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Showing content with the highest reputation on 10/11/2019 in all areas

  1. The first thing to do before mapping is to set up the camera parameters. Before to set up camera parameters, recommended resetting the all parameters on camera first. To set camera parameters manually need to set to manual mode. Image quality: Extra fine Shutter speed: to remove blur from photo shutter speed should be set for higher value. 1200–1600 is recommended. Higher the shutter speed reduce image quality . if there is blur in the image increase shutter speed ISO: lower the ISO higher image quality. ISO between 160–300 is recommended. if there is no blur but image quality is low, reduce ISO. Focus: Recommended to set the focus manually on the ground before a flight. Direct camera to an object which is far, and slightly increase the focus, you will see on camera screen that image sharpness changes by changing the value. Set the image sharpness at highest. (slide the slider close to infinity point on the screen you will see the how image sharpness changes by sliding) White balance: recommended to set to auto. On surveying mission Sidelap, Overlap, Buffer have to be set higher to get better quality surveying result. First set the RESOLUTION which you would like to get for your surveying project. When you change resolution it changes flight altitude and also effects the coverage in a single flight. Overlap: 70% This will increase the number of photos taken during each flight line. The camera should be capable to capture faster. Sidelap: recommended 70% Flying with higher side-lap between each line of the flight is a way to get more matches in the imagery, but it also reduces the coverage in a single flight Buffer: 12% Buffer increases the flight plane to get more images from borders. It will improve the quality of the map source: https://dronee.aero/blogs/dronee-pilot-blog/few-things-to-set-correctly-to-get-high-quality-surveying-results
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  2. I getting some images of a oil palm estate taken from a DIY drone. The image is stitch and mosaic. Has anyone done automated tree counting on these images. Seen some examples using eCognition but that was with multi-spectral images.
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  3. It might not be a very good idea to use ArcGIS but somehow we can use this software for tree counting! My method is quite simple: 1. Get a piece of hi-res image from Google Earth 2. Open the image in ArcGIS 3. Make sure toolbar "Image Classification" is checked (turned on). 4. From "Image Classification" toolbar, select "Classification" --> "Iso Cluster Unsupervised Classification" command. 5. Chose "2" for "Number of Classes" in the dialogbox. By doing it, you will have only trees (or something else similar) and non-tree objects in the result. Run it and see the result (below). C'mon, it also shows "Google Earth" trademark on the result (LOL). 6. Now go to ArcGIS ToolBox, select "Conversion" --> "From Raster" --> "Raster to Polygon". In the dialog box, check to "Simplify Polygion (optional)" checkbox. 7. The result is as below 8. Mask the area where you want to count the trees, then count the number of polygons within that mask. Bingo!!!! If you want to do it better, you can do some pre-processing steps for your image. Also, when you have the polygon layer, you can try to simplify the layer again (using Eliminate, Integrate... functions) before counting trees. Enjoy ESRI.
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  4. Oil palm tree counting is a quite simple application. You can simply use following methods: 1. Ravine extraction (Honda Kyioshi): Based on the fact that the top canopy is the brightest point. The ravine (or the valley between 2 trees) looks darker. Doing it, you wil be able to locate the central point of each tree. Then counting is some simple works to do aftewards. 2. Local threshold texture matching: Requires some programming tasks. Get the individual trees as samplings (with different sizes of canopy) and then match them over the whole image. The matching algorithm can be image correlation or histograming matching. I already did it with VB programming and it works perfectly. By doing this, you can also be able to map individual trees. All of this is based on RGB image. For better results, mask the plantation areas before running the procedure. Of course there are several other options to do. If you want to operate the procedure in an automatic way, the programming skill is needed.
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  5. look at maxmax website, they do NIR conventions on cameras that can fit on drones. Did a canon compact with them 100%. Try imageJ (free software), run the NDVI settings you will get some data. Or use a blue filter on your camera, you will get usable images for NDVI. I got good data with dessert palms from RGB images in eCognition, but you have o play with the analysis a bit! Having a NIR layer will make life easy for you. Good Luck
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  6. If you have a very-high resolution image (< 1m ) and it has only 3 spectral bands in the visible spectrum (Red, Green, Blue - RGB) with no additional infrared bands (NIR), the best option to extract trees is to use an OBIA method ( > eCognition is one of the best OBIA softwares). So, for your task, me I would use eCognition.
    1 point
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