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Resolution Gis

The document discusses various types of satellite sensors used in remote sensing, including cameras, solid-state scanners, and multispectral imaging systems. It emphasizes the importance of spatial, radiometric, and temporal resolution in determining the quality and detail of the images captured by these sensors. Additionally, it outlines the operational principles of optical-mechanical and optical-electronic scanners, highlighting their roles in capturing and processing data from different parts of the electromagnetic spectrum.

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Neha Negi
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19 views15 pages

Resolution Gis

The document discusses various types of satellite sensors used in remote sensing, including cameras, solid-state scanners, and multispectral imaging systems. It emphasizes the importance of spatial, radiometric, and temporal resolution in determining the quality and detail of the images captured by these sensors. Additionally, it outlines the operational principles of optical-mechanical and optical-electronic scanners, highlighting their roles in capturing and processing data from different parts of the electromagnetic spectrum.

Uploaded by

Neha Negi
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Satelite and Sensors 135 day or night, even under cloud cover, and (ii) image plane scanning, e.g. passive phased array radar. Spaceborne sensors which are more familiar and widely used in remote sensing: are the camera, solid state scanner, such as the CCD (charge coupled device), the multi-spectral scanner and the radars. 5.3.1 Spatial Resolution and IFOV ‘The detail of information extracted from an image as well as the total area on the ground imaged by the sensor largely upon the resolving power of the sensor and the distance between the target and the senso. The concept resolviny power of the sensor_or resolution is a complex attribute that describes how much detail in an eee is visible to the human eye for identification. This may it of as the eye or sensor to see fine detail. to resolve objects on the image. discrimination or separation between abies =p ingen JEzsolution_can be aaa as the abilit Srine iaecian deena ee i eae ace a + George ving power or minimum resolvable distance of an es sable once oe ‘ice is the angular separation on between two objects in an .er resolution means more image detail. Saiacal resolution is defined as the size of the smallest object that can jiscriminated by the sensor gSpatial resolution is a meas i “the i ance between two objects that will allow them to image (Sabins, 1978; Jensen, 1996). This is a : é 7 al sare) detector size, focal size and system configuration. For aerial ‘aerial photography the spatial tial resolution is resolvable line pairs ; Satelite and Sensors 135 day or night, even under cloud cover, and (ii) image plane scanning, e.g. passive phased array radar. Spaceborne sensors which are more familiar and widely used in remote sensing: are the camera, solid state scanner, such as the CCD (charge coupled device), the multi-spectral scanner and the radars. 5.3.1 Spatial Resolution and IFOV ‘The detail of information extracted from an image as well as the total area on the ground imaged by the sensor largely upon the resolving power of the sensor and the distance between the target and the senso. The concept resolviny power of the sensor_or resolution is a complex attribute that describes how much detail in an eee is visible to the human eye for identification. This may it of as the eye or sensor to see fine detail. to resolve objects on the image. discrimination or separation between abies =p ingen JEzsolution_can be aaa as the abilit Srine iaecian deena ee i eae ace a + George ving power or minimum resolvable distance of an es sable once oe ‘ice is the angular separation on between two objects in an .er resolution means more image detail. Saiacal resolution is defined as the size of the smallest object that can jiscriminated by the sensor gSpatial resolution is a meas i “the i ance between two objects that will allow them to image (Sabins, 1978; Jensen, 1996). This is a : é 7 al sare) detector size, focal size and system configuration. For aerial ‘aerial photography the spatial tial resolution is resolvable line pairs ; ss a eal revtook of Ramote Sensing and Geographical informa | & }! 136 resolution, and data volume. the data volume aerial extents lution, the greater Tf data volume constant, De esolution,imag ee image {Sabins Sverage wit 1" nage Sabla i ic as Spatial resolution ‘ imageba z Spaced objects on an imag ae Snot the size of the smallest ol ution are ie at other terms s\ seen”. He also points 0 aa izability, signature, and texture have a recognizability, ce -qualitarive—amalysis ‘of images. “In fa Fesolution are t and these factors deter of imagery. Spatial resolution of the image is ve when choosing the best source for a given apf resolution imagery will generally be more expen resolution imagery, but it will also allow you to se« detail in the landscape, High-resolution images are ‘many small deralls tan be seen, but even the b a limit to their resolution. The spatial_resolut acquired by satellite sensor systems is — y meters, For example, we often speak of Systemis on IRS 1C PAN as having “six n means that two objects, six meters long or wi side, can be separated (resolved) on an I resolution is directly related to image pix sensing each pixel represents in the real wor ground resolution element-an atte a ground resi faeene: ©, the IRS-IC has résolution =a te m. In this case as smaller the resc ‘er one can resolve image spatial c Instantaneous Field of View (IFO} The field-of-view (FOV) is th the incident radiation can be coll of view may be’ resolved ; com) ts, label int Peciah ie samt OM I i — ——— ve f E er Textbook of emote Sensing and Geograph omg ai olution of multispectral a es ‘romatic image.) sing btain b several marrow a oe phile One wer classification “ed visible red energy, another set ease energy. These multiple eeflectans iniraredencigy “ca. The present day multisp to create color imag flectance values in sing satellites Gifferent bands at oncey The sensorJis 4 carer ream cical bande, Each channels se wrihin a narrow wavelength band) The resulting Glulayer image which contains both the bri ‘olour) information of the targets being observe systems use from three to six spectral ands in jniddle infrared wavelength region. Some systems als il na a aa in the in limited in width due to presence of many atmosp bands that significantly degrade the signal. multispectral systems allow discrimination of regetation, rocks and soils man-made materials.JA three band sensor near infrared bands is effective at discriminat non-vegetated areas) The IKONOS satellit a ™ rou) en TISS I sensor (36. lue band to,provide complete covera; fangeJand allow natural colomband com created. The Landsat TM (4 and 5) a sensors add two bands in the middle IR. | (1.55 ~ 1.75 jm) and band 7 (2,08 35 variati n_the moisture content Band 7 also covers a range that : idi fea found_in importan additional TM hia wavelength ae e oe mboaf BBB a ebook of Ramat Sensing and Geographical 142 windows in the atmosPhe! re may prove to be useful monitoring heric ¢ changes as well as cures: - 5.3.3 Radiometric Resolution . | ‘The actual information content in an image is det by the radiometric characteristics of a sensor. It is cor expressed as the number of bits (binary digits) needs t xP mum level, The radiometric resolution of system describes its ability to discriminate very i jn energy. The finer the radiometric resolution more sensitive it is to detecting small differences in r emitted energy. In a digital sensor radiometric re determined by the number of discrete levels into may be divided Te eau ae ividis to W) of the signal output of the sensor into a just discriminable levels so as to be able to features differing only~slightly Considering the effects of varying illumination dynamic range of a sensor is determined by 1 radiance value that the sensor can experience Satellite data are represented either in analog format. Digital number or DN value is the feature in the smallest slice of a band electromagnetic spectrum. Digital image can b range of digital numbers or DN values fr to black to a selected eat This red power of 2 corr range corresponds to the number numbers in binary format. Each 1g Ta (eg. 1 bit =2'= 2). The n gray levels available depends on the representing the energy re 10 bit radiometric ee i digital output signal into . %) quantisation levels), How ie the number of shades of g data are generally retook of emote Sensing and Geographical gray levels are not. visibility for identi extended by using digital ion from the available rad he radiometric resolution of data ag tem are compared with data acquired radiometric resolution instrument (€-8-» Vande Jaea) then the lower resolution data (¢ ; decompressed to 8 bits for change detection purposes. ¢ decompressed brightness values can the precision o} alues better than the original, uncompressed data in an The atmospheric contribution due to ab scattering decrease the radiometric resolution of reducing the discrimination between different rad especially at shorter wavelengths. Srila 5.3.4 Temporal Resolution In addition to spatial, spectral, and radic the concept of temporal resolution is also im in a remote sensing system. Temporal resoluti how often an area can be imaged. It is simply of temporal coverage of a sensor/platform | acquisition over an area and is only relevant ieraped ot rovide far from 30 shades Giscernible. an by one sys iain.

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