https://wiki.hoku.emelibrary.org/ 2026-05-25T09:11:34+00:00 https://wiki.hoku.emelibrary.org/ https://wiki.hoku.emelibrary.org/_media/wiki:logo.png text/html 2025-06-26T09:36:08+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.hoku.emelibrary.org/basic_level:algorithms_available_in_cupboard?rev=1750930568&do=diff Basic Level – Algorithms Available in Cupboard Read, Write, Display Change Size, Orientation Enhance Appearance Spectral Analysis text/html 2025-06-25T16:21:45+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.hoku.emelibrary.org/basic_level:browse_to_find_the_image_file?rev=1750868505&do=diff Browse to Find the Image File You probably do not want to type in the full path name of the image, so instead you can browse for the filename of the image. In the dialog box select the “Browse” button. That brings up a window to let you navigate through the file system to find the image file you wish to view. text/html 2025-06-25T16:18:50+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.hoku.emelibrary.org/basic_level:dynamic_variables?rev=1750868330&do=diff Dynamic Variables Dynamic variables are words of your choice, surrounded by $. In the example below, you see two dynamic variables, one for the “filename” in ReadImage and one for the “title” in Show. These variables were entered by selecting the corresponding check box with an empty text box. The name of the argument was used, but you can change those names to any name that you want, as long as it has no special characters. text/html 2025-06-25T16:11:57+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.hoku.emelibrary.org/basic_level:entering_arguments?rev=1750867917&do=diff Entering Arguments Left-clicking inside a module on the Desktop will bring up a dialog window where the arguments can be set. In this case, ReadImage has five possible arguments to be defined. The most important one, the one that is required, is “filename”, or the name of the image to be brought into the job. When there is a horizontal gray line, it separates the argument entries into two groups. Being above the line means that you must fill that entry. When all required entries have been… text/html 2025-06-26T09:33:11+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.hoku.emelibrary.org/basic_level:pca_principal_components_analysis?rev=1750930391&do=diff PCA – Principal Components Analysis Principal Components Analysis – PCA – looks for variance in the multispectral data and re-orients the axes of the data to order the data in the direction of decreasing variance. At times, this can reveal difficult-to-see text by separating the low contrast information from the high contrast information. text/html 2025-06-26T08:24:33+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.hoku.emelibrary.org/basic_level:readimage_and_show?rev=1750926273&do=diff Arguments for ReadImage and Show ReadImage Besides the required argument of the input file name, “ReadImage” also has three optional arguments and a flag. The spectral “bands” argument picks out specific bands from the image. The “window” argument reads only from a rectangular window on the image. The “multipage” number specifies an image from a multiple-image TIFF file (multiband Gimp file). The “calibration” flag says to look for a calibration file with the image. Creating a calibration f… text/html 2025-06-26T09:30:24+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.hoku.emelibrary.org/basic_level:readstack_multispectral_image?rev=1750930224&do=diff ReadStack – Multispectral Image ”ReadStack” reads several separate images and outputs one multispectral image. The number of spectral bands in the output image is the same as the total number of bands of all of the input files. The bands of the first image are put in the lowest numbered bands in the output. The bands from the last image are located in the highest numbered output bands. text/html 2025-06-26T08:45:52+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.hoku.emelibrary.org/basic_level:writeimage?rev=1750927552&do=diff WriteImage WriteImage can write in any of 6 image formats, Tiff, Envi, Jpeg, Png, Bmp, and Text files. The last format, Text, produces a simple text file, with a format that is unique to Hoku. The extensions of “.tif”, “.hdr”, “.jpg”, “.png”, “.bmp”, “.txt” are required in the names. Tiff is an archival format. ENVI is good for computations, and JPEG should be used only for display.