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QUESTION
I have source (src
) image(s) I wish to align to a destination (dst
) image using an Affine Transformation whilst retaining the full extent of both images during alignment (even the non-overlapping areas).
I am already able to calculate the Affine Transformation rotation and offset matrix, which I feed to scipy.ndimage.interpolate.affine_transform
to recover the dst
-aligned src
image.
The problem is that, when the images are not fuly overlapping, the resultant image is cropped to only the common footprint of the two images. What I need is the full extent of both images, placed on the same pixel coordinate system. This question is almost a duplicate of this one - and the excellent answer and repository there provides this functionality for OpenCV transformations. I unfortunately need this for scipy
's implementation.
Much too late, after repeatedly hitting a brick wall trying to translate the above question's answer to scipy
, I came across this issue and subsequently followed to this question. The latter question did give some insight into the wonderful world of scipy
's affine transformation, but I have as yet been unable to crack my particular needs.
The transformations from src
to dst
can have translations and rotation. I can get translations only working (an example is shown below) and I can get rotations only working (largely hacking around the below and taking inspiration from the use of the reshape
argument in scipy.ndimage.interpolation.rotate
). However, I am getting thoroughly lost combining the two. I have tried to calculate what should be the correct offset
(see this question's answers again), but I can't get it working in all scenarios.
Translation-only working example of padded affine transformation, which follows largely this repo, explained in this answer:
...ANSWER
Answered 2022-Mar-22 at 16:44If you have two images that are similar (or the same) and you want to align them, you can do it using both functions rotate and shift :
QUESTION
I have this image for a treeline crop. I need to find the general direction in which the crop is aligned. I'm trying to get the Hough lines of the image, and then find the mode of distribution of angles.
I've been following this tutorialon crop lines, however in that one, the crop lines are sparse. Here they are densely pack, and after grayscaling, blurring, and using canny edge detection, this is what i get
...ANSWER
Answered 2022-Jan-02 at 14:10You can use a 2D FFT to find the general direction in which the crop is aligned (as proposed by mozway in the comments). The idea is that the general direction can be easily extracted from centred beaming rays appearing in the magnitude spectrum when the input contains many lines in the same direction. You can find more information about how it works in this previous post. It works directly with the input image, but it is better to apply the Gaussian + Canny filters.
Here is the interesting part of the magnitude spectrum of the filtered gray image:
The main beaming ray can be easily seen. You can extract its angle by iterating over many lines with an increasing angle and sum the magnitude values on each line as in the following figure:
Here is the magnitude sum of each line plotted against the angle (in radian) of the line:
Based on that, you just need to find the angle that maximize the computed sum.
Here is the resulting code:
QUESTION
Python 3.9 on Mac running OS 11.6.1. My application involves placing a plot on a frame inside my root window, and I'm struggling to get the plot to take up a larger portion of the window. I thought rcParams
in matplotlib.pyplot
would take care of this, but I must be overlooking something.
Here's what I have so far:
...ANSWER
Answered 2022-Jan-14 at 23:23try something like this:
QUESTION
How to change colors in decision tree plot using sklearn.tree.plot_tree without using graphviz as in this question: Changing colors for decision tree plot created using export graphviz?
...ANSWER
Answered 2021-Dec-27 at 14:35Many matplotlib functions follow the color cycler to assign default colors, but that doesn't seem to apply here.
The following approach loops through the generated annotation texts (artists
) and the clf tree structure to assign colors depending on the majority class and the impurity (gini). Note that we can't use alpha, as a transparent background would show parts of arrows that are usually hidden.
QUESTION
I have created a working CNN model in Keras/Tensorflow, and have successfully used the CIFAR-10 & MNIST datasets to test this model. The functioning code as seen below:
...ANSWER
Answered 2021-Dec-16 at 10:18If the hyperspectral dataset is given to you as a large image with many channels, I suppose that the classification of each pixel should depend on the pixels around it (otherwise I would not format the data as an image, i.e. without grid structure). Given this assumption, breaking up the input picture into 1x1 parts is not a good idea as you are loosing the grid structure.
I further suppose that the order of the channels is arbitrary, which implies that convolution over the channels is probably not meaningful (which you however did not plan to do anyways).
Instead of reformatting the data the way you did, you may want to create a model that takes an image as input and also outputs an "image" containing the classifications for each pixel. I.e. if you have 10 classes and take a (145, 145, 200) image as input, your model would output a (145, 145, 10) image. In that architecture you would not have any fully-connected layers. Your output layer would also be a convolutional layer.
That however means that you will not be able to keep your current architecture. That is because the tasks for MNIST/CIFAR10 and your hyperspectral dataset are not the same. For MNIST/CIFAR10 you want to classify an image in it's entirety, while for the other dataset you want to assign a class to each pixel (while most likely also using the pixels around each pixel).
Some further ideas:
- If you want to turn the pixel classification task on the hyperspectral dataset into a classification task for an entire image, maybe you can reformulate that task as "classifying a hyperspectral image as the class of it's center (or top-left, or bottom-right, or (21th, 104th), or whatever) pixel". To obtain the data from your single hyperspectral image, for each pixel, I would shift the image such that the target pixel is at the desired location (e.g. the center). All pixels that "fall off" the border could be inserted at the other side of the image.
- If you want to stick with a pixel classification task but need more data, maybe split up the single hyperspectral image you have into many smaller images (e.g. 10x10x200). You may even want to use images of many different sizes. If you model only has convolution and pooling layers and you make sure to maintain the sizes of the image, that should work out.
QUESTION
i have an import problem when executing my code:
...ANSWER
Answered 2021-Oct-06 at 20:27You're using outdated imports for tf.keras
. Layers can now be imported directly from tensorflow.keras.layers
:
QUESTION
I am trying to linearly scale an image so the whole greyscale range is used. This is to improve the lighting of the shot. When plotting the histogram however I don't know how to get the scaled histogram so that its smoother so it's a curve as aspired to discrete bins. Any tips or points would be much appreciated.
...ANSWER
Answered 2021-Nov-02 at 14:07I'm not sure if this is possible if you're linearly scaling the image. However, you could give OpenCV's Contrast Limited Adaptive Histogram Equalization a try:
QUESTION
I have create this simple env with conda
:
ANSWER
Answered 2021-Nov-06 at 19:03- The default
pkgs/main
channel forconda
has reverted to usingfreetype 2.10.4
for Windows, per main / packages / freetype. - If you are still experiencing the issue, use
conda list freetype
to check the version:freetype != 2.11.0
- If it is 2.11.0, then change the version per the solution, or
conda update --all
(providing your default channel isn't changed in the.condarc
config file).
- If it is 2.11.0, then change the version per the solution, or
- If this is occurring after installing Anaconda, updating
conda
orfreetype
since Oct 27, 2021. - Go to the
Anaconda
prompt and downgradefreetype 2.11.0
in any affected environment.conda install freetype=2.10.4
- Relevant to any package using
matplotlib
and any IDE- For example,
pandas.DataFrame.plot
andseaborn
- Jupyter, Spyder, VSCode, PyCharm, command line.
- For example,
- An issue occurs after updating with the most current updates from
conda
, released Friday, Oct 29. - After updating with
conda update --all
, there's an issue with anything related tomatplotlib
in any IDE (not justJupyter
).- I tested this in
JupyterLab
,PyCharm
, andpython
from the command prompt. - PyCharm:
Process finished with exit code -1073741819
- JupyterLab: kernel just restarts and there are no associated errors or Traceback
- command prompt: a blank interactive matplotlib window will appear briefly, and then a new command line appears.
- I tested this in
- The issue seems to be with
conda update --all
in(base)
, then any plot API that usesmatplotlib
(e.g.seaborn
andpandas.DataFrame.plot
) kills the kernel in any environment. - I had to reinstall Anaconda, but do not do an update of
(base)
, then my other environments worked. - I have not figured out what specifically is causing the issue.
- I tested the issue with
python 3.8.12
andpython 3.9.7
- Current Testing:
- Following is the
conda
revision log. - Prior to
conda update --all
this environment was working, but after the updates, plotting withmatplotlib
crashes the python kernel
- Following is the
QUESTION
I have done the following code but do not understand properly what is going on there. Can anyone explain how to fill colors in Numpy?
Also I want to set in values in a way from 1 to 0
to give spectrum an intensity. E.g-: 0 means low intensity, 1 means high intensity
ANSWER
Answered 2021-Oct-30 at 10:41First of all: The results here when I tried the code is different then what you displayed in the question.
Color MonochromaticLet's say we have a gray scaled picture. Each pixel would have a value of integers
between [0, 255]. Sometimes these values can be floats
between [0, 1].
Here 0
is black and 255
is white. The vales between (0, 255) are grays. Towards 0
it gets more gray, towards 255
its less gray.
(I'm not sure about the term Polychromatic)
Colored pixels are not so different then gray scaled ones. The only different is colored pixels storing 3
different values between [0, 255] for each Red
, Green
and Blue
values.
Now let's see what what the image you are creating is like:
Creation:You are crating a matrix of zeros with shape of: 256, 256 * 6, 3
, which is: 256, 1536, 3
.
Then with the first line you are replacing the first column with something else:
QUESTION
In my very simple case I would like to display the heatmap of the points in the points
GeoJSON file but not on the geographic density (lat, long). In the points
file each point has a confidence
property (a value from 0 to 1), how to display the heatmap on this parameter? weight=points.confidence
don't seem to work.
for exemple:
...ANSWER
Answered 2021-Nov-01 at 09:44- using your sample data for points
- these points are in Saudi Arabia, so assumed that polygons are regional boundaries in Saudi Arabia. Downloaded this from http://www.naturalearthdata.com/downloads/10m-cultural-vectors/
- polygon data is a shape file
- loaded into geopandas to allow interface to GEOJSON
__geo__interface
- dynamically filtered this to Saudi using pandas
.loc
- loaded into geopandas to allow interface to GEOJSON
- confidence data is just a straight https://plotly.com/python/mapbox-density-heatmaps/
- boundaries are https://plotly.com/python/mapbox-layers/
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