Why gdal.open(path).ReadAsArray() produce different results from tiffile.imread(path) - arrays

Since colab won't allow me to use tiffile.imread() by giving error 'ValueError: <COMPRESSION.LZW: 5> requires the 'imagecodecs' package', I use gdal.open().ReadAsArray() to read tif file and generate input data for model to inference. This results in:
When I use tiffile.imread() to read the same tif.file in another platform and created input with the same procedures as above. The model prediction finally goes to:
The results from the second image makes sense for the classes I want to predict. I just want to the reason that caused this difference. It seems gdal changed the order of pixels?

This finally works for me. Since I cannot use tiffile.imread() in colab, I tried gdal and rasterio, but the image shape would be channel first. The problem for the first figure is caused by
np.reshape()
which did not change the axis of data dimension.
Then I used codes below and the issue is addressed.
with rio.open("gdrive/My Drive/file.tif") as ds:
arr=ds.read()
np.moveaxis(arr, 0, -1)

Related

GradCam Implementation in TFJS

I'm trying to implement GradCam (https://arxiv.org/pdf/1610.02391.pdf) in tfjs, based on the following Keras Tutorial (http://www.hackevolve.com/where-cnn-is-looking-grad-cam/) and a simple image classification demo from tfjs, similar to (https://github.com/tensorflow/tfjs-examples/blob/master/webcam-transfer-learning/index.js) with a simple dense, fully-connected layer at the end.
However, I'm not able to retrieve the gradients needed for the gradcam computation. I tried different ways to retrieve gradients for the last sequential layer, but did not succeed, as types of tf.LayerVariable from the respective layer is not convertible to the respective type of tf.grads or tf.layerGrads.
Did anybody already succeeded to get the gradients from sequential layer to a tf.function like object?
I'm not aware of the ins and outs of the implementation, but I think something along the lines of this: http://jlin.xyz/advis/ is what you're looking for?
Source code is available here: https://github.com/jaxball/advis.js (not mine!)
This official example in the tfjs-examples repo should be close to, if not exactly, what you want:
https://github.com/tensorflow/tfjs-examples/blob/master/visualize-convnet/cam.js#L49

Meshroom: how to access the final camera parameters?

I am trying to write a script which loads the camera parameters from Meshroom and imports them into a CAD program. My first understanding was that these parameters (position, rotation matrix, focal length etc.) are contained in the JSON-file cameras.sfm in the StructureFromMotion-subdirectory.
After importing these parameters into Rhino3D and comparing the resulting views onto the 3D-mesh with the undistorted photographs in the PrepareDenseScene-directory, I find surprising large discrepancies. The mesh which was the result of the run was good, so I think that the deviation is because of the parameters in cameras.sfm being not the final ones. This assumption is also supported by the fact that the file only contains the focal length as read from the input images' EXIF information and no refined values. So my question is:
How can I access the final camera parameters from the output of Meshroom?
Knowing this would help me a lot for re-building a photogrammetry/CAD pipeline I had previously implemented for VisualSFM + CMPMVS.
Many thanks!
EDIT: As this is my first post, I am not able to create a new tag for Meshroom. Perhaps this could be added by someone else? Thanks!

setting sampling time in c mex s func

What is the equivalent of the following for a C-mex s function? That is, how do I set discrete sample time of a block to the top level fixed step size in C?
My problem is, I could not find a way to "get" the top level fixed step size parameter in C-mex.
function setup(block)
block.SampleTimes = [str2double(get_param(bdroot, 'FixedStep')) 0];
Use ssGetFixedStepSize to get the base rate of the model. You may also want to ssSetErrorStatus if the that call returns 0, because that means your model is not configured with a FixedStep solver.
If, for some reason, you really want to go about fetching the information similar to what you have in the question, then you might be able to get access to it if you dig through the SimStruct pointer's fields. To do this, breakpoint in the mex file using a debugger and watch that variable.
Another option would be a few mexCallMATLAB calls to get the information you want.

Cannot plot in Matlab. It says my matrix is empty. Weird?

Doing some simple plotting and I cannot seem to figure out why I can't plot my data. I troubleshooted it first by checking to see if I had any data in my arrays first. I did not!! I'm completely lost on how to fix this.
I also tried creating a script to see if maybe it solved the issue instead of using the command window. I still get the same error.
Code:
t=0:1e-6:((2e-3-1e-6)-1);
vm=sin(2*pi*1e3*t);
vc=sin(2*pi*20e3*t);
vdsb=vc.*vm;
plot(t,vdsb,'b')
You probably don't want that last -1 in your code setting up t. Try changing t to:
t=0:1e-6:((2e-3-1e-6));
Or, if you really want it negative, you need to change the step size to negative:
t=0:-1e-6:((2e-3-1e-6)-1);
Otherwise, t is defined from 0:psotiveStep:negativeNumber and so it is empty.

Easy way to plot and display arrays?

First post here. Using C in Visual Studio 2008. Can work with VS 2005 if necessary.
How do I display numerical data in arrays as in a spreadsheet?
How do I plot numerical data in arrays?
These seem to be simple questions. But I cannot find solutions. So far, I would print the data to a file, import into Excel and view/plot. However, with this code there are too many arrays--so the print/import/plot is tiring.
Some constraints.
I do not want to write 20+ lines of code to do the above. MATFOR or Array Visualizer let you do the plotting with a one line function call.
They cannot display the data in a convenient format. I would like to display the data and the plot in one or two windows so that they are visible simultaneously.
This is a win32 console application---all the code is portable.
Will be using these during debugging.
Free or paid.
While I am looking for something specific, the requirements are substantially the same for any one doing numerical work with arrays and matrices--displaying data and plot simultaneously.
I am hoping that a such a tool has been written and is available.
I am also open to a solution that outputs the array data to an Excel sheet (can keep Excel open) and if it can also plot that can be great but I can live without plotting.
PS: I need this only when debugging the code.
I use ArrayDebugView which is a plug-in you install in Visual studio and draws graphs out of arrays while you are debugging your application. It works as a visual way of variable watch in debug mode. You don't need to write a line of code.
I can't think of any library that would enable what you want in a console app in less than 20 lines of code. My suggestion would be instead to script the plotting-step using MATLAB og GNU Octave to do the actual plotting.
In order to display numerical data in array, you should add the pointer to the first data element you want to observe, into the watch --- if you want to observe the array from the beginning, it would just be the array name, which is the pointer to the first element. In order to view more then one element, you add a "," after the pointer, followed by the number of element you want to observe.
For example, in order to observe the elements of float farray[100];, you should add to the watch farray,100.
In order to plot, you can copy-paste from the watch to your plotting software (i.e. excel), but it is not very convenient as you cannot copy the data column alone, but the columns to the left and right as well, so it involves extra manual editing.
I use GNUPlot (http://www.gnuplot.info/) to display my performance/speedup measurements.
I print my numbers to stdout and wrote a bash script that combines these numbers and calls gnuplot for rendering.
I made a simple plotting program for that purpose. There is only a textbox where I paste the data and a chart where it's drawn.
The data needs to be in either form:
with an automatic X (increment by 1 for each value): seriesName value
for both X and Y specified: seriesName xvalue yvalue
Most of the time I used to plot data from tracepoints.
I copy/paste the whole output window of VS, the plotting program ignores anything that doesn't follow these 2 forms (so I don't have to cleanup the string and put it in excel and all).
It does line, point, colum, area charts and save image, copy to clipboard.
MiniPlot
There are several ways to do this but this will require writing some code. Visualizing data is generally easy and straight forward but visualizing data exactly the way you want them to look will require some additional code and work.
There are several options to visualize data:
A combination of BASH and GNUPLOT
Use MATLAB or OCTAVE for all your calculations and visualization
Use PYTHON and SciPy and matlibplot libraries.
Gnuplot is a great tool to plot data but it is cumbersome to use. It looks fabulous if you invest time to get the plots right and combines excellent with LaTeX and has a good fit implementation for arbitrary functions. Visit http://gnuplot-tricks.blogspot.ch/ great site to learn all about gnuplot.
Numerical programs such as MATLAB and it's open source equivalent OCTAVE are great because they are fast implementation languages for numerical programs and have extensive additional libraries especially MATLAB. For high load numerical computing it is really slow and the plot library is only good for basic plotting needs.
Using PYTHON and its scientific programing libraries (SciPy and matlibplot) are a great combination. This allows excellent plot which are not as cryptic as gnuplot to plrogram and it is more flexible than MATLAB in plotting. Additionally it gives you a environment for numerical programing like MATLAB.

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