Questions tagged [digital-image-processing]

The field of raster image processing

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1answer
71 views

Detection of avalanche debris based on their distinctive shape

I want to detect avalanche debris of a known avalanche using Sentinel-2 optical imagery. I've calculated the Normalized Difference Snow Index and from there I've extracted all the values above 0.4 ...
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1answer
196 views

Why is ArcPy script looping through bands slow?

I am working on a single tiff with over 20k bands, each representing daily temperature, and I'll be extracting and preforming simple raster math on roughly 3500 of the bands. The problem I'm running ...
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1answer
812 views

Combining hyperspectral bands to form a multispectral image?

I understand that the difference between the two are the number and width of the bands. Given a hyperspectral image, is it possible to 'convert' it to multispectral ? In this paper for example, the ...
2
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2answers
191 views

Dot density map “slicing” dots when exported

I'm running ArcMap 10.3 and every time I export a dot density map it "slices" long, horizontal gashes in sections of the dots (see screenshot below). The cuts are never vertical, always horizontal, ...
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1answer
108 views

R Script for Computing Image Means and Raster Value Subtractions

I have a very specific script I am trying to make which computes image flatfields. Basically, I am computing a Master Dark Frame (MD) by averaging a set of Dark Photos. I have a set of light photos ...
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2answers
4k views

Supervised image classification in QGIS

Is it possible to do supervised image classification in QGIS? I require it for the estimation of cover management factor (C factor) in USLE
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2answers
776 views

How to manually reclassify a contiguous region of misclassified pixels?

The attached image is the result of an image segmentation algorithm on high resolution imagery. The smaller clusters of pixels represent trees and brush and the larger cluster of pixels (marked with ...
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0answers
26 views

Ingest 8-band satellite imagery into an array in C?

I’ve been unable to locate a lightweight library implemented in C to ingest 8-band geotiff files. GDAL can do this easily in python, though I’ve been unable to get the GDAL C libraries working; I’ve ...
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0answers
498 views

Remove near black borders on Landsat 8 overview images

I want to eliminate near black pixels around edges of Landsat-8 overview. I'm interested in doing it not for the entire image but some extent, so I clipped it. I tried using GDAL nearblack utility, ...
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0answers
62 views

How to create Strips with GCP point distribution for raw GeoEye satellite imagery?

I have raw GeoEye satellite imagery, I just want some guidelines for creating a strip map with GCP distribution. We need to make orthorectification for raw GeoEye satellite imagery, I think it's ...
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2answers
315 views

Validation points for supervise classification

I have undertaken supervised classification (maximum likelihood) and planning to survey the ground to validate the output. How many validation points do I need to take? The raster is a landsat tile ...
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0answers
8k views

Zero-size array to reduction operation maximum which has no identity

Below is my identify background code, which identifies a background from an image and removes it.; Previously it's was working fine but after I chunked my images and try to find out background I got ...
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2answers
2k views

Unsupervised raster classification using GDAL

Is there an equivalent in GDAL to the Arcpy ISO data unsupervised classification tool, or a series of methods using GDAL/python that can accomplish this?
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2answers
536 views

Looking for real-world DJI Phantom 3 Professional sample geo-tagged images for testing

I am looking for sample DJI Phantom 3 Professional imagery for testing purposes with the Drone2Map for ArcGIS Beta software. So far I am finding the application very polished and easy to use but I am ...
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1answer
415 views

How to Find Local Lowest Point(s) on a Landform?

I am trying to write a code to find the local lowest points using Python. This approach will be applied to raster landform data such as digital elevation models. What approach can I take to find the ...
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0answers
700 views

Why does ArcGIS Resample tool change cell size and numbers of columns and rows? [closed]

I am working with images of oxygen distribution within individual plant root systems submerged in water. The program I use to acquire these images, LookatRGB, splits the green band in half and makes ...
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0answers
63 views

Corrupted Image Layer of DPR File (eCognition Project)

I just started working with eCognition a few months ago and it is my first time to encounter a problem. I was on the refinement stage (and almost done manual brushing objects) when I found out that ...
3
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2answers
3k views

How to perform an accuracy assessment in eCognition?

How to do accuracy assessment of classified images in ecognition? I have done the image segmentation for Worldview-2 image. Then, I have processed for classification for class names (e.g road,...
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1answer
63 views

Globbing in Windows to process images - how do bash loops look in DOS?

I'm doing some batch image processing with imagemagick on OSX using this line: for file in $(cat all.txt); do convert -crop 50X50@ +repage +adjoin "$file" "$file"_tile_50x50@_%d.jpeg; done It takes ...
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0answers
383 views

ENVISAT ASAR .N1 file is not being opened by ERDAS IMAGINE 2011

I am not able to open ENVISAT ASAR .N1 file in ERDAS IMAGINE 2011. The software has direct read option for files of this format. Whenever I try to open the file, software closes automatically giving ...
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2answers
161 views

Installing pre-requisites for forest classification using SCP and QGIS?

I am using QGIS 2.8.6 and I want to use SCP for forest classification from Landsat 8 oli. I have already installed the SPP plugin. What else do I need to install for operation of the software?
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1answer
121 views

Plotting Vector data on Raster Map

I have a Raster map with East,West, North and south boundaries as follows (-118.875,-118.75,37.125, 37) and a Vector data. Now I want to plot a vector lines on this raster map. the vector line is in ...
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2answers
2k views

Auto digitizing features on map? [duplicate]

I'm new to digitization. I have the following map and I'm trying to digitize the purple features. Is there any way to automatically digitize all the purple lines on the map.
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1answer
582 views

Loop over GeoTIFF image pixels, extract coordinates and pixel color

I have a very large GeoTIFF image (~650MB) with color-coded landcover data from here. I need to extract the latitude, longitude, and pixel color for each pixel in the image, so I can import it into a ...
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0answers
55 views

Finding pre-processed MODIS products?

I am trying to recognize burnt areas based on some MODIS products and I just realized that I am missing a bunch pixels from the coastline masking. As you can understand that is an issue because I am ...
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1answer
675 views

Calculate NDVI with converted canon sx260 hs

I have converted my canon sx260 hs so it can capture NIR part of specter. Can anyone tell me how can i calculate NDVI now? My guess is that on the blue channel is now NIR value and Green channel=(...
1
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1answer
343 views

How to extract MODIS QA informaton

I want to use the LDOPE tool unpack_sds_bits to extract the bit information from the State QA layer of the MYD09GA Aqua Surface Reflectance product. However, I have never run a command line before ...
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0answers
62 views

Find densest point in satellite agriculture map [closed]

I have a .tiff image file with 3 bands. I want to write a program, (python opencv?), that will find the first N densest points in the region. Densest, meaning the point with the most of its own ...
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2answers
323 views

Pattern search in satellite imagery

I would like to search for the specific buildings (polyhouse in my case) on the map like the one shown here Are there any free options available which can give me lat and lng of such shapes/features ...
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1answer
118 views

Conversion of multispectral image to grey scale

I have a composite with four bands NIR, Red, Green and Blue. I would like help on which weight values to use when converting it to a single band which will then be used to classify vegetation. I am ...
11
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1answer
2k views

Multispectral image segmentation for natural-resources applications using R

R has the capacity for image segmentation, although all of the examples I have come across utilize a single band for the segmentation (example). I am interested in combining R's capacity for random ...
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0answers
640 views

How to convert .HDF to .Tiff and keep the number of the output files exactly as the input?

I have 332 .HDF files that I have processed in R to convert them to .Tiff. It has worked fine, however, the number of output files are not the same as the number of the input files! Input is 332, ...
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3answers
2k views

What preprocessing is required when using Landsat for LULC?

Can anyone help me regarding the what kind of image pre-processing techniques should be used for the landsat images downloaded from http://earthexplorer.usgs.gov/ to create land-use land-cover (LULC) ...
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1answer
1k views

Enhanced vegetation index using ENVI 4.7 bandmath

I computed Enhanced Vegetation Index using band math in ENVI 4.7 software. The expression used was: 2.5*((float(b1)- float(b2))/(float(b1)+ (6*float(b2)) +(7.5* float(b3)))) BYTSCL(float(b1), min = -...
3
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2answers
161 views

Pansharpening influence on analysis

Using as an example Landsat 8 bands: Does pansharpening band enhace only visible range and therefore can I use it only for analysis connected with visible spectrum? Or I can pansharpen every possible ...
6
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2answers
2k views

How to create a mosaic in QGIS with cutline and feathering for Landsat-8 imagery

1 - I have two scenes Landsat-8 RGB 6/5/4 and I need to mosaic them: 2- This is my cutline in polygon format that will smooth the overlapping area: 3 - So, I need to create a mosaic with feathering ...
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1answer
686 views

Make Image Pyramid from JP2 Raster

I have ~1.7 GB JP2 Buckeye that I want to serve out from Geoserver; I'd like to have it tiled so that the client won't have to redraw everytime they zoom into the map. My current understanding is that ...
1
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1answer
574 views

How to define a threshold in Principal Component Image for Urban mapping?

I am working on an Urban mapping and i would like to know how i could define a threshold value for extracting built-up areas from a PC (Principal Component) Image ? I am interesting on how to ...
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0answers
67 views

i.spectral tool error

system description: Windows7 32 bıt OS, Grass GIS 7.0.0 Gnuplot 5.0 Solution attempt 01: On the basis of following thread, commented out said path check lines from i.spectral.py script: https://...
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3answers
756 views

Extract DEM and DTM information from LIDAR image using E-Cognition

I´m trying to extract DEM and DTM from a LIDAR file. Currently, I rasterize the image but don´t know which algorithm I need to apply to obtain the DEM and DTM information in different models to be ...
6
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1answer
2k views

Random Forest land cover classification in ArcMap?

I am an undergraduate student working with a very large data set (to me), and who has NO experience with R, but is fairly comfortable with ArcMap. I have about 60GB of 8band 1m satellite imagery of ...
4
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1answer
99 views

Classifying areas in scanned maps (not by colors but by pattern)

I have old land-use maps in a scanned format. I am trying to obtain proper land-use maps from it, similar to what is decribed here: Comparing areas in scanned historical land use maps using QGIS?. The ...
2
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1answer
1k views

Segmentation - problem with mosaic tiles

Could you please tell me how to solve my problem with segmentation in ERDAS ? I am using ERDAS 2013 and the tool Image Segmentation to segment my multiband picture (with high resolution). ...
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2answers
647 views

Devide heatmap into meaningful clusters

I created a heatmap containing population density data. Now I want to figure out the hotspots of this heat map. In other words: Where are the biggest population densities in my map? My first thought: ...
6
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1answer
5k views

SAR - Using the Intensity or the Amplitude for the classification

In a Sentinel-1 Level 1 Ground Range Detected SAR data product, Intensity = Amplitude * Amplitude. Should the intensity image or the amplitude image be used for radiometric calibration when using ...
2
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0answers
49 views

How to digitize infrared slides for use in GIS?

I have an aerial infrared slide with the following dimensions 20cm x 30cm. It was captured with an infrared camera from a height of around 3000m a few years back and now my environmental agency would ...
4
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1answer
918 views

Otsu thresholding and classic image processing algorithms on radiometrically calibrated Sentinel-1 SAR images

Is it possible to apply the Otsu thresholding (or any other image processing algorithm dedicated to image digital values in the interval [0, 255]) to a Radiometrically calibrated Sentinel-1 SAR ...
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0answers
73 views

How to extact very narrow water linear features from GeoEye-1 image

I need to extract beaver channels from a GeoEye image (attached image). What is the best approach to automatically delineate such very narrow and not very sharp water features?
2
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1answer
386 views

How to suppress noises of this edge-detected image? [closed]

I've recently developed a new approach to detecting image edges. Everything seems to be normal except the noises! As you can see in the following image, there are many noises I'm not able to handle ...
18
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1answer
31k views

Panchromatic Image association with high spatial resolution

How and Why is a Panchromatic Satellite Image associated with high spatial resolution? I googled and found that it is a single band image, but then why is it called pan-chromatic(All Colors). Does it ...