Understand the visual characteristics of main ground objects (rivers, mountains, fields, highways and urban areas, etc.). ), as well as their image geometry, image information reflection mode and basic ENVI/O operation.
Second, the experimental content
Under the guidance of my teacher, I used ENVI software to complete the input, display and output of TM 1 ~ 7 band remote sensing image data. Analyze the image characteristics of different ground objects in the same band, determine their image characteristics, and find out their differences in image characteristics; Identify recognized features with words.
Third, the experimental requirements
Preview this experiment, carefully observe the teacher's demonstration, strictly follow the experimental steps, and record the important experimental process, phenomena and technical parameters. Master the basic operation of ENVI I/O, and learn to visually identify the main types of ground objects (rivers, mountains, fields, highways, urban areas, etc.). ) in the image, and find the main characteristics differences between them, so as to understand the geometric composition of remote sensing digital images and the way of image information reflection. The measurement results are archived. Write an experimental report.
Fourth, the technical conditions
① Microcomputer; ② Guilin TM 1 ~ 7 band data; (3) ③ENVI software; ④Photoshop software (above version 6. 0) and ACDSee software (above version 4.0).
Verb (abbreviation of verb) experimental steps
(1) Create your own satellite remote sensing image data folder for practice. For easy search, it is best to use the internship group number or folder name.
(2) Data input. Copy the folder of "First Internship Materials" provided by the laboratory to your own internship folder.
(3) Open the image. After clicking the ENVI software icon, follow the following steps in turn:
1) Open the single-band image of TM 1 ~ 7 band image: "File >; OpenImage Files ",find the folder for storing TM 1 ~ 7 band image data, click TM 1 ~ 7 band data file (only 1, 2, …, 7 files without suffix are selected, and files with HDR suffix are not selected), press and hold the Ctrl key to complete the selection at one time, and then click the open button, and all seven band data will enter".
The "Available Band List" dialog box displays the information and parameters in the header file of remote sensing data, including band names: number of rows, number of samples and number of bands; File size; Cross format (BSQ, BIL, BIP); Data type (bytes, integers, etc. ); And whether the data has been located in geographical coordinates.
2) Under the "Available Band List" dialog box, use the cursor to select "Gray Level" (so that the small black dot appears in the small white circle), and then click with the mouse to select the band number to be opened (for TM7 band, select "Band 1" under the "7" subdirectory instead of "Map Information"). After selection, the size (size) of the band image appears in the "Dims" box below, such as 1024 × 1024, that is, the image has 1024 rows and 1024 columns, as shown in Figure 2- 1
3) Click the Load Band button to open the TM7 band image. At this time, three windows appear, namely: main window-complete image; Scrlol window-scrolling window, the main window is reduced by 0.25 times with the cursor as the center; Zoom window-The main window is magnified 4 times with the cursor as the center. Usually, only the main window is used to observe images.
(4) Comparison of corresponding areas (positions) between images of different bands. According to the method provided in step (3), enter more than two band images in the "Available Band List" dialog box, and open one of them first. Then click "Show # 1" at the bottom of the "Available Band List" dialog box, and two lines of drop-down menus will appear. Select "New Display", and a new image display empty window will appear immediately, and the second image will open in this window. At this time, two images with different bands are displayed on the screen at the same time. Enlarge and juxtapose the main windows of two images, and select Link from the Tools drop-down menu to open the Link Display dialog box. Click OK button to directly observe and compare the gray difference of the corresponding area (position) in the two images.
(5) Image output. Open the "FiIe" drop-down menu at the top of the main window, then open the "save image as" drop-down menu on the right, and select "image file …" to display in the "output display to image file" dialog box, as shown in Figure 2-2.
Figure 2- 1 Available Band List Window
Figure 2-2 Output Display to Image File Dialog Box
Select the output image format type through the Output File Type dialog box. If it is the final result, generally choose JPEG format, if you need ENVI processing, choose IMG type. The output file name is TM7.JPEG, which is stored in its own working folder.
(6) Repeat the operations from step (3) to step (4) for TM 1 ~ 7 band to obtain TM 1. TM6.JPEG。 Visually observe the remote sensing images of these seven different bands, and complete the following work:
I) Describe the display feature differences of seven remote sensing images in different bands, record them with W ORD document, and name them "Guilin TM 1 ~ 7 Band Image Feature Difference Analysis" and save them in your own working folder.
2) Open the JPEG image in TM 1 ~ 7 band with Photoshop software, and mark the identified ground objects, such as rivers, mountains, fields, highways, urban areas, etc., with appropriate red bold characters. The results are named as interpretation maps and stored in your work folder.
An experimental report on intransitive verbs
(1) Briefly describe the experimental process.
(2) Answer the question: ① What characteristics does the same feature reflect on TM images in different bands? (2) What characteristics do different ground objects reflect on the same band TM image? ③ What can we learn from the conclusions of questions ① and ②?
See Appendix 1 for the format of the experimental report.