Remote Measurement of New World Primates
by Michael Knuepfel and Arturo Vidich
The following summarizes our research project for Wildlife Observation Tools, Spring 2010, an ITP/Anthropology course co-taught by Tom Igoe (ITP) and Anthony DiFiore (Anthropology):
The semester long course was broken roughly into two parts. During the first half of the class students were introduced to Prof. DiFiore's work along with some of the challenges that exist during his time tracking monkeys in the field. For the second half of the class, students broke up into groups to independently research specific technology based projects that could help Prof. DiFiore with his field work. Based on Prof. DiFiore's priorities, student interest and preliminary research performed by Tom Igoe and other ITP Students a semester earlier, the class broke into 5 groups:
Database Group - Students researched and implemented an online database for storing observational field data.
Camera Traps - This group looked into ways for combining cheap Canon Cameras, PIR sensors, and the Canon Hack Development Kit for inexpensive, customizable camera traps.
Custom Collars - This group performed a broad range of feasibility tests for producing custom tracking collar hardware. Topics for research included: collar materials, battery life, weatherproofing, and alternatives to radio tracking (xBees, RFID, GPS).
Using smartphones for data Collection - Students surveyed a number of options for replacing outdated Palm PDAs with smart-phones for field data collection. This led them to test a customizable data collection platform on Android.
Remote Measurement - Laser Tele-Metrics
The goal of our research project was to build a DSLR camera rig that could remotely measure morphological traits of monkeys in the Tiputini Biodiversity Station, Orellana, Ecuador, without the need to continuously dart and capture individuals. The camera rig consists of three parallel lasers mounted to a digital camera. Parallel lasers will project a uniform dot pattern onto the monkeys, regardless of the distance between the camera and the subject (up to a certain point). By taking a digital photo of the laser dot pattern projected onto a monkey, we could later use imaging software like Photoshop to compare the size of an individual’s features to the known scale laser dot pattern.
Capturing monkeys in the field is dangerous for the monkeys, may disrupt their social behavior and is time consuming and difficult to do. Additionally, having reliable morphological data is useful in understanding the growth and development of individuals in the wild. During our time in the jungle, it took us 6 days of active tracking to capture a woolly monkey. We were able to sight and remotely measure monkeys our first day in the field.
Phase 1: Research
We designed our camera rig based on two research papers that also used the parallel laser technique to remotely measure wildlife. One paper (BERGERON, 2006) focused on the measure the length of ram horns, the other (ROTHMAN et al, 2008) on tail length in large primates. While both papers show promising results, are full of useful information, and include diagrams and photos, neither include plans to build a usable camera rig with parallel lasers. If we wanted to reproduce the results of these papers, we would have to build and design our own custom camera rig.
Prototype 1: Making the Lasers Parallel
In order for the results of remote measurement to be accurate, it is very important that the lasers stay parallel, even at a great distance (up to 30m-40m). For our first prototype, all we attempted to do was mount two lasers in fixed parallel. After looking at a number of gun sight designs online, we opted for a triangular set screw design, where the laser is floated inside a cylinder with six adjustable set screws holding it in place.
For this prototype we tried a number of threaded inserts and thumb screws, eventually settling on threaded brass inserts and nylon tipped set screws mounted in a triangular pattern around a piece of PVC pipe.
Inserts: McMaster # 99362A300 Set Screws: McMaster # 94115A184
We designed the fixture in Solid Works and cut it out of acrylic using a Universal laser cutter. We mounted the laser tubes so the centers would be exactly 6cm apart. Next, we adjusted the set screws using the hex screwdriver until the laser dots appeared exactly 6cm apart on our test pattern several meters away. Once the lasers appeared parallel at a short distance from the target (10m), we continued to make small tweaks to the alignment as we slowly moved the test pattern away. After about 45 minutes of small adjustments the laser were still parallel at 16m.
A few things that we noticed:
- The round ellipses of the laser dots become large and distorted over a long distance.
- Green lasers may cause damage to the retina, even from indirect exposure (thank you Eric Rosenthal).
- Tightening the set-screws too much can easily damage the housing of the lasers.
- It is difficult to reach some of the set-screws without a longer or shorter hex screwdriver.
- Shooting at a high ISO and using a fast lens makes images brighter, and easier to measure later in Photoshop.
Prototype 2: “The Predator” - Integrating the Camera, 3 Lasers
After finding that it was possible to make the lasers parallel we thought about possible ways to mount the lasers to the camera. In the first design, we had the camera mounted on top of the lasers, and used 1/8 inch thick black acrylic. The acrylic proved to be too thin and flimsy to stay reliably rigid while using the camera. There was too much play between the two elements. We kept the triangular pattern for the lasers in this iteration, but soon realized that while the pattern looked cool and “predator-like”, having a right triangle rather than an equilateral triangle will allow more information to be gleaned from the vertical pair of lasers. With an equilateral triangle the bottom laser was in a 60 degree relationship to the top two.
We decided to make a rig more robust rig with an arrangement more like the Rothman arrangement.
Prototype 3: L-Rig, upgraded electronics, aluminum reinforcements, detachable mounts.
The L-Rig proved to be the most useful iteration of the camera-laser combination. The three lasers were arranged in an L formation, in a right triangle on the left side of the camera. The top laser was 6cm apart from the one directly below it, at the 90 degree angle, and the one to the right was 6cm apart from that one. The acrylic was 1/4 inch thick, sandwiched together using beveled box-joints (http://woodworking.about.com/od/joinery/p/BoxJoints.htm). The base supported both the L with the lasers and the camera, with aluminum brackets to provide structural support and rigidity for the whole rig. The camera was secured to the base using a handy device from B&H photo that allowed us to quickly mount and release the camera from the rig. (http://www.bhphotovideo.com/c/product/511754-REG/Cullmann_CU_40440.html).
We added an extra hole in the base that allowed us to mount the L-Rig on a tripod-- we had to replace the bolt in the tripod foot with a longer 1/4-20 bolt (1/4 inch wide, 20 threads per inch, industry standard for fastening foots to cameras). Lastly we added a momentary switch, in addition to the toggle switch, which would allow us to turn on the lasers for a very short period of time just to take the photos.
Initial Results: Testing on Static Objects, Playing with the Settings & Calibration and Measuring objects
Once we were able to get the camera onto the rig and the lasers aligned, we began testing with a tripod on static objects. We projected the laser pattern onto a roll of tape, our arms, and onto a furry monkey stuffed animal from a distance of 35m. After playing with the camera settings for a little bit, we were able to get decent shots. Using the measurement/scaling tool in Photoshop (CS/4) we compared caliper measurements of the objects with the digital measurements. To our surprise, most of the digital measurements were within a few millimeters of the actual dimensions, even on organic shapes.
Prototype 4: Ruggidization, getting ready for the field.
Given the strong design of the first L-Rig, we did not have to do much more to ruggedize it for the jungle. We constructed a second body out of the same material (1/4” acrylic plexiglass), and flipped around the L component that houses the lasers to position the vertical part closer to the camera lens. This would make it easier to ensure that all three points would be contained within the frame. The main component that required ruggedization was the circuit that provides power to the lasers, and the switches to turn them on and off. We designed a circuit layout in Eagle Cad, etched it onto copper plating using muriatic acid, and soldered the voltage regulator and connectors to the board. After that we hot-glued all exposed electronics to prevent moisture from building up. We did not hot-glue the exposed copper circuitry on the board, but it did not prove to be a problem in the field. After just a few days we noticed some mild corrosion. We used zip-ties to keep the rig together, while allowing access to the interior should we need to replace any electronic components. We purchased various shapes and lengths of hex keys to maneuver the tight spaces, and gain access to the set screws. The L-Rig fit perfectly into the pelican case lent to us by ITP, which prevented the lasers from shifting while we were trudging along in the field. The tripod we used for calibration has X, Y, and Z levels that show when the camera is shooting horizontal into space.
Field Testing in Amazon
Goals and plan:
- Calibrate the lasers
- See how difficult it is to get a margin of error less than Tony’s ~1cm limit
- Find monkeys and get lasers onto them. Take pictures. Measure in Photoshop
- Test the rig in the humidity, lighting conditions, and rugged terrain of the jungle
- Use lasers to measure a sedated monkey and compare those with physical measurements
- Test the rig with vertical surfaces using clinometer and range finder
- Do a distance test to show (at full lens zoom) how many pixels correspond to 6cm at 1 meter increments. Create a graph and a table that illustrates these values
- Judge feasibility of laser metrics for measuring morphological traits of primates in various orientations besides vertical and perpendicular
Summary of time down there:
DAY 1: 7/3/10 - Dinner - Pasta and Cheesy Broccoli
Morning, we calibrated lasers to target, on L-Rig at a distance of 16m, down the hallway on the second floor of the lab. We took several shots at 3200 ISO, with auto-focus, and some at auto ISO. We used the 50-150 Sigma telephoto lens, on the Canon T1i. We measured the distance between red laser dots on the subject using Adobe Photoshop (CS4). In Photoshop we used the "Analysis" menu, and "set measurement scale" to "custom". We then used the measure tool to set the pixel distance between the centers of two of the red laser dots, and assigned them the known value of 6cm. Having the third laser allowed us to double check the initial measurement. This only works when the target is at the same inclination as the rig, and perpendicular to the lasers.
Issues for calibration included moving the lasers horizontally or vertically, tightening set screws on backs of lasers was neglected, getting focus in center of the shot, or on something in the background rather than foreground. Adjusted metering function.
Tried to use video function in T1i with same lens, at 1920x1080 resolution (highest), but couldn't figure out how to export a jpeg from Final Cut or iMovie. Instead we took a screen shot of a relevant frame in the compressed .mov, using in-computer zoom function. The results were less desirable. Mike's wrist measured 6cm wide, but the measurement from the video indicated 7cm. Too much error due to low resolution.
We did some preliminary distance tests, but the images were not always focused on the subject. (see above). We need to do more tests for off-axis subjects (oblique doors, ground to top of post-- about 45˚ incline. We placed the target at a ground distance of about 7m, and a height of 3m (one flight), the angle of inclination was about 30˚. The horizontal lasers were at the correct distance from each other in Photoshop, but the vertical lasers were over by 2mm.
We went to Torre 1 [tower 1] and took some shots of tree branches and dense foliage, but those shots were mostly out of focus and it was difficult to ascertain whether or not the flat surface of branches were perpendicular to the rig.
Tony believes we can figure out the distortion of the fixed distance of the parallel lasers when projected onto a vertical surface using trigonometry.
We saw monkeys, but the rig was not prepared. No lasers on monkeys. Slightly disappointing, but exciting. However, using an 85mm lens, we managed to capture a few photos that would have been usable for measuring knuckles, and facial features.
DAY 2: 7/4/10 Dinner - BBQ chicken and rice
Our goal for today was to compare the actual tape measurements of a darted monkey to laser pictures of the same individual. Tony wanted to collar a woolly monkey with his new GPS collar, so we spent the majority of the day following him and his assistant, Rob, as they attempted to dart an adult monkey.
Soon after breakfast, we re-calibrated the laser rig and packed up all of our gear. Rob used the telemetry equipment to get us oriented towards woolly monkey group G. After about 25 minutes of trail hiking and bushwhacking we located the group. We immediately pulled the laser rig out and started taking pictures. We were able to capture a few usable shots before the monkeys moved out of sight. For the next two hours we followed the group, taking pictures whenever we could. In a moment of rest (at around 12:30 after 4 hours on the trail), we took out the target to check if the lasers were still in alignment. Unfortunately the middle laser was off by a little less than a centimeter. This was a surprise to us because we could not think of any big drops or bumps to the rig. We should check the rig more often! Soon after we re-calibrated (@ <20 m) the monkeys decided to take a nap, and we hunkered down in the rain to wait for activity. Later when we went back to look at the morning photos in photoshop, we noticed that the lasers were already out of alignment for the first monkey shots.
After about an hour, the monkeys continued on their way. We may have had a few opportunities for pictures, but it was too rainy to risk getting the camera wet. It would be nice to have a drybag that fits around the camera body.
Around 1:30 we had lunch, while the monkeys stopped to feed.
For the rest of the afternoon, we had difficulty capturing pictures of the monkeys with the laser rig.
- The sun had come out, making it difficult to see the lasers at the height of the canopy.
- The canopy was backlit by the sun, causing our shots to be very dark. We hope that adjusting the light meter manually on the camera will allow us to get the lighting that we want.
- The monkeys were generally out of view (Behind branches and far away).
- By 5pm, Tony had taken two shots with the dart gun, missing both times. Tony and Rob were surprised by how inactive the monkeys had been.
- On the way back to camp, we saw a pack of currasows, large ground birds. Tomorrow we will try again, also with the 300mm lens.
Day 3: 7/5/10 Dinner - Tacos
We began the day by writing the log for the previous day. We woke up less tired than we thought we'd be. Very good. But still tired.
Tony thought it would be best to stick around camp for the morning and calibrate the lasers. He also needed to work on some GPS stuff, among other things. We set the target at a distance of 40m, and calibrated the lasers. At greater distances, the lasers became more difficult to see, and the dots were more distorted, elliptical. We used the laser range finder provided by Tony to get the distance. However, he said that the margin of error with that instrument is +/- 1m.
We set out at 11am on the Guacamayo trail, and after 30 minutes we located a troupe of Spider monkeys. That particular group had no radio collars. We heard them moving in the trees a few meters off-trail. We pursued them through low trees and hilly terrain. It was muddy. Tony said they were heading to the salt-lick. He took a shot and missed. Right near the salt-lick he took another shot, and we thought it hit a juvenile female. We waited under the tree we thought she was in for about an hour, hoping she would fall. Tony speculated that we didn't actually hit her, or that the drug didn't get in. The rest of the group stayed nearby. At about 1pm we switched to the 300mm lens, which to our surprise ended up working much better. The reason we thought it would not be a great choice was that while testing on the ITP floor in low light conditions, the camera had to be extremely still, on a tripod, to get a clear, sharp shot. The reason we got better shots with the 300mm lens today was three-fold: 1) the newer Canon goes up to 3200 ISO, 2) it was bright and sunny, 3) we removed a UV filer and a polarizing filter that subtracted a fair amount of light. We continued to manually meter the shots to prevent backlighting from creating impenetrable darkness in the foreground, though we still had problems with halos around the monkey's outline, which removes some of the distinct shape when viewed in Photoshop.
After moving on from the salt-lick we heard a screech. Tony had moved ahead and darted a male, but the male fled and hid somewhere in the canopy rather than falling to the ground. Mike and I stayed around the area where Tony thought the monkey was, so he could go back to get his gun and bag. If we heard a crashing sound, we were supposed to identify the direction and keep it. No crashing sound occurred. The rest of the group passed overhead, yielding some great photo and video opportunities, given the low height of the canopy on the ridges. Shortly thereafter, we saw a single Howler monkey moping in a tree, contemplating life, and the three female Spider monkeys of various ages nearby. We pursued the three females for several hundred meters in the hope that we would dart the juvenile, but Tony only had one dart and very little ketamine left. Then he got bitten by a Conga ant (hurts like getting shot, supposedly), and Arturo got stung three times by a wasp, and Mike was a veritable mound of mosquito bites, so we decided to call it a day.
Upon returning to camp, we checked the status of laser calibration and to our surprise they were still fully calibrated at 40m. We looked through our test shots (lasers on trees) and found that those were also still calibrated, within a margin of error of +/- 0.05cm. We found several shots that were very usable, with key body part measurements available, such as wrist length, and clitoral head diameter. We hope to get a full-frontal face tomorrow.
We spoke about the distortion of the laser triangle when shooting at an upward angle, and Tony took out his clinometer. Tomorrow we'll adapt the clinometer to the laser rig so we can get perfect angle readouts to accompany the laser rangefinder and measurements we get using the rig. The clinometer will allow us to account for foreshortening when shooting at an upward angle, according to the Jessica Roth paper (2008).
- go to the tower 1 and get incremental vertical measurements of the target at different heights for testing the clinometer.
- shoot photos of the target at various distances from 10m-40m in increments of 0.3333m. This will allow us to take these photos into Photoshop and establish a table for how many pixels equals 6cm at specific distances. We hypothesis that the values we get will fall on a linear downward slope, or curve, i.e. the closer the target, the more pixels equal 6cm, and vice versa.
Today we learned that cloudy and overcast conditions yield better results in terms of even light. We also measured the same tree branch across three different photos using the pixel-to-centimeter ratio we established in one of them, and found the branch to be the same diameter +/- 0.04cm.
- try the above branch measurement with multiple branches, as in the Roth paper.
Day 4 - 7/6/10 - Dinner Spaghetti
Not much new to report on today. We spent the majority of the day tracking a group of woolly monkeys as they led us in circles, up and down mountains, and across the most difficult terrain we have yet seen. After 7 hours of trekking off trail in dense jungle, we still have not been able to successfully dart and capture a monkey. By the end on the day, even Tony was tired and a bit frustrated. Tomorrow we will try again.
We started the day with a calibration check. Everything seemed to be ok. We also tested out the clinometer and checked the range finder against a tape measured distance. Both appear to be accurate.
We also made a first attempt at correlating distance to a target to the number of pixels. We noticed that the target itself is more accurate than the lasers. We will try this test again later with a more stabilized target.
Tomorrow we will spend more time analyzing the pictures we took today. On first glance it appears that the laser were ~2mm out of alignment at 40m by the end of the day. We are not exactly sure when this happened. More investigation is required.
We captured a few usable monkey-laser pictures today. These include pictures of Adonis, a monkey that has been captured and measured two years ago. He is likely larger now.
Internet has been painfully slow for the past 36 hours. We will continue with the GPS work once we hear pack from Tom.
Day 5 - 7/7/10 - Dinner Chicken and Rice
Went out with Tony in the morning to find group L. Picked up the signal far out on Guacamayo, closed in on the signal but could not locate monkeys. The signal was coming from a monkey named Laverne, an older female. We waited beneath the tree Tony thought the signal was coming from, but no movement or indication there was actually a monkey in the tree for four hours. We waited. Tony finally said, "you guys are free to go back, I'll keep waiting." We set out on Guacamayo and returned to camp by 3pm.
When Tony returned it was nearly dark. He said the group was actually 300m away, and he managed to track them for a while. We decided to wake up early, skip breakfast and see if we could dart one of them.
No laser work, just some basic calibration tests on trees, which were sound.
Day 6 - 7/8/10 - Dinner Beef Stew and Rice
Got up early, like, 5:30am, and got a ride on the boat out to the Anaconda trail, 2.5km away. From there we set out for the Maquisapa trail and quickly got the signal for group L. We followed them, took GPS points and ate breakfast (PB&J) for about two hours. Then they moved into low trees, and Tony managed to take a shot that connected at 8:06am. Arturo was also taking pictures of the monkey with the lasers prior to darting. The monkey fell asleep in the tree and latched on. Tony had us stand underneath her with a sheet to catch her when she fell. He climbed up a different tree and tried to shake her loose, but to no avail. Slowly but surely her limbs disconnected one after another until she was hanging just by her tail. We tried to throw small things at her to loosen her grip but couldn't hit her. Tony was about to dart her again to relax her tail when she came crashing down, bouncing off a small tree, just out of range of our sheet. Head first on the forest floor. But she was okay! Tough monkeys. Soft ground.
Tony wrapped her in the sheet and we followed him to a clearing on the Maquisapa trail so we could process her. Mike prepared the GPS radio collar while Arturo wrote down measurements that Tony was taking. Everything went smoothly, and we got the measurements we needed for comparing to laser measurements later. The GPS radio collar worked and was fitted properly. Once Lina (as we named her) was fully processed she was already becoming more active. We started taking laser measurements from 16m, 18m, and 20m of different body parts (arms, legs, face, etc) that we had just physically measured on her. She was grabbing at every tree and limb she could get her hands, feet and tail on, so we had to cut it a little short. It would have been great if we could have gotten better, more precise information with the time we had, but she was getting feisty. We put her in a recovery bag for 45 minutes while we cleaned up. Then we found her group not far away and released her. She seemed nonplussed but otherwise normal upon release.
After that wonderful experience, Tony let us go back early while he stayed with the group for the rest of the day. When got back we took a few calibration shots, checked the photos and measurements we took of Lina, and called it a day. What a day it had been!
We would have slept through dinner if Tony hadn't woken us up.
Day 7 - 7/9/10 - Steak, Chickpeas and Rice
Went out early to find group L again, took the boat in downpour torrential rain to Anaconda trail again. Once off the boat we realized we didn't have the antenna for the telemetry equipment, and had to walk back to camp to get it. In the pouring rain. We took Lago trail (with the cool suspension bridge).
Once we got back the three of us decided to wait out the rain, which lasted until 1:30pm. We did some more measuring of Lina in the photos, and noticed some difficulty with foreshortening. The papers we have been using as references don't mention this problem so explicitly. For example, the Rothman paper discusses foreshortening as a factor to take into account only due to shooting at an upward angle to the subject-- the tails of the monkeys in that paper are all hanging straight down. Gravity. This means that only a portion of the photos we've taken will yield consistent and admissible measurements, and it will be difficult to know which subjects' body parts are or are not foreshortened. For example, in some of the photos of Lina, her forearm is shorter than others, and only one matches the physical measurement we took. In the images, they all look practically the same! And we found this inconsistency when we measured her face in different shots. Sometimes her face was slightly turned, but that changed the measurement by a few millimeters. The arm parts were off by 1cm to 2.5cm. We need a solution to this.
After the rain abated, we set out again on the Lago trail to group L. We braved a really, really muddy swamp, almost losing boots. Just like the horse in the Neverending Story. We found Lina behaving normally, but couldn't snap a shot. Tony accessed the GPS data very easily with his netbook, but we had to reposition to reprogram it because Lina had moved away. Tony was very, very excited. We set out for camp on the Lago trail again, the number of kilometers for the day topping 10. Before we got to the Lago trail, we had to wade through the swamp again, but a water-logged portion. We almost went into a stream that we couldn't see for all the rest of the water. Water in the boots. Water everywhere. No Kevin Costner.
It got dark right before camp, and it started raining the moment we took off our boots. It wasn't just the water pouring out of them, the clouds opened up. Total rainfall in the last 24 hours was 31cm.
Tomorrow: more calibration over by tower 1, and the canopy walkway! Don't look down.
Measurements of sedated Saki monkey.
Conclusions - What worked and didn't work:
While we weren’t able to measure monkeys with the reliability and accuracy needed for scientific research, we still consider the project a success. Our goals from the outset were:
- To see if we could build a field-testable rig similar to those feature in our source research papers, inexpensively and
- To see if it was even feasible to take usable photos of monkeys with the laser dot pattern (taking into account the various difficulties that go along with fast-moving creatures and the thick jungle foliage).
In order to get this project working to a point where good scientific data could be collected we would have to:
- Create criteria for which photos are usable and which ones aren’t.
- Spend more time comparing manual measurements to laser-metric measurements on the same individual.
- Develop a uniform calibration procedure.
- Find a way to deal with the foreshortening problem.
- One next step would be to partner with a 3D imaging master to see if the problem of foreshortening can be solved by extracting a 3-dimensional framework of the monkey’s physical traits from the 2-dimensional image containing laser dots for scale. This would allow us to infer measurements of body parts that are too foreshortened.
- Construct a graph/table that shows changes in offset of the vertical lasers at roughly half-meter vertical increments. Example: at 44 degrees the offset of the vertical lasers is +1.3cm.
Other thoughts from our time in Ecuador using our camera rig:
- Blurry if there was too much movement or if the lighting was not right
- Back-lit monkeys were difficult to get measurements on, fuzzy edges, haloed.
- Zoom Capabilities of 300mm lens at distances greater than 30m.
- Tripod not feasible for shooting in the field, maybe for re-calibrating? But that was okay because of fast ISO.
- Calibration, re-calibration
- Foreshortening of body parts distorted measurements
- Comparison of Lina laser measurements v actual measurements
- Did not have digital clinometer hooked up to camera, so had to waste time using regular one instead of getting a shot.
- Did not always use stable surface for target calibrations-- some of the time the target may not have been perfectly perpendicular to the path of the lasers.
- Possible to get shots (we weren't even sure we would be able to see monkeys in within range of the camera)
- If there were lasers on the monkey in one series of shots at the same angle and same distance, and the monkey doesn’t move, the values of that one shot can be transposed to other shots in that series.
- Pelican Case was amazing
- Zip ties/plastic construction worked fine
- Ability to shift camera to make lens converge with lasers
- Red vs Green Lasers. Red lasers worked very well in the canopy.
- Team of two people - holding case, spotting, extra set of eyes for finding monkeys, while the other person takes pictures.
- Battery and electronics stood up well to the conditions of the jungle.
- Camera/Lens - ISO and settings that worked best, ability to take several photos in quick succession without having to use Rapid Shoot-- Rapid Shoot was not as useful.
- Found that it was better to judge pixel-to-centimeter ratio using target without lasers on it-- center points of lasers became distorted at distances greater than ~28m, making it difficult to judge center point of the ellipses and correct orientation in relation to the center points of the target.
Impressions of Tiputini for further Research:
There are about a dozen active camera traps on the Tiputini reserve. They are older model digital cameras that use motion sensors to capture shy or rare creatures in the jungle. Diego, the camp’s director, showed us a number of the photos of rare and some never before seen creatures - amazing stuff. I personally think this is the best area for continued work between ITP and Tiputini. The image quality from the off-the-shelf camera traps wasn’t particularly great. They also weren’t optimized to the conditions in the jungle.
Tiputini is visited year-round by undergraduate groups from around the country/world. In addition to exploring the rain forest, the groups attend a number of educational activities and semi-research related tasks. It would be interesting if sponsoring, setting up, and then monitoring camera trap activities could be incorporated into their activities as way to fund and manage additional camera traps on site. It would be a great way to prolong the impact of their trip to the jungle and perhaps bring additional funding/press to the research station.
xBee Range Test---
Along with our monkey/laser gear, we also brought along 2 xBee modules to do range tests with. One of the modules was a base station with data logging capabilities. The other unit had a GPS chip and was designed to send coordinates back to the base station. Equipped with both whip antennas and a large 900 MHz antenna we tried to determine the effective range of xBees in the jungle.
GPS module - The GPS turned out to be an older model unit. We were unable to get a location lock while underneath the canopy.
Large 900 MHz antenna - we were never able to pick up a signal at a distance of more than ~50m while using the 900 MHz antenna. We thought that either the antenna was underpowered (we tried recharging/changing batteries) or that it was extremely directional and not appropriate for what we were trying to do.
Whip antenna - Using a secondary GPS unit for measurement, ~400-500m was the longest range at which we were able to connect the two devices. We tested the whip antennas with the base station located at both the bottom and top of the 30m canopy tower. We got the 400-500m range when both units were underneath the canopy. When the base was in the tower, above the canopy the max range was much less <200m. A monkey, unlike us, would likely be in the canopy, not below the canopy.