Optimizing my search technique for picking fine micro-matrix

[digit]

I enjoy picking through micro-matrix gravel from a number of localities (though most of my stock comes from places I've been able to collect here in Florida). I'm currently working on a project to try to find interesting micro-chondrichthyan teeth in micro-matrix from Florida and some of the teeth I'm looking for are on the order of a millimeter and finding ways to pick through large amounts of very fine micro-matrix to look for my rare tiny treasures has been a long and evolving process.

 

I've previously written about my first optimization in picking micro-matrix--classifying. Rather than look through bulk micro-matrix, I purchased a set of stackable sifting screens with mesh sizes from 1/2" down to 1/100" (though the 1/50", 1/70" and 1/100" don't get as much use as the others). This has been a big help in sorting the bulk micro-matrix into different size classes which makes picking more efficient. Certain types of fossils tend to show up in different size classes and so you can more easily focus on the types of fossils you expect to find in the different size classes. Having uniform size material also helps to more evenly spread the material out while picking so that larger diameter material does not obscure smaller items. This was my posting from a few years back detailing my picking method at that point in time.

 

 

I've been picking larger volumes of micro-matrix lately looking for some rarer finds. I've given up my two color-coded cup method of going through a cupful of matrix by pouring unsearched micro-matrix out of a blue plastic Solo cup and pouring the discarded searched micro-matrix into a similar but red cup. Given the larger amount of material I'm now processing, I dump my paper plate directly into a small, cheap, flexible plastic bucket I picked up for a dollar each at a discount store.

 

I still use my 5X large diameter floor-standing magnifying lens with two banks of LEDs for lighting as the most efficient way of picking through the larger material held back by the 1/8" and 1/12" sifting screens. I have the search image pretty well burned into my gray matter by this time and can quickly spot interesting fossils while looking through this large well-lit lens. Having to look down through the lens does have the drawback that it wears on the neck muscles and prolonged picking generally leads to a bit of neck strain and occasionally a bit of a headache (but then Excedrin has always been part of my fossil hunting gear). 

 

   

 

The finer 1/20" and very fine 1/30" micro-matrix (what I've been humorously calling nano-matrix) cannot really be reliably seen well enough to efficiently pick through using this lighted lens. My various solutions to the problem of picking nano-matrix have ranges from high tech to low tech. I started with an inexpensive "digital microscope" which is little more than a small USB digital video camera with a ring of LED lights and a stand.

 

 

My paper plate that I use for picking would not easily fit on top of the small stand provided and so I improvised with PVC. With a few connectors and lengths of 3/4" diameter PVC tubing I managed to create a simple stand that would allow the plate to be positioned properly under the camera where it could be focused on the matrix. The biggest drawback with this setup was that the "live" video feed that I could view on my computer monitor was being fed with video data through the USB port. I'm not sure if this was the older USB 2.0 or the much faster USB 3.0 but the bandwidth was still not high enough to present a realtime feed of what was on my plate under the scope. Moving material around with my little dental plate and trying to coordinate my movements by looking at the computer screen was a total failure. The slow frame rate and delay made this method unworkable. This scope mostly views the dark insides of a filing cabinet drawer to the side of my desk in my office.

 

A lower tech approach actually succeeded a bit better but still was ineffective for more lengthy sessions of picking micro-matrix. I have a few photographers loupes back from the days of pre-digital (chemical) photography when slides were more than just something found at a kid's playground. I have a 4X and a 10X loupe. I've found that by looking backwards through a loupe (placing my eye where the slide would have been) that I can use these loupes to get a good close-up view of the details of fossils and other tiny items. I experimented using holding a loupe over one eye while holding my head down near my plate of micro-matrix so that the line of micro-matrix is at the proper focal point. This only allows one hand free and as you can expect becomes uncomfortable and annoying in a remarkably short period of time. This led me to look for a similar technique that was more hands-free.

 

 

It wasn't too difficult to find an inexpensive pair of glasses frames with flip down lenses for each eye. The product came with a number of different magnification options for the lenses. Using a 10X lens meant that the focal plane was not much more than an inch in front of the lens and so any hopes of binocular vision through these glasses was soon extinguished. There was no way of placing an object an inch in front of one lens so that it could be seen through the other. It wasn't too difficult to pop off one of the lens mounts from one side of the glasses to reduce the weight of the setup (the glasses don't have very curved arms and tend to slide down my nose while wearing them looking down). In order to not be bent over with my nose an inch from my picking plate (an uncomfortable pose to keep for very long), I raised the viewing platform to my eye level while sitting in my office chair. This necessitated pulling a number of large books from the shelves in my library (I have many thick books) and stacking them on my desk to raise the level of the paper plate I use for picking. I used my large lens floor-standing magnifier but only as a light source. It too needed to be raised up as the vertical adjustment for this has a limited range. A copier paper box was enough to bring the light source to the proper level. With this odd looking setup I was able to pick through the 1/20" and 1/30" material while getting a good view of the detail of the tiny bits passing inches in front of my eye. The big downside to this humorous setup was that prolonged viewing of my bright plate of nano-matrix through only one eye focusing so close tended to mess up my vision. Taking a break from this method of picking and removing the glasses while making a trip to fill a water glass or otherwise stretch out left me a bit "snow blind" in one eye where I'd been viewing the brightly lit white plate scattered with bits of matrix. Focusing right in front of your face with one eye tends to keep both eyes from focusing in unison for a disturbingly long period as well. While this worked--it was not a good long term solution going forward.

 

I realized that I'd need a binocular solution and possibly something that would comfortable for longer spells of picking. I started looking at binocular microscopes. There are two basic styles of microscopes (not counting scanning electron microscopes): backlit compound microscopes for viewing slides and top-lit dissecting microscopes for viewing 3D objects. Obviously, the latter is what I started looking at for viewing fossils. The advantage of a nice binocular setup is that the eye pieces are well above the subject and generally angled at 45 degrees so that you are not looking straight down which would become uncomfortable over time. I noticed that the higher end scopes were trinocular in that they included a third port where a camera could be attached. In the lower end scopes you usually need to switch between the binocular eyepieces and the camera port (sometimes requiring refocusing after the switch). The highest end models allow simultaneous viewing (and focusing) through the binocular eyepieces and the trinocular camera port.

 

I then considered that viewing the micro-matrix through the high-eyepoint binocular eyepieces would be an improvement over having my nose to the plate and looking through one eye but that being able to see live video through the trinocular camera port might be even better. Many of the digital cameras sold as attachments connect to what is called a C-mount on the trinocular port. There are a wide variety of resolutions of cameras that can be purchased but most of them transmit video through a USB connector. The faster USB 3.0 models claimed to be able to push video fast enough to support 50 or 60 frames per second but at reduced resolution (like 640 x 480 pixels). Then I spotted something that intrigued me--a digital camera with an HDMI output!

 

This changed my thinking and the trajectory of my online shopping. I started looking at microscope packages that contained HDMI cameras. What's the big deal about HDMI? A camera with an HDMI output is capable of sending out realtime high-definition video directly to a (HDMI-equipped) monitor--by passing the computer completely. This removed the bandwidth bottleneck that resulted in slower frame rates or reduced resolution but also made it so the video could not be processed and stored by the computer--something I had no need for. This new tack of online research led me to an entirely different class of microscopes. It seems that there are many interesting professions that all require seeing something small magnified greatly in real time so that it can be worked on--fabricating dentures and crowns for dentistry, watch construction and repair, jewelry making, smartphone repair, printed circuit board diagnosis and repair. Though none of the industrial digital microscopes I saw with my refocused shopping parameters mentioned picking micro-fossils, I knew I was on the right track with functionally similar tasks being solved by these packages.

 

One of the companies that seems to have a bit of a lock on simple microscopes with digital cameras (and sometimes attached monitors) for industrial use is a Chinese company called Hayear. They have a wide variety of products for all sorts of industrial use. The prices are very inexpensive (compared to the higher end trinocular scopes that I was looking at previously) but shipping costs from China were a substantial addition (in some cases nearly half the cost of the scope itself). Shipping from China to the USA is also less than speedy involving weeks to months for arrival. I wondered if this company had an online store on Amazon.com and was happy to see that they did. They have a reduced set of products that they sell through that marketplace and the cost of shipment is build into the higher prices there (though not as high as buying a single scope--likely due to bulk shipping of products). The nice thing is that 2-day delivery with Amazon Prime is much more instantly gratifying than 2-month shipping with a direct purchase. The model I found for sale looked to have what I needed and was a mere fraction of what I was looking to spend on a trinocular scope with the addition of an HDMI camera and a LED ring light for even illumination.

 

 

It only took me a few minutes to setup. There are no instructions on how to assemble but if you look at the photo (above) and the parts available in the box, it is a pretty easy puzzle to piece together. The package does not contain an HDMI cable. These tend to be expensive cables and so they've opted not to include one in case you are not making use of the HDMI output (there is also a USB output and a memory card slot where photos or videos can be saved). I robbed an HDMI cable from my DVD player (not used as much these days with streaming) and I was plugged into one of the large monitors on my desktop computer (I use large dual screens). It didn't take very long at all to get things adjusted for best use. One of the concerns that was pushing me away from the more expensive trinocular scopes was the magnification range. I want a relatively wide viewing area with a low actual optical magnification as I need to be able to see a number of granules of micro-matrix at the same time and only need to zoom into a single item if it looks interesting. Theo objective magnification of this setup is only 0.7 - 4.5X but by the time the image is picked up on the digital camera and displayed on a large computer screen the effective magnification is more like 20 - 400X.

 

I was instantly impressed by the snappy realtime video response provided by the HDMI. It was worlds better than I was getting with the Celestron that was futilely trying to push video through a USB cable. I noticed that the high contrast provided by my white paper plate background made the darker phosphatic-black matrix and fossils a bit difficult to see but I was able to override the exposure using the small camera remote control included in the package (there are similar buttons on the back of the square camera block as well). I pushed up the exposure +2.0 stops and this made the black gravel (and fossils) show up better (by over exposing the plate).

 

I found it very easy to coordinate moving the plate under the camera to bring new matrix into view and within just a few minutes I found one of the rarities I had been looking for that was hiding in this 1/20" size-class nano-matrix--a minute Scyliorhinidae (Catshark) tooth just over a millimeter in width. Here's a quick picture of my computer screen with my little point and shoot camera which will give you a feeling of what I see while picking 1/20" nano-matrix with this new technology/technique.

 

 

I've recently gone further to solve my high contrast issue. I looked at finding gray paper plates (maybe for someone's retirement party ) but was unable to locate any. I had the bright idea of spray painting one of my existing picking paper plates with some flat battleship-gray spray paint. Regardless of how flat the finish looks under normal light, it is still quite shiny when illuminated by 144 LEDs. I had a sheet of thick (construction) paper that I often used for a neutral gray background while photographing micro-fossils and I made a test by putting a sheet of white paper over part of the gray paper and placing some micro-matrix across the edge of these two backgrounds. Under the scope I could easily demonstrate that the reduced brightness of the background resulted in a much better view of the little bits of matrix. A bowl of the appropriate size, a pen, and a pair of scissors were all I needed to cut out a gray circle that I glued to the flat central base of my paper plate. I no longer had to crank the exposure up to result in well exposed micro-matrix bits on the more neutral brightness background.

 

The last optimization that I added to my process yesterday was in the placement of the circular line of micro-matrix that I spread along just inside of the raised rim on the edge of the paper plate. The field of view is still rather narrow through the scope and spreading a line of matrix wider than its field of view (easy to do when pouring out of a plastic Solo cup) meant that I had to move the plate side to side while following the line along the plate as I rotated it. I have a small plastic squeeze bottle with a tapered opening around 1/8" and by filling the bottle with my fine nano-matrix, I'm able to spread a nice continuous line around the perimeter of the plate. A few taps on the plate settles the long line of matrix so that the pieces are not stacking upon each which would make it difficult to see all the bits without manipulation with my dental pick.

 

I can now quickly and efficiently spread out a line of nano-matrix about 90% around the plate (leaving a gap so I know where I start and end). I can position the line of matrix under the scope's optics and see it clearly focused and lit on my computer screen. With the tips of my fingers on two hands I can rotate the plate (like turning a steering wheel) to bring successive portions of the curved line of matrix into view. When I see a bit I'd like to pick out, I use my curved metal dental pick to manipulate the surrounding matrix away from the bit I'm interested in so that it may be easily picked up and transferred to where I wish to store it. Through all of this I'm no longer bent over a magnifying lens or looking like some sort of cheap cyborg with a 10X magnifier propped over one eye and my nose buried into a paper plate. I can sit back comfortably in my desk chair and see in glorious detail as the line of nano-matrix is displayed at eye-easing magnification on my computer screen.

 

I'll never admit that I played with my new toy setup yesterday and picked through a large amount of the fine 1/20" (and a bit of 1/30") nano-matrix for over 12 hours yesterday--and did it without ending up with sore muscles.

 

 

I wrote this because I hoped my journey for the most optimal method of picking really fine nano-matrix might be of help to any others who might be doing something similar.

 

 

Cheers.

 

-Ken

 

 

 

[Tidgy's Dad]

Very comprehensive.

[digit]

That's my style--in spades!!

 

It's been a learning process and I'm now extremely pleased at the ease and comfort of the method and tools I've finally arrived at. Knowledge is best when shared and so I would be glad if I've somehow helped others in any way who are doing similar activities.

 

 

Cheers.

 

-Ken

[snolly50]

Ken, wonderful to read about your quest for a practical micro hunt solution. In honor of your success and in full appreciation of the fun of discovery involved in micro peeping; here is an old post of a bit of doggerel.

 

 

[digit]

Aye, that was a great collection of doggerel that would have made Shakespeare weep! (Just don't ask why...)

 

It was indeed the quest for a Cookiecutter Shark (Isistius triangulus) tooth that was my introduction into the realm of micro-fossils. Since then I've picked my way through micro-matrix from a number of sources and localities and enjoyed the excitement that comes from spotting a tiny treasure among the granules after a lengthy search. My chiropractor may not be as happy as my is neck with this new method of picking micro-matrix--heck, the scope may pay for itself in reduced medical bills.

 

 

Cheers.

 

-Ken

[digit]

I've been having fun with my new camera-microscope and it has been very useful for picking through the finer micro-matrix that I just can't see as clearly with my big floor-mount magnifier (shown above). It's taken me several more weeks of picking through Cookiecutter Creek micro-matrix to find another Catshark (Scyliorhinidae) tooth. This one is a nice large specimen with reasonably complete side cusps (which are frequently damaged or missing in many specimens). Though this one was found (last night) picking through the larger 1/12"+ size class material using my lower tech magnifier, I decided to take advantage of the digital camera in my new microscope for imaging. I've been trying to get photos of these tiny micros with a 100 mm macro lens for my Canon 5D but even with the higher resolution of that camera, the tiny size of the photo subject has made for disappointing imagery. I've picked up some diopters that can be used to increase the magnification but the image quality suffers.

 

 

I downloaded the imaging software package for this Hayear digital camera and figured my way around the software. While the user manual is uncharacteristically well translated from the original Chinese, it is sadly short and lacking in content. Thankfully, the software only took a little bit of experimentation to deduce the user interface and how to make it do what I wanted it to do. Before long I was able to shoot a stack of images with the focal plane manually adjusted just a tiny amount between successive images. I fed these stacks of photos to my Helicon focus stacking software. I had not used this software in a few months and I decided to download the available update and I'm glad I did. The new software is exceedingly quicker at combining the images into a single high depth of field image. Here are a couple of images showing reasonably impressive detail of this new find:

 

         

 

Imaging this tooth might not sound like much of a feat to require such hardware and software but keep in mind this isn't a meg tooth (or even an auriculatus which it more resembles) but a tiny little thing. I figured out how to use the measurement functionality included in the imaging software. To calibrate distances in these images you first need a tiny ruler to use as a scale. I have a nice plastic scale precisely marked in inches and millimeters. I used the calibration functionality to measure how many pixels wide (at the given magnification) by dragging out a line spanning precisely 5 mm on my scale. Using this calibration, the software was able to calculate very precise measurements of other dimensions as shown below overlaid upon this specimen:

 

 

So this little Catshark tooth is just 3.2 mm wide across the widest part of the root and a little under 3.5 mm from the tip of the crown to the base of the root. You can see from the single image above that without photo stacking the depth of field is maddeningly narrow resulting in only select portions of the specimen being seen in focus at any one time. I'm quite pleased with both the image capture software for the microscope camera as well as the new version of Helicon Focus software which continues to get better and better. Anybody with specific questions on my software or hardware setup can drop me a PM if they wish to know more details.

 

Cheers.

 

-Ken