![]() ![]() Whenever you are asked to comment on a pie-chart and describe the data you must remember that it must have a concrete structure. How to Structure Your Response to a Pie-Chart? This task assesses your ability to identify the most important and relevant information and trends in a graph, chart, table or diagram, and to give a well-organised overview of it using language accurately in an academic style. However, writing more than 150 words is acceptable. You will have to write at least 150 words and will be penalised if the answer is too short. Since time is a big factor, you must spend no more than 20 minutes on this task. Some minor points or details may be left out. For this you should adopt academic or semi-formal/neutral styles and include the most important and the most relevant points in the diagram. In Writing Task 1, you either will have to describe facts or figures presented in one or more graphs, charts or tables on a related topic or explain how a machine, a device or a process works, by looking at the given diagrams. Let us see how we can achieve this! IELTS Academic Writing Task 1 Format Since it is an analytical writing, the description must contain a range of contextual vocabulary. The perfect description must contain all the information explained in clear language. Multispectral imaging captures image data within specific wavelength ranges across the electromagnetic spectrum.Describing pie-charts is one of the most common questions in IELTS Academic Writing Task 1. The wavelengths may be separated by filters or detected with the use of instruments that are sensitive to particular wavelengths, including light from frequencies beyond the visible light range, i.e. It can allow extraction of additional information the human eye fails to capture with its visible receptors for red, green and blue. It was originally developed for military target identification and reconnaissance. Early space-based imaging platforms incorporated multispectral imaging technology to map details of the Earth related to coastal boundaries, vegetation, and landforms. Multispectral imaging has also found use in document and painting analysis. Multispectral imaging measures light in a small number (typically 3 to 15) of spectral bands. Hyperspectral imaging is a special case of spectral imaging where often hundreds of contiguous spectral bands are available. Multispectral imaging measures light emission and is often used in detecting or tracking military targets. In 2003, researchers at the United States Army Research Laboratory and the Federal Laboratory Collaborative Technology Alliance reported a dual band multispectral imaging focal plane array (FPA). This FPA allowed researchers to look at two infrared (IR) planes at the same time. ![]() Because mid-wave infrared (MWIR) and long wave infrared (LWIR) technologies measure radiation inherent to the object and require no external light source, they also are referred to as thermal imaging methods. The brightness of the image produced by a thermal imager depends on the objects emissivity and temperature. Every material has an infrared signature that aids in the identification of the object. These signatures are less pronounced in hyperspectral systems (which image in many more bands than multispectral systems) and when exposed to wind and, more dramatically, to rain. Sometimes the surface of the target may reflect infrared energy. This reflection may misconstrue the true reading of the objects’ inherent radiation. Imaging systems that use MWIR technology function better with solar reflections on the target's surface and produce more definitive images of hot objects, such as engines, compared to LWIR technology. However, LWIR operates better in hazy environments like smoke or fog because less scattering occurs in the longer wavelengths. Researchers claim that dual-band technologies combine these advantages to provide more information from an image, particularly in the realm of target tracking. Įor nighttime target detection, thermal imaging outperformed single-band multispectral imaging. Dual band MWIR and LWIR technology resulted in better visualization during the nighttime than MWIR alone. The US Army reports that its dual band LWIR/MWIR FPA demonstrated better visualizing of tactical vehicles than MWIR alone after tracking them through both day and night. ![]()
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