Questions tagged [digital-image-processing]

The field of raster image processing

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Applying Linear Stretch Landsat 8 SR Using Google Earth Engine

I'm doing research indices of impervious surface, but for calculate the indices, the Surface Reflectance value of Landsat 8 should be converted to a value in the range 0 - 65535 in order to maintain ...
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GEE Sentinel-2 Active Fire Detection - conditional image composition

I am working on Sentinel-2 image fire detection in Google Earth Engine. I would like to apply the Custom Scripts Active Fire Detection algorithm (https://github.com/sentinel-hub/custom-scripts/tree/...
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Why can’t I apply Otsu’s threshold on a “large” raster image in QGIS?

I have some rasterimages and need to find a threshold to separate vegetation from ground. As I am very unfamiliar with python and not used to write/read code, I followed the openCV tutorial and ...
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Smoothing layer after masking on Google Earth Engine

I'm working with RADD alerts and I'm trying to apply temporal filters to the image. That way: Script: https://code.earthengine.google.com/eda2cd15ca30478bf6e5d4104b57fc39 // Getting the latest alert. ...
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Why is my image not showing and in my metadata it says that my band is 0?

I'm working on estimation chlorophyll-a using a Landsat 8 image on Google Earth Engine but my image is not showing, and in my metadata it says that my band is 0. I'm really really confused because I'...
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How do you check the attribute information of the tif image in QGIS?

Where can I check the brightness value (DN) of the image stored as 'tif format' in QGIS? What is the way to add it to the attribute table? Current progress: Coordinates are assigned to each pixel of ...
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Is ground sampling distance (GSD) related to the sampling of the object we have on the ground or to the output that comes from the sensor?

I am studying the GSD for a remote sensing mission. I don't understand if the GSD is related to the sampling of the analog output generated by a sensor or to a given scene on the ground. My textbook ...
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I want to make sure that the two images match in the ENVI program

Is there a function that can compare pixels and brightness values of two satellite images in the ENVI program? I want to make sure that the two images match numerically or histogram. There are two ...
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Isolating & exporting one band of an image in GEE

I am trying to export images from the "Tsinghua FROM-GLC Year of Change to Impervious Surface" data set. I want to isolate and export one year (i.e. 1990); however output keeps adding the ...
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Google Earth Engine Exported GeoTIFF is blank - how to export my code as an RGB for Ai or Ps

I am trying to export my classified map layer (classified_image) as a GeoTIFF, JPG or PNG (Any format that can be viewed on Illustrator or Photoshop). Geolocation does not matter, I just need the ...
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Landsat 8 Collection 2 (C2) Level 2 Science Product (L2SP)

I am exploring data sources for land surface temperatures (LST) for summer 2021. From Landsat 8 Collection 2 Surface Temperature (https://www.usgs.gov/core-science-systems/nli/landsat/landsat-...
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Finding the correct aspect ratio from image

I'm trying to put an image over my map. I know the correct bounding box of it, but when I load it, I see it doesn't fit correctly in the map. Just for curiosity, I cut a piece of map of same region ...
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How to change image background value to zero in ENVI

I have two tiff images with the same background value of 2568.768956. I tried to mosaic them using ENVI and specified the "ignore value" as 2568.768956. However, ENVI automatically rounds ...
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How to remove black stripe on hyperspectral image band?

I saved individual bands from a hyperspectral image and saw that some bands have this big black stripe that run from bottom to the top of the image. I tried applying some filters available on ENVI and ...
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Classifying RBG image to create favourability raster or vector using ArcMap

I have a scanned map (RBG) as seen below and would like to digitize it to a raster or shapefile in order to categorize the coloured map. I have tried Reclassify raster, however you need to use a ...
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QGIS: Shifting ortophotos by some meters to equalize the mismatch/offset/incongruence with satellite imagery

I got several true ortophotos from environmental authorities. These photos should serve as reference for classifying pixels of satellite records. Though the authorities told me that the georeferencing ...
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1 answer
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Export image from GEE without accidental resample?

I'm trying to export an ALOS DSM raster at its native 30m resolution for a specific region derived from a centroid in GEE. I'm noticing, however, that when I open the raster in ArcGIS there is a clear ...
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Correcting effect of solar elevation angle in tagged areas for Landsat 8 L1T images using ENVI

Someone said the L1T images did not correct the effect of solar elevation angle. I want to know how can I get the parameters for doing such correction in ENVI?
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2 answers
181 views

Google Earth Engine: "Parameter 'index' is required" error when mapping to an Image Collection

I am trying to apply a distance function to a collection of masked images, but am receiving a "Parameter 'index' is required" error. I've found answers for other "Parameter 'xyz' is ...
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4 answers
2k views

What is lost when converting 12 bit imagery to 8 bit?

SPOT 6/7 satellite imagery is captured with a dynamic range of 12 bits per pixel per channel (ref). However almost all of the SPOT imagery I have seen in use has been 8 bits per channel, and split ...
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2 votes
1 answer
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How to remove banding in Sentinel-2 imagery over water?

In several L2A Sentinel-2 images, I've seen an angular banding effect over water bodies. Another user thought that these seam effects were caused by aerosol scattering affecting each of the S2 MSI ...
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4 answers
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Should I always choose Sentinel-2 atmospheric-corrected imagery?

Sentinel-2 imagery is available in the default L1C form, or in the atmospheric-corrected L2A form. I haven't been able to find a L1C - versus - L2A comparison that would provide the pros and cons of ...
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2 votes
1 answer
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Generate list of legend's RGB colors and values in ArcGIS

I am writing a node/typescript app that analyzes raster data. It uses leaflet and esri-leaflet quite a bit (modified to work server-side). For a given map bounds, it can download a raster image from ...
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4 votes
1 answer
356 views

Generating Hough transform (Hough line transformation) of binary image using QGIS

How do I generate a Hough transform (Hough line transformation) of a binary image in QGIS? I tried in GRASS and I got Error: unable to fetch interface description for command I found from the link: ...
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Applying Otsu thresholding method to raster in QGIS

How can I apply Otsu’s threshold method to a Raster in QGIS for reduction of a gray level image to a binary image?
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5 votes
2 answers
2k views

Computing Excess Green Vegetation Index (ExG) in QGIS [duplicate]

I have to process the image for Sugarcane row detection and extraction. Sample image is accessible from the link: https://github.com/AndresHerrera/croprows_generator_pa_v2/tree/master/droneimages I ...
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2 votes
1 answer
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Designing a Low Pass Filter

How can I design a similar Low Pass Filter as given below which takes into account only 4-connectivity and ignores the pixels that complete 8-connectivity?
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LPF and HPF filters in ENVI

Since we know about convolution filter in image processing, it is basically a matrix applied to an image and a mathematical operation comprised of integers and it works by determining the value of a ...
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1 vote
0 answers
28 views

Spectral signatures difference between a raw image and an atmospherically corrected image

I did atmospheric correction of Landsat 5 image by Quick atmospheric correction method(QUAC), now I want to compare atmospheric corrected spectral signatures from ENVI QUAC with the input spectral ...
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1 vote
1 answer
201 views

Radiance and Raw Image difference after Radiometric calibration

I have done Radiometric calibration on Envi 5.3 and got the output of my input Landsat 5 image. What is the difference between the raw image and the radiance image and why is this value of radiance ...
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Using r.thin in GRASS

I am new to GRASS GIS. I need to run my program with the r.thin command, and I will not get any results as I proceed according to the program. My map is a png image in 2 bits. How do I execute this ...
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Landsat 8 band combinations aren't appearing the way they should in ArcMap

I did all the right steps of combining 7 of Landsat 8 bands into one .tif in ArcMap but the combinations aren't just appearing the way they should, attached picture related.
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1 vote
1 answer
36 views

Mask area of GeoTIFFs surrounded by 0 Data

I've a larger amount of GeoTIFFs which basically look like: The area of interest is the rectangle in the middle. Black shows 0-Data. My goal is to fill the left and right sided areas (round) with 0-...
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2 votes
0 answers
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Statistics from one image to another in Google Earth Engine

I now have two images of the same place, image1 stores image values and each pixel on image 2 stores time (jday).I want to count the sum of image values of image1 at the same time point on image2.For ...
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1 answer
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Combining single cloud-masked images using Google Earth Engine

I am trying to calculate the mean pixel values of three Sentinel-2 images, all of which I have cloud masked separately. They all have small areas of cloud but in different places. I assumed that when ...
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-1 votes
1 answer
241 views

Problem Visualizing and Downloading LANDSAT 5 Images With Google Earth Engine

I am new to GEE. I'm working with Landsat images. First, visualizing them in the map, then downloading them and working with them afterwards in QGis 3.6 to obtain certain indexes (NDVI, NDWI, Wetness) ...
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Increasing Resolution of Image By Splitting Image Pixel into Smaller Pixels | Google Earth Engine?

I have two MODIS satellite images with same custom band, one of 1000m/px resolution and other of 250m/px. I want to compute their mean 'image' and display as map layer. My current way of achieving ...
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Pixel-based image classification (Orthoimage or Raw image?

I am studying image classification and wanted to produce some land cover maps. However, i can not seem to find resources that states whether you need to geometrically correct (orthorectification) your ...
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1 vote
1 answer
158 views

Orfeo toolbox batch processing

I want to process Sentinel 2A images using another tool that is not SNAP. The later is very slow and crashes each time. I was recommended the Orfeo toolbox. I installed it on QGIS. I have 58 S2A ...
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1 answer
54 views

Band Compositing

This is probably a trivial question, but is it possible to create band composites using bands of different resolutions (10m, and 20m)? I tried that and exported the resulting rasters to JPEG and it ...
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1 answer
183 views

Image (band) interpolation

I have a set of sentinel 2A images. I eliminated those that contained too many clouds, and then I created a cloud mask using cloud probabilities and Otsu thresholding method to eliminate cloudy pixels ...
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1 vote
0 answers
64 views

Rasterio doesn't display the differnet bands of image

I have one raster which has three different bands. The two first bands look like this (in qgis): and the third band looks like this ( missing values in some places: The three bands sit on top of ...
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-2 votes
1 answer
79 views

Processing and classifying satellite images using Python [closed]

I wish to process and classify Sentinel2-L2A images using solely Python (Google Colab). Is it possible to do such a thing, and if so, what libraries should I use?
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1 answer
813 views

"Spatial join" between raster and shapefille- give raster the shapefile values with python

I have raster which has NDVI values .In addition, I have shapefile(geopandas) on top of this raster but it doesn't fully covers the raster (illustration): the shapefile has column which contain data ...
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2 answers
52 views

Transforming featureCollection back to an actual image

I am about to finish my calculations made on the feature that I have extracted from NDVI images. Each image was originally transformed into a list (by the scale of 10) and extracted to a CSV file. One ...
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1 answer
188 views

Using the pixel quality layers of the Landsat SR products to create cloud and water masks in R

I tried to use the RStoolbox package function classifyQA to generate information on quality of the layers of interest, namely - cloud, cloud shadows, and water. I am unable to understand how to mask ...
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81 views

Why is my bands showing black after atmospheric correction using SCP plugin(DOS1) in QGIS or DOS in Erdas?

I am classifying Landsat TM and Landsat ETM (level 1) scenes for my study area as part of my research(LU/LC). The scenes are in a single tile and span 5 different timelines. I have done the ...
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5 votes
2 answers
500 views

"Copy" Image coordinates to another image that is nd.array

I have image with three bands. I have script predicts the first band pixels values by using the two other bands and in the end generates an image.The generated image is at the beginning pandas table, ...
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  • 1,797
3 votes
1 answer
180 views

Calculate new band for satellite image after predict values with RF

I have satellite image which contains 3 different bands. I'm using Python (jupyter notebook) in order to calculate new band by applying random forest regression. My problem is that after I have ...
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7 votes
2 answers
4k views

Create pandas DataFrame from raster image - one row per pixel with bands as columns

I have a raster image with 3 bands. I would like to convert this image to a csv file where each row will be one pixel and each column will be one band, so that I can easily see the three values each ...
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