Welcome to this weeks remote sensing topic revolving around multi-spectral analysis through spectral enhancement. Essentially this means to take existing spectral data and present it in a manner that might bring out certain relationships or patterns not readily present in other presentations. This weeks objective was to study an image set and identify certain spectral relationships that aren't readily seen looking at a standard true color image. This is done by manipulating that pixel values to show other relationships through gray scale panchromatic views of single spectral bands or different combinations of multiple bands such as that seen from a standard false color infrared image. Both ERDAS Imagine and ArcGIS were used to explore the given image. Several tools within ERDAS were used, such as the Inquire cursor to look at particular groups of pixels for there relevant brightness information. Histograms and contrast information were used to identify patterns within multi-spectral and panchromatic views of one or more spectral bands. The image manipulated below was provided by UWF, and the assignment was to identify three different sets of unique spectral characteristics present within the image and to build maps around those.
The first criteria involved locating the feature in spectral band 4 that correlates to a histogram spike in value between 12 and 18.
As stated above, the first criteria involves investigation specifically into band 4 which is generally associated with near infrared (NIR) energy and is good for looking at vegetation and soil and crop land and water contrasting. With this task I needed to look at the histogram and find the resulting spike seen in the lower right inset of the histogram in question. From there I specifcally made this the only "visible" feature in the map to the left of it. You can see that in both the standalone feature map and the gray scale band 4 that the water does stand out quite significantly.
The second criteria involved locating the feature that represents both a spike in the visual and NIR bands with a value around 200, and a large spike in the infrared layers of bands 5 and 6 around pixel values 9 to 11.
The main features of this image are displayed in a false natural color employing bands 5,4,3 in that order for red, green, and blue. This color combo does particularly well at letting the areas that are being inquired about be displayed You can see that the insets display different extents of the same data in different spectral scenes. The two separate breakdowns of pixels of value 200 in Visual bands and values 9-11 in the infrared bands are compared in the lower right. In the visual inset in the lower left this appears to be snow within some mountainous valleys.
The last criteria being looked for revolves around water features that when looking at bands 1-3 become brighter than usual, but remain relatively constant in bands 5 and 6.
A true or natural color image is opposite a custom arrangement of bands 6 displaying band 7 short wave IR, and green and blue bands showing their own respective colors for enhancement. If you look at the natural color image you can see a river in the upper right portion that is much darker than the water way that is featured in the other images. This inlet is then highlighted spectrally in the other images. Focusing on the green and blue and removing the red, allowing for pinks and reds to be limited to open ground you get a much better highlight of the likely shallower inlet area. You can see also that false color IR does highlight the bay only by contrasting it against the vegetation which stands out so well.
Wrapping it up this assignment was about taking one image which is a combination of bands of spectral information and organizing that information in different ways to make certain features more readily apparent over others. Thank you.
The first criteria involved locating the feature in spectral band 4 that correlates to a histogram spike in value between 12 and 18.
As stated above, the first criteria involves investigation specifically into band 4 which is generally associated with near infrared (NIR) energy and is good for looking at vegetation and soil and crop land and water contrasting. With this task I needed to look at the histogram and find the resulting spike seen in the lower right inset of the histogram in question. From there I specifcally made this the only "visible" feature in the map to the left of it. You can see that in both the standalone feature map and the gray scale band 4 that the water does stand out quite significantly.
The second criteria involved locating the feature that represents both a spike in the visual and NIR bands with a value around 200, and a large spike in the infrared layers of bands 5 and 6 around pixel values 9 to 11.
The main features of this image are displayed in a false natural color employing bands 5,4,3 in that order for red, green, and blue. This color combo does particularly well at letting the areas that are being inquired about be displayed You can see that the insets display different extents of the same data in different spectral scenes. The two separate breakdowns of pixels of value 200 in Visual bands and values 9-11 in the infrared bands are compared in the lower right. In the visual inset in the lower left this appears to be snow within some mountainous valleys.
The last criteria being looked for revolves around water features that when looking at bands 1-3 become brighter than usual, but remain relatively constant in bands 5 and 6.
A true or natural color image is opposite a custom arrangement of bands 6 displaying band 7 short wave IR, and green and blue bands showing their own respective colors for enhancement. If you look at the natural color image you can see a river in the upper right portion that is much darker than the water way that is featured in the other images. This inlet is then highlighted spectrally in the other images. Focusing on the green and blue and removing the red, allowing for pinks and reds to be limited to open ground you get a much better highlight of the likely shallower inlet area. You can see also that false color IR does highlight the bay only by contrasting it against the vegetation which stands out so well.
Wrapping it up this assignment was about taking one image which is a combination of bands of spectral information and organizing that information in different ways to make certain features more readily apparent over others. Thank you.
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