on the source photos, generously Feather the selection, and then Curves to push them to 128.
The surface I’m using is just the normal map, 42% Reflection, 20% Diffuse, and Cook-Torrance specular for the metallic look (one light in scene). High pass filter circuit analysis There’s a lot I plan to do for further realism, including ambient occlusion to simulate tarnishing, and some toning as well.
The following is a tutorial for the workflow I developed for doing coin normal maps. Rc high pass filter as differentiator This will work for extracting a normal map from any small object with raised surface details, like coins. Inverting high pass filter This is a big one!
1. Low pass filter and high pass filter This works best with coins that have at least some “diffuse” shading, in LW shader-speak. High pass filter design tool Swampy’s pound coin above would work great. High pass filter tutorial Lightly to medium-circulated coins work best, though if you are adept with Photoshop you can still get usable results from relatively clean, shiny coins. High pass filter guitar pedal The trick there is to use a large diffused lightsource such as a BR30 style floodlight. Application of high pass filter Use an LED or fluorescent version to avoid dealing with all the heat.
First, read through the original tutorial here . High pass filter for tweeter Especially pay attention to using a diffused light source — ideally, very large/wide by comparison to your subject.
My tutorial focusses on the Photoshop workflow, including a few elements that were not in the original tutorial. High pass filter sharpening I’m being deliberately picky here to get the most realistic results possible without using precise mathematics and expensive rigging. High pass filter for vocals In reality, you can skip or fudge quite a few steps here and there and still get nice results. Transfer function of high pass filter The Morgan dollar map I used in the earlier test render was done less exactly than below, and still works well.
Before you start, Google around for some examples of normal maps. High pass filter frequency Load them into your paint program and examine the three channels independently to familiarize yourself with how they look. High pass filter calculator op amp The main benefit of doing this is that you’ll be better equipped to spot issues during the process, *and* while you are doing the photography, you’ll have an idea of what the raw shots should look like to give you the best head start.
A DSLR with a macro lens — in my case, a Canon t1i with 100m f2.8 macro lens — gives the best results, over 2500 pixels per side. High pass filter eq Ideally, you want to shoot RAW as well, to maximize the available bit depth and dynamic range.
Expose for the brightest exposure possible **without** clipping the highlights. High pass filter uses Use your highlight/clipping warnings if your camera has them! This is a “data acquisition” type of shooting, you want all the data without any loss. High pass filter dc offset You want the full range of RGB values as possible without any 255’s.
When setting up your photo apparatus, try to get the coin to be as close to parallel to the film/sensor plane as possible, and try to fill the frame. Difference between high pass filter and low pass filter Especially when using a macro lens, the shallow depth of field might put some parts out of focus. High pass filter photoshop Try to use as small an aperture as possible, but don’t go below f16 or f11 if you are using a macro lens and shooting for superhigh resolution. High pass filter phase I used a tripod with a center “elevator” to move up and down for different coin sizes.
If you have a cable release or remote, use it! You’ll minimize registration headaches later due to the camera being bumped out of alignment with previous shots. High pass filter 2nd order At these scales, we *are* dealing with errors at the level of hundreds of micrometers. High pass filter transfer function magnitude Canon users: Magic Lantern comes in handy for this with it’s proximity sensor trigger, *if* it’s working (the version I have would shut down the camera after every other shot, so I did it the hard way).
Try to shoot in the order from the tutorial: lit from above-left-below-right. Speaker high pass filter OPTIONAL: you can skip the below-left shots and related steps if you really like your initial results, or just want to get some quick and dirty results.
(NOTE: the coin is rotated 45 degrees in the sample pics because I had to work around the tripod legs, which blocked the Below shot. How high pass filter works If you find yourself doing the same, just remember that rotation through this process, and then take it out right at the end before you save final.)
Note: Normal maps can vary by which channel is X or Y, and by their “polarity” (i.e. High pass filter with inductor from which direction the light seems to come). Rc filter high pass Fortunately, the Normal Map node lets you invert channels as needed, so we’re using the specifications from the original tutorial: Red=X (lit from Right) and Green = Y (lit from Below). High pass filter hpf Going forward, all uses of Above/Left/Below/Right implies “lit from”.
3. High pass rc filter Check Registration of the channels to each other in both documents! Especially if you didn’t have a cable release, the camera will likely have moved between exposures.
b) Zoom in to 100%. High pass filter applications Try to be near the middle of the coin image, not the edges, to minimize the effect of any rotational offset. What is a high pass filter Unless you really booted the camera good during shooting (in which case you should have started over), rotational offset should be negligible.
c) Drag and/or Nudge the red channel until it lines up to the Green layer. Transfer function of a high pass filter Here again is where studying some good normal maps will assist you in determining what “looks right”. High pass filter and low pass filter A well-worn coin with scratches on the surface is GREAT for this, you can line up the smallest details.
5. High pass filter low pass filter Remap layers. Transfer function for high pass filter The point of shooting both directions for each axis is twofold: it appears to help mitigate stains by comparison to topical features, it mitigates any cast shadows (unlikely with coins) and also adds additional data which helps “average out” the normal data.
8. High pass filter cutoff frequency Apply High Pass filter to the red and green channels independently (you can do them together if you aren’t being as precise). High pass filter ic Start with the largest value (250) and be sure to click the Preview on and off to make sure that the filter is evening out the coin field without starting to crush the larger elements of the coin design. Rangkaian high pass filter 250 is usually enough, but if you have some stubborn reflections you want to flatten out, you may need to start reducing the threshold.
If your red and green channels didn’t look like “proper” normal maps before, they should be getting really close now. High pass filter logic If your histogram for each channel shows a big spike around middle gray (128), then you’re probably good.
This is the magic step that the original tutorial left out, and which I did not use in my first attempt with the Morgan Dollar. High pass filter image It can be skipped if you don’t need to be so exacting, as you can still get nice results, but this step will go a long way to getting you a good quality *accurate* height map out of Crazybump down the line.
9. 40 hz high pass filter The Blue Channel. High pass filter youtube You might have been wondering about it. Difference between low pass filter and high pass filter This is another step that the original tutorial ignores. High pass filter gain This is because game engines can recalculate the blue channel on the fly from the red and green channels, so most game developers (for whom the tutorial was written) don’t bother with it. High pass filter c code You can shoot a blue channel in photography, as I did for the Morgan dollar, but it’s physically difficult to do (the light needs to occupy the same space as the camera), and not really worth it.
h) Last point: Output 100, Input 100 (it should already be there by default). Sallen key high pass filter calculator If you did your High Pass filter correctly, your histogram in the background should have a nice big center spike evenly balanced around your center point.
The blue channel is effectively a measure of how far the surface normal deviates from vertical. High pass filter garageband Since coins are unlikely to have surface relief that departs more than 45 degrees from flat, I then adjust the result with Levels to ensure all values are above 127 (Output levels 128,255).
a) Using the circular selection tool, select the coin face. Guitar high pass filter You want to be tight enough to trim off the edge reeding, but include most of the edge face.
Optional extra steps are to import the normal map into Crazybump, if you have it. High pass filter circuit design The main goal here is to derive a good grayscale height map. Digital high pass filter You need it for two purposes:
This is where all that extra work to get close to 128 in the flat fields of the coin pays off; if you don’t HighPass it, you’ll have large areas of variation which Crazybump turns into massive hills and valleys you don’t want. High pass filter design in matlab In fact you’ll get these even if you did all this exactly as I did, but they’ll be more manageable.
1. High pass filter for speakers For your displacement map, adjust Depth until you see no clipped whites or blacks, then send it to Photoshop and HighPass it there. Corner frequency high pass filter Similar to before, adjust the High Pass filter as low as possible without starting to crush or even invert large details (like the head on the coin obverse). High pass filter experiment You will likely end up having to add a Screen layer and paint some white to “pull up” some areas. High pass filter calculator passive Ideally you’ll end up with a good approximate heightfield that you can use with Curves to obtain a decent mask for the raised features.