I am working on a vb.net auto-focus routine and have the image processing part worked out, basically I do some edge detection, convert to gray-scale and then measure the standard deviation to work out the most 'in focus' point of the image.
I have done this with a number of images, and it almost comes out as a normal distribution, now I want to start to integrate this with my microscope and a stepper motor.
The concept is that I would move through a lower and upper limit on the stepper motor, and measure the above through live-view, recording the values in a list. In my case the two things I want to record are the position, and the double standard deviation value.
I am wondering what the best way to record these are, should it be
recorded as a typed list, or a dictionary or another method?
Once I record all of these values, I would want to go through the values to conduct some simple analysis of them, so if that was the case
how would I then be able to determine the average, min, max etc?
My first attempt of storing the information was in a typed list, where I had essentially done the below;
Public ZPositions As New List(Of Zfocus)
Public Class Zfocus
Public Position As Integer
Public GreyStDev As Double
End Class
The second way was to use a dictionary;
Public ZPosition As New Dictionary(Of Integer, Double)
However in both cases, I am not sure how I can either pull out a single maximum position value (e.g. Position integer,) or from the dictionary the position value (integer) which (sort of) corrosponds to the best auto-focus position.
The Third added bonus, is to be able to pull out any postions above a
specific value, which may corrospond to having some focus information
within them for focus stacking?
Many thanks
Big thanks to jmcilhinney, this solved my issue and works a treat!
Went with a strongly typed list (the ZFocus list) and then I could do the below;
MaxPosition = ZPositions.First(Function(zp1) zp1.GreyStDev = ZPositions.Max(Function(zp2) zp2.GreyStDev))
This allowed be to set up an auto-focus routine which loops through a number of images (as a test), stores the position (e.g. image number in this case) and the intensity edge information, and at the end then pull out the strongest intensity information which forms the best auto-focus point in my case
Related
So basically im doing this for my minecraft spigot plugin (java). I know there are already some land claim plugins but i would like to make my own.
For this claim plugin i'd like to know how to get if a point (minecraft block) is inside a region (rectangle). i know how to check if a point is inside a rectangle, the main problem is how to check as quickly as possible when there are like lets say 10.000 rectangles.
What would be the most efficient way to check 10.000 or even 100.000 without having to manually loop through all of them and check every single rectangle?
Is there a way to add a logical test when the rectangles get generated in a way that checks if they hold that point? In that case you could set a boolean to true if they contain that point when generated, and then when checking for that minecraft block the region (rectangle) replies with true or false.
This way you run the loops or checks when generating the rectangles, but when running the game the replies should happen very fast, just check if true or false for bool ContainsPoint.
If your rectangles are uniformly placed neighbors of each other in a big rectangle, then finding which rectangle contains point is easy:
width = (maxX-minX)/num_rectangles_x;
height = same but for y
idx = floor( (x - minX)/width );
idy = floor( (y - minY)/height );
id_square = idx + idy*num_rectangles_x;
If your rectangles are randomly placed, then you should use a spatial acceleration structure like octree. Then check if point is in root, then check if point is in one of its nodes, repeat until you find a leaf that includes the point. 10000 tests per 10milliseconds should be reachable on cpu. 1 million tests per 10ms should be ok for a gpu. But you may need to implement a sparse version of the octree and a space filling curve order for leaf nodes to have better caching, to reach those performance levels.
The requirements:
100k lines
One of the columns is not text - its custom painted with wxDC*.
The items addition is coming from another thread using wxThreadEvent.
Up until now I used wxDataViewListCtrl, but it takes too long to AppendItem 100 thousand time.
wxListCtrl (in virtual mode) does not have the ability to use wxDC* - please correct me if I am wrong.
The only thing I can think of is using wxDataViewCtrl + wxDataViewModel. But I can't understand how to add items.
I looked at the samples (https://github.com/wxWidgets/wxWidgets/tree/WX_3_0_BRANCH/samples/dataview), too complex for me.
I cant understand them.
I looked at the wiki (https://wiki.wxwidgets.org/WxDataViewCtrl), also too complex for me.
Can somebody please provide a very simple example of a wxDataViewCtrl + wxDataViewModel with one string column and one wxDC* column.
Thanks in advance.
P.S.
Per #HajoKirchhoff's request in the comments, I am posting some code:
// This is called from Rust 100k times.
extern "C" void Add_line_to_data_view_list_control(unsigned int index,
const char* date,
const char* sha1) {
wxThreadEvent evt(wxEVT_THREAD, 44);
evt.SetPayload(ViewListLine{index, std::string(date), std::string(sha1)});
wxQueueEvent(g_this, evt.Clone());
}
void TreeWidget::Add_line_to_data_view_list_control(wxThreadEvent& event) {
ViewListLine view_list_line = event.GetPayload<ViewListLine>();
wxVector<wxVariant> item;
item.push_back(wxVariant(static_cast<int>(view_list_line.index)));
item.push_back(wxVariant(view_list_line.date));
item.push_back(wxVariant(view_list_line.sha1));
AppendItem(item);
}
Appending 100k items to a control will always be slow. That's because it requires moving 100k items from your storage to the controls storage. A much better way for this amount of data is to have a "virtual" list control or wxGrid. In both cases the data is not actually transferred to the control. Instead when painting occurs, a callback function will transfer only the data required to paint. So for a 100k list you will only have "activity" for the 20-30 lines that are visible.
With wxListCtrl see https://docs.wxwidgets.org/3.0/classwx_list_ctrl.html, specify the wxLC_VIRTUAL flag, call SetItemCount and then provide/override
OnGetItemText
OnGetItemImage
OnGetItemColumnImage
Downside: You can only draw items contained in a wxImageList, since the OnGetItemImage return indizes into the list. So you cannot draw arbitrary items using a wxDC. Since the human eye will be overwhelmed with 100k different images anyway, this is usually acceptable. You may have to provide 20/30 different images beforehand, but you'll have a fast, flexible list.
That said, it is possible to override the OnPaint function and use that wxDC to draw anything in the list. But that'll get difficult pretty soon.
So an alternative would be to use wxGrid, create a wxGridTableBase derived class that acts as a bridge between the grid and your actual 100k data and create wxGridCellRenderer derived classes to render the actual data onscreen. The wxGridCellRenderer class will get a wxDC. This will give you more flexibility but is also much more complex than using a virtual wxListCtrl.
The full example of doing what you want will inevitably be relatively complex. But if you decompose in simple parts, it's really not that difficult: you do need to define a custom model, but if your list is flat, this basically just means returning the value of the item at the N-th position, as you can trivially implement all model methods related to the tree structure. An example of such a model, although with multiple columns can be found in the sample, so you just need to simplify it to a one (or two) column version.
Next, you are going to need a custom renderer too, but this is not difficult neither and, again, there is an example of this in the sample too.
If you have any concrete questions, you should ask them, but it's going to be difficult to do much better than what the sample shows and it does already show exactly what you want to do.
Thank you every one who replied!
#Vz.'s words "If you have any concrete questions, you should ask them" got me thinking and I took another look at the samples of wxWidgets. The full code can be found here. Look at the following classes:
TreeDataViewModel
TreeWidget
TreeCustomRenderer
This is a bit of a long-shot. I really don't know where to ask this question.
I've been trying out CodeConnection + MakeCode with Minecraft and I haven't been able to figure out if there is correct way to place half-slabs at 0.5 step y axes increments.
I tried using a line between 2 points, but it left gaps between each slab.
If I try moving up 0.5, then it rounds it up to 1, and again leaves gaps.
It appears that all of the builder functions seem operate at a resolution of 1 block. However in-game I can obviously place slabs in 0.5 block increments to make stairs etc.
Blocks only exist at integer coordinates. Half slabs that exist in the top half of their space are still at a full integer coordinate. They just have a BlockState value of bottom=top (or top_slot_bit=true on Bedrock, represented by the integer value 8 as a bitflag, eg: 0b1... where the . bits are the integer representation of what type of slab (wood, stone, quartz...)).
What you're looking for is this widget, under Blocks:
You can set the block and then an integer representation of the desired data value (see the wiki on data values) in the numerical slot. This widget can then be dragged into the (block) portion of any block widget:
You'll probably have to some variable fiddling to get the data value to swap back and forth as you need it to, but that should solve the hurdle you've been facing.
This is more of an open discussion topic than anything else. Currently I'm storing 50 Float32 values in my NSMutableArray *voltageArray before I refresh my CPTPlot *plot. Every time I obtain 50 values, I remove the previous 50 from the voltageArray and repeat the process....always displaying the 50 values in "real time" on my plot.
However, the data I'm receiving (which is voltage coming from a Cypress BLE module equipped with a pressure transducer) is so quick that any variation (0.4 V to 4.0 V; no pressure to lots of pressure) cannot be seen on my graph. It just shows up as a straight line, varying up and down without showing increased or decreased slopes.
To show overall change, I wanted to take those 50 values, store them in the first index of another NSMutableArray *stampArray and use the index of stampArray to display information. Meanwhile, the numberOfRecordsForPlot: method would look like this:
- (NSUInteger)numberOfRecordsForPlot:(CPTPlot *)plotnumberOfRecords {
return (DATA_PER_STAMP * _stampCount);
}
This would initially be 50, then after 50 pieces of data are captured from the BLE module, _stampCount would increase by one, and the number of records for plot would increase by 50 (till about 2500-10000 range, then I'd refresh the whole the thing and restart the process.)
Is this the right approach? How would I be able to make the first 50 points stay on the graph, while building the next 50, etc.? Imagine an y = x^2 graph, and what the graph looks like when applying integration (the whole breaking the area under the curve into rectangles).
Look at the "Real Time Plot" demo in the Plot Gallery example app included with Core Plot. It starts off with an empty plot, adding a new point each cycle until reaching the maximum number of points. After that, one old point is removed for each new one added so the total number stays constant. The demo uses a timer to pass random data to the plot, but your app can of course collect data from anywhere. Be sure to always interact with the graph from the main thread.
I doubt you'll be able to display 10,000 data points on one plot (does your display have enough pixels to resolve that many points?). If not, you'll get much better drawing performance if you filter and/or smooth the data to remove some of the points before sending them to the plot.
Is there a method of using the exponent properties of LabView units for carrying custom units? For example I would find it convenient to use milli-Amperes instead of Amperes in my data wires.
My first attempt at doing so looks like this, but trying to get the value out at the end gives me nothing.
I would find it convenient to use milli-Amperes instead of Amperes in my data wires
For a wire, it's not possible, and it's not a problem, here's why:
I'm afraid what you want make little sense, since you're milli-Amperes instead of Amperes refers to representing your data, while a wire is just raw data. Adding the milli- to a floating point changes the exponent, not the mantissa, so there's no loss or gain of precision in the value that your number carries.
Now if we talk about an indicator which is technically a display of the wire value, you change the unit from "A" to "mA" to have the display you want.
Finally, in your attempt with "set numeric info", the -3 factor added next to Amperes means the unit is A^-3, not mA.
You can use data that don't use units, however than you will loose your automatic check of the units.
For display properties you can tweak the display format to show different outputs:
This format string is constructed as following:
% numeric
^ engineering notation, exponents in multiples of three
# no trailing zeros
_6 six significat digits
e scientific notation (1e1 for instance)
The prefix is the best way to affect the presentation of the value on a specific front panel.
When passing data from VI to VI, the prefix is not passed, and the data uses the base ( Amps, Volts, etc...)
In my example below, the unitless value 3 is assigned units of Amp in mA.vi. The front panel indicator is set to show units of mA.
In Watts.vi I multiply the Amps OUT of mA.vi by a constant of 9V and the result is wired to the indicator x*y.
x*y has units of W and I changed the prefix to k for presentation.
The NI forums have several threads that report certain functions (square and square root specifically) can cause unit errors or broken wires. Most folks don't even know the units capability exists, and most that do have tried and abandoned them. :)