Analyzing digital images for classroom environmental research

Mort Sternheim and Rob SnyderSTEM Education Institute

University of Massachusetts Amherst

NSF DRL-1031115NSF DRL-1031115

Today’s agendaIntroduction to Color Basics and Analyzing Digital

Images (Rob)Some examples of using a digital camera as a

scientific instrument (Mort)Today’s materials (and much more) are available at

the UMass Stem Education Institute web site at:

www.umassk12.net/digital/materials.html

The Big IdeaDigital cameras and computers are widely available

for students and teachers. However, they are mainly used for documentation: creating PPT presentations, handouts, posters, etc.

STEM DIGITAL shows how digital image analysis can be applied to environmental (and other) research in STEM courses

Application to studies of air quality, water quality, arsenic contamination

Other examples from climate change, diffusion …

Analyzing Digital Images SoftwareDeveloped by John Pickle, Concord Academy (formerly at the

Museum of Science, Boston)Free, student friendly, for Windows and Mac

Color and digital image basicsSpatial, intensity, spectral, temporal analysis toolsUpdated by Dan Gullage, STEM Ed

ADI (today’s version): www.umassk12.net/adi Newer version: http://www.globalsystemsscience.org/software/download

Summer InstitutesJune 25 - 29, 2012 at UMass Amherst Middle/High School STEM teachers; teams Participants MUST bring a digital camera, and are

encouraged to bring a laptop computerStipends ($375 summer), materials, parking,

lunches Housing for those outside the commuting radius 3 graduate credits available at reduced cost; free

PDP's (Professional Development Points) Summer 2013: Online grad course

Academic year componentOnline support via Moodle, emailKit with key materials for air quality, arsenic, water

quality collaborative projectsAdditional 3 credit reduced cost option or free PDP’sAdditional $300 stipend$200 budget for classroom materials

What ADI can measureGeometry

Area, length, anglesIntensityColor (RGB spectral analysis)Time evolution

Moving objectsGrowing or changing organisms, ecosystems

Use images from digital cameras, remote sensing web images

Mon., June 25 Tues., June 26 Wed., June 27 Thur., June 28 Fri., June 29

Geometry Color/ Air quality Time/ Ozone Arsenic Water/ Intensity

8:30 AM

Coffee and Registration Lobby of ISB

Coffee Coffee

Coffee .

Coffee

9:00 AM

Welcome, intros Areas – leaf, leaf color (J ohn), ice cap (Mort)

Color basics – light (Rob) ADI color matching (John)

Time lapse/ video (John)

Arsenic (Julian) Water quality

10:30 Break Break Break Break Break

10:45 AM

Complete ice cap Areas – aiptasia (Jennifer)

Making ozone strips (Hasbrouck 2xx) (Debbie, Steve)

Time lapse/ video Arsenic Water quality

12:00 PM

Lunch Lunch Lunch Lunch Lunch Evaluators Visit

1:00 PM

Angles – tree limbs (John) Angles – Size of the earth (Steve)

CO2 Experiments (Steve, Debbie)

Brainstorm – time

Arsenic Intensity – albedo (Mort)

Ozone

2:00 PM

Lengths – diffusion (Jennifer) Brainstorm -geometry

Careers – ppt, breakout

3:00 Break/ photos Break Break Break

3:15 Water quality (Dave)

Brainstorm - color CO2 ppt

Ozone Arsenic

4:00 PM

Brainstorm – more ideas

5:00 PM

Water lab tour BBQ at 7

Arsenic tour

We used inexpensive spotlights to mix Red, Green and Blue light and produced interesting results

A wide variety of devices that mix red, green and blue light are available.

Primary and complementary colors of light are commonly illustrated in this fashion.

Note: Any 3 colors from three different regions of the visible spectrum can be chosen as primary colors.

Human Eyes Have Photoreceptors Our eyes have two main types of photoreceptors,

rods and cones. These cells are in the retina, a layer at the back of the eye.

Cones allow us to see colors. They less sensitive than the rods and only work in bright light.

Rods let us see in dim light and show the world to us in black and white. This is why you see only black and white outside at night or in a dimly lit room.

L cones have a peak detection of greenish-yellow. M cones have a peak detection of green .

S cones detect principally blue and violet colors.

The letters L, M and S refer to Long, Medium, and Short Wavelengths

The ADI Software/Brain Analogy

Our brain detects a wide range of colors by analyzing the data it receives from cones on the retina.

The ADI software in a computer analyzes data it receives from sensors in a camera.

The Eye/Digital Camera Connection A digital camera is similar in many respects

to our eyes. Digital cameras have sensors that also detect the intensities of light in the red, green, and blue ranges of the electromagnetic spectrum.

Our eyes and digital cameras detect light in the red, green and blue portions of the spectrum that has been reflected from an objectBlue surfaces are mostly detected by the camera’s

blue sensorGreen surfaces are mostly detected by the camera’s

green sensorRed surfaces are mostly detected by the camera’s

red sensorBut yellow surfaces will be detected by the green

and the red sensors

ADI can produce a graph of colors along a line to reveal changes in a color.

The ADI rectangle tool can analyze an area.

Average Intensities: Red = 62%, Green = 49%, Blue = 34%

Yellow is a difficult color to create with inexpensive lights.

PixelsA pixel is a “picture element”, smallest block of color

in a digital picture or on a computer monitor. The more pixels, (usually) the better the image.

An intensity example: albedoIn polar regions, when snow or sea ice melts

exposing tundra or water, more sunlight is absorbed.This decrease in the fraction reflected or albedo

provides positive feedback, increasing warming trends

You can measure ratio of albedo to that of a standard, e.g., white Xerox paperAlbedo of white Xerox paper is about 0.5

ColorToday

Water qualityCarbon dioxide measurements

Website: Arsenic in water, rice, pressure treated wood…

Health of plants – effects of nutrients, pollutants …

Color example: Water qualityVolatile organic matter from decaying plants must be

removed from water suppliesTreatments use activated charcoal, alum, chlorine,

“home or recreational treatment” ( 1 to 4)

Assessing the treatments

Some research questionsHow much alum, etc., do you need?Want kind of leaf material would leach the most

organic matter? Old dry leaves or young green ones? Coniferous or

deciduous? Oak or maple? Tree or grass? Large leaves or small ones?

Does light matter? Does the time in the water matter?Does frequent mixing matter? Does oxygen matter?Is there is a difference between distilled and highly

mineralized water?

More water quality research questionsWhat is the effect of

pHSalinityTemperatureParticle sizeAmount of sunlight

on the process of leaching?

Another color example: CO2pH BTB indicator (bromothymol blue) changes color from

blue to yellow as the acidity increasesGood for measuring ~ neutral pH (7.6 to 6.0). Used to

observe photosynthetic and respiratory activity.CO2 bubbled in BTB solution makes carbonic acid,

changes colorUse diluted solution (6 ml 0.04% plus 90 ml water)Blow up balloon, use syringe to measure 50 ml, inject

into waterCompare control, room air, breath; breath after exercise

Carbon dioxide experiment

Carbon dioxide research ideasTest pure CO2.made with baking soda, vinegarTest car exhaustsInvestigate variations in atmospheric CO2 levels:

urban, rural, roadways; well ventilated spaces, stuffy classrooms, etc.

Investigate reduction of CO2 levels due to photosynthesis

Investigate increase in CO2 levels due to combustionInvestigate response of various plants to increased

CO2 levels

GeometryAreas

Leaf, leaf coverPolar iceHands, feet, bodies of water …

LengthTree growthSolar areole – correlation with aerosolsDiffusion

AnglesSize of the earth – Eratosthenes: Tree or plant branches

Area measurement: Polar iceArctic cycle – max in March, min in Sept.Shrinkage over the past 30 yearsCompare / contrast Arctic, Antarctic annual sea ice cycles,

changes over past 30 years

Sept.1979

Sept. 2009

5/5/11 5/8/11

5/14/11 5/26/11

Trees – areas, lengths, angles

Length example: solar aureoleSolar aureole is a bright glow around the sunCaused by aerosols – suspensions of fine particles

or liquid drops in the airAerosols are usually dust, smoke, smogAureole is larger when the concentration is higherRain will tend to wash out aerosolsADI can quantify aureoles and provide air quality

data

Thursday, September 16, before rain

Friday, Sept. 17, 2010 (after rain)

Eratosthenes Calculated Earth’s

Circumference over 2000 years ago

Distance/Circumference = Angle / 360 An ADI angle tool can measure an angle formed by a post and it’s

midday shadow. That Angle and distance to a location with no midday shadow can be used to calculate Earth’s circumference.