{{ :light:banner-light-st3-790x50.jpg |Light ST3 Banner}} ====== LIGHT - INFRARED (IR) & NEAR-INFRARED (NIR) ====== === Obtaining an Infrared Webcam: === Most off-the-shelf webcams are infrared capable but purposely designed to ignore infrared light. To enable infrared capability usually only requires removal of a small glass/plastic filter from the webcam lens. No other modification is required to perform any of the experiments listed below. Some sites recommend replacing the infrared filter with another filter to block visible light but this is not necessary for any of the experiments listed here. In contrast to normal webcams, security or 'night vision' webcams are purposely designed to support infrared imaging 'out of the box' and require no modification. Any cheap security or 'night vision' webcam should work well as infrared video/photography. Many cameras include infrared flash or lighting but this is not required for the experiments designed below. Search ebay or your local electronics supplier for 'security webcam' - for example: **[[http://www.ebay.com.au/itm/SALE-WiFi-Wireless-HD-720P-CCTV-IP-Camera-Security-Night-Vision-Webcam-Monitor-/360777163736?var=&hash=item53fffea3d8:m:mY_2L5YEcZIl-tXQExSGLXg|Infrared webcam under $50]]** Neither camera will provide professional level, colourful theram images but for purpose of displaying simple infrared images during daytime (when most kids will be using the cameras), a modified $10 USB webcam will work just as well as a $50 - $100 security camera. The webcam used in our tests was a simple [[http://www.ebay.com.au/itm/Logitech-C120-USB-Web-Camera-Webcam-High-Res-1-3MP-Video-Audio-FREE-SHIP-/262215526677?hash=item3d0d436915:g:CMEAAOSw0HVWCM0P|$10 webcam]] that was modified as per this link: ** University of Cambridge: [[http://www.thenakedscientists.com/HTML/experiments/exp/make-an-infra-red-camera/|Build your own cheap NIR Webcam]]** **Find someone with 'maker' expertise to modify standard webcam or alternatively, any cheap off-the-shelf security webcam should work 'out of the box'** ---- === Curriculum Relevance & Outcomes: === USING INFRARED TECHNOLOGY, STUDENTS MAY EXPLORE a variety of products in the local environment, eg food products and industrial products. Students describe a range of manufactured products in the local environment and how their different purposes influence their design - ST1 BOS: http://syllabus.bos.nsw.edu.au/science/science-k10/content/962/ Students may also use infrared technology to identify the physical properties of natural and processed materials, and how these properties influence their use - ST2 BOS: http://syllabus.bos.nsw.edu.au/science/science-k10/content/968/ {{ youtube>xZVPhWxC9V8?640x360 |Infrared Radiation - How it works}} === Video 1. Infrared Radiation - How it works === * IF UNABLE TO ACCESS YOUTUBE VIDEO (requires Flash) TRY:[[http://viewpure.com/xZVPhWxC9V8|Infrared Radiation - How it works]] ---- === Introduction To The Physics of Infrared & Radiation === {{ youtube>hPJPbbT1TsM?640x360 |Infrared & The Radiation Spectrum}} === Video 2. Infrared & Radiation) === * IF UNABLE TO ACCESS YOUTUBE VIDEO (requires Flash) TRY:[[http://viewpure.com/hPJPbbT1TsM| Introduction To The Physics of Infrared & Radiation]] ---- ==== Investigating heat using infrared technology: ==== {{ :light:ball-thermal-bounce-640x200.jpg?640x200 |Ball Thermal Bounce Image}} Infrared radiation is emitted by all objects with a temperature above absolute zero according to the black body radiation law, making it possible to see one's environment with or without visible illumination. The amount of radiation emitted by an object increases with temperature: When viewed through a thermal imaging camera, warm objects stand out well against cooler backgrounds. As a result, infrared and similar heat-related photography (thermography) is widely used in cameras used for security, industrial trouble-shooting and health diagnostics. For example, government, airport and medical staff used thermography to detect suspected swine flu cases and prevent spread of the disease during the 2009 Swine Flu pandemic. Source: https://en.wikipedia.org/wiki/Thermography {{ youtube>xwov8AQEsyc?640x360 |Infrared Radiation}} === Video 1. Infrared Radiation) === * IF UNABLE TO ACCESS YOUTUBE VIDEO (requires Flash) TRY:[[http://viewpure.com/xwov8AQEsyc|Infrared Radiation]] ==== Infrared Webcam Hacking & Hints: ==== Cheap infrared webcams are robust, simple and surprisingly powerful tools that can be used to support classroom investigation, experimentation and invention for primary school students. === Setup === Defaults: * Set contrast HIGH and brightness LOW * Compare image with visible/IR light filter. Investigation of different materials can reveal that dyes are transparent to Near Infrared (NIR) but pigments are not transparent. Dyes get their coluor from being in solution while pigments have their colour just as being a solid. Chlorophyll in plants gets its color from being in solution. It is a dye and this is why green plants look white when viewed in NIR. Compare gift wrapping papers under visible and infrared light: * The patterns are often bright under visible light but disappear under IR * Hide RED, BLACK, BLUE print behind wrapping paper and reveal using IR Compare the natural world using an Infrared (IR) camera/webcam to look around outside: * Vegetation appears much brighter than normal. * Why? Could it be, for example, that plants can't use IR light for photosynthesis and that reflecting the unwanted light helps the plant avoid overheating. Compare liquids: * Pepsi/Coca Cola is relatively transparent at (NIR) wavelengths so if you point an Infrared camera/webcam at a glass of cola, you can see right through it! * Very cold/iced water may appear very dark compare with water at room temperature Compare images using different inks: * Images on many banknotes are printed with two different inks which look identical in visible light, but one of which is transparent to IR. This makes it harder to forge these type of banknotes. Forged paintings and documents are often discovered using infrared flourescence generated using tungsten or electronic flash techniques. Using an LCD digital microscope (or USB NIR camera), put flower petals on the specimen stage and illuminate them with a TV remote control, students will see wonderful markings and designs that only Bee's and Hoverflies ever normally see! * Fighting Fires [[http://www.popsci.com.au/robots/drones/manchester-firemen-use-drones-with-infrared-cameras-to-fight-fires-,410501|using infrared (IR) cameras & drones]] * Take a look at the images below - What problem(s) could you solve using a NIR webcam? Some plastic bags are transparent to NIR: * The polyethylene material in the bag scatters light primarily via Rayleigh scattering which is strongly wavelength-dependent. * Many black garbage bags are transparent - water is opaque! The physical reason why this is happening is that absorption of a medium is frequency dependent. Source: http://physics.stackexchange.com/questions/3750/why-is-a-plastic-bag-transparent-in-infrared-light === Normal 'visible' light image (left) compared with infrared 'see-through vision' (on right): === The following images can be obtained using cheap DIY modified (less than $20) webcams, or more expensive ($100 - $200) commercial grade cameras that can be used 'out of the box' (see below). === Using Near Infrared (NIR) to 'see through' envelopes & playing cards: === {{ :light:infrared:see_through_envelope_playing_card.jpg |Envelope}} === Use NIR to see through fabrics: === {{ :light:infrared:see_through_fabric.jpg |Fabric}} === Use NIR to see through fog: === {{ :light:infrared:see_through_fog.jpg |Fog}} === Use NIR to see through hay/vegetation: === {{ :light:infrared:see_through_hay.jpg |Hay}} === Use NIR to see through ink: === {{ :light:infrared:see_through_ink.jpg |Ink}} === Use NIR to see through lipstick and sunglasses: === {{ :light:infrared:see_through_sunglasses.jpg | Sunglasses & Lipstick}} === Use NIR to see through tinted windows: === {{ :light:infrared:see_through_tinted_windows.jpg | Tinted Window}} **Also see: http://www.kaya-optics.com/technology/how_ir_xray_vision_works.asp** ---- [[https://www.youtube.com/watch?v=FjHJ7FmV0M4|Richard Feynman talks about light]] ====== InfraGram and PublicLab ====== PublicLab Vineyards, large farms, and NASA all use near-infrared photography for assessing plant health, usually by mounting expensive sensors on airplanes and satellites. At Public Lab, we've developed a Do-It-Yourself way to take these kinds of photos, enabling us to monitor our environment through quantifiable data. * https://publiclab.org/wiki/near-infrared-camera Infragram is an online tool for analyzing plant health with near-infrared (NIR) imagery. * Infragram website: http://infragram.org/ * Plant analysis: https://www.adafruit.com/products/1722 https://publiclab.org/wiki/ndvi ====== Appendix ====== No - InfraRed is NOT a kind of heat. In his book " Clouds in a Glass of Beer," Physicist C. Bohren points out that this "heat" misconception may have been started long ago, when early physicists believed in the existence of three separate types of radiation: heat radiation, light, and actinic radiation. Eventually they discovered that all three were actually the same stuff: light. "Heat radiation" and "actinic radiation" are simply invisible light of various frequencies. Today we say "UV light" rather than "actinic radiation." Yet the obsolete term "heat radiation" still lingers. Since human beings can only see certain frequencies of light, it's easy to see how this sort of confusion got started. Invisible light seems bizarre and mysterious when compared to visible light. But "invisibility" is caused by the human eye, and is not a property carried by the light. If humans could see all the light in the infrared spectrum, we would say things like this: "of course the electric heater makes things hot at a distance, it is intensely bright, and bright light can heat up any surface which absorbs it." * http://amasci.com/miscon/miscon4.html#heat === Cheap IR Webcam === [[http://www.ebay.com.au/itm/USB-12MP-HD-CMOS-Camera-Mic-10xDigital-Zoom-Webcam-Infrared-Night-Vision-for-PC-/351462396676?hash=item51d4ca9304:g:HXQAAOSw~gRVsNxE|Aveo Webcam]] {{ :teaching:stem:infrared:aveo-ir-webcam-01.jpg|Aveo IR Webcam}} Bus 001 Device 003: ID 1871:0142 Aveo Technology Corp. Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 2.00 bDeviceClass 239 Miscellaneous Device bDeviceSubClass 2 ? bDeviceProtocol 1 Interface Association bMaxPacketSize0 64 idVendor 0x1871 Aveo Technology Corp. idProduct 0x0142 bcdDevice 0.0c iManufacturer 1 AVEO Technology Corp. iProduct 2 USB2.0 Camera iSerial 0 bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 546 bNumInterfaces 4 bConfigurationValue 1 iConfiguration 0 bmAttributes 0x80 (Bus Powered) MaxPower 500mA === Linux, Raspberry PI Webcam Software === For advanced users, take a look at: * **Motion** Linux Webcam [[http://www.lavrsen.dk/foswiki/bin/view/Motion/|software for projects]] * **Howto** install and operate [[http://www.linux.com/learn/tutorials/780055-how-to-operate-linux-spycams-with-motion|linux 'motion' software for projects]]