Develop Reference

How do I check if mutiple YOLO item overlap each other

i need your help,and sorry about my poor English.
I using YOLOv4 to get detection object.
yolov4 can get object like cars, motorcycles, buses, etc.
and I want to using the result to check if car accident happen.
my perspective:
i think can check the all object in image
and try to detect whether two objects overlap.
And start to calculate the time at the same time.
If the two objects overlap for more than a period of time, it is judged as a car accident.
Describe the problem:
does anyone know how to check if the multiple Rectangle if overlap each other
i try to using that in C#
for (int i = 0; i < itemRectCar.Count - 1; i++)
{
if (itemRectCar[i].IntersectsWith(itemRectCar[i + 1]))
{
rectangle3 = Rectangle.Intersect(itemRectCar[i], itemRectCar[i + 1]);
itemRectCar[i].Intersect(itemRectCar[i + 1]);
if (!itemRectCar[i].IsEmpty)
{
graphics.DrawRectangle(penRed, rectangle3);
}
}
}
but this method only can work in a image can't be work in video
image
I need someone to inspire me.
thank you read my problem,hope you have a nice day

I think your issue is that you check car 1 vs car 2, car 2 vs car 3 etc. But what you don't do is to check car 1 vs car 5, or car 2 vs car 8
You basically want to check a collision of one car for all the other cars in the array, then you take the next car, and check for a collision with all other cars and so on.
To do that, you need a nested loop:
for (int i = 0; i < itemRectCar.Count; i++)
{
for (int j = 0; j < itemRectCar.Count; j++)
{
// A car shouldn't collect with itself, so skip this case
if (i == j)
continue;
if (itemRectCar[i].IntersectsWith(itemRectCar[j]))
{
rectangle3 = Rectangle.Intersect(itemRectCar[i], itemRectCar[j]);
itemRectCar[i].Intersect(itemRectCar[j]);
if (!itemRectCar[i].IsEmpty)
{
graphics.DrawRectangle(penRed, rectangle3);
}
}
}
}

Custom Queue Class Iteration and Data Retrieval C#

So I'm working in Visual Studio 2015 with a few custom classes. One of which is called MinPriorityQueue, and it is a priority queue that, in this situation, allows me to retrieve the object of MinimumPriority in the queue via a property MinimumPriority. There is also a method called RemoveMinimumPriority, which is self-explanatory.
I am not allowed to modify this method, it was pre-made for us for this assignment, otherwise I would have already found a simple solution.
My program is meant to compare two text files, and return a value based off a certain equation which isn't important as far as this post goes. The problem I am having is within my UserInterface code. Here is my click event for the 'Analyze' button on my GUI.
private void uxAnalyze_Click(object sender, EventArgs e)
{
Dictionary<string, StoreWord> dictionary = new Dictionary<string, StoreWord>();
const int _numFiles = 2;
MinPriorityQueue<float, StoreInfo> minQueue = new MinPriorityQueue<float, StoreInfo>();
int numWords1 = 0;
int numWords2 = 0;
//Process Both Input Files
using (StreamReader sr = new StreamReader(uxTextBox1.Text))
{
for (int i = 0; i < _numFiles; i++)
{
if (i == 0)
{
dictionary = ReadFile(dictionary, uxTextBox1.Text, i, out numWords1);
}
if (i == 1)
{
dictionary = ReadFile(dictionary, uxTextBox2.Text, i, out numWords2);
}
}
}
int[] numWords = new int[2];
numWords[0] = numWords1;
numWords[1] = numWords2;
//Get 50 Words with Highest Combined Frequencies
foreach(var entry in dictionary.Values)
{
StoreInfo freq = new StoreInfo(entry, numWords);
minQueue.Add(freq, Convert.ToSingle(entry[0] + entry[1]));
if(minQueue.Count > 50)
{
minQueue.RemoveMinimumPriority();
}
}
//Compute and Display the Difference Measure
float diffMeasure = 0;
float temp = 0;
foreach( x in minQueue)
for (int i = 0; i < minQueue.Count; i++)
{
temp += minQueue.????; //This is where my problem stems
}
diffMeasure = (float)(100 * Math.Sqrt(temp));
}
A few lines from the end you will see a comment showing where my problem is located. The MinPriorityQueue (minQueue) has two parameters, a Priority, and a Value, where the Priority is a Float, and the Value is another class called StoreInfo. This class has an Indexer, which will return information from a different file depending on what the index is. In this case, there are only two files. For example: StoreInfo[i] returns the frequency of a word in the ith text file.
Ideally, my code would look like this:
for (int i = 0; i < minQueue.Count; i++)
{
temp += (minQueue.minimumValue[0] - minQueue.minimumValue[1])*(minQueue.minimumValue[0] - minQueue.minimumValue[1]);
}
diffMeasure = (float)(100 * Math.Sqrt(temp));
Problem is, that would require a minimumValue property, which I don't have access to. All I have is minimumPriority.
As far as I can see, there is no other way for me to get the Values that I need in order to get the frequencies that I need to get from the indexer and put into the equation.
Help is much appreciated.

Alright guys, I've been thinking at this for far too long, and it doesn't seem like anyone else sees another solution either.
At this point, I'm just going to go with the logical solution and add another property into the MinPriorityQueue class, even though it is against my professor's wishes.
Thank you all anyway.

Comparing char arrays method

I've been playing space engineers which has been epic since they added in-game programming, I'm trying to make a gps auto-pilot navigation script and have to get the block positions finding the blocks by name looking for a smaller string within their bigger string name. I wrote this method to find a small string (word) in a larger string (name of the block):
bool contains(string text, string wordInText)
{
char[] chText = text.ToCharArray();
char[] chWord = wordInText.ToCharArray();
int index = 0;
for(int i = 0 ; i < chText.Length - chWord.Length ; i++)
for(int j = 0; j < chWord.Length;j++,index++)
if (chWord[0] == chText[i])
index = i;
else if (chWord[j] == chText[index]){}
else if (index == chWord.Length-1)
return true;
else break;
return false;
}
Am I even doing it right, should I be doing it another shorter way?

This is simple with .Contains() which returns a bool.
text.Contains(wordInText);

If you simply want to check if a string contains an other string, then you can use string.Contains, the string class already provides a bunch of methods for string operations.

As already mentioned, the String class already has a Contains method that should give you what you need.
That said, your code doesn't work. I can see where you're going with it, but it's just not going to work. Stepping through it in a proper dev environment would show you why, but since this is more in the way of a script that's probably not an option.
So... the basic idea is to iterate through the string you're searching in, looking for matches against the string your searching. Your outer for statement looks fine for this, but your inner statements are a bit messed up.
Firstly, you're doing the first character check repeatedly. It's wasteful, and misplaced. Do it once per iteration of the outer loop.
Second, your exit condition is going to fire when the first character of wordInText matches the characters at index wordInText.Length in text which is not apparently what you want.
In fact you're all tripped up over the index variable. It isn't actually useful, so I'd drop it completely.
Here's a similar piece of code that should work. It is still much slower than the library String.Compare method, but hopefully it shows you how you might achieve the same thing.
for (int i = 0; i <= chText.Length - chWord.Length; i++)
{
if (chText[i] == chWord[0])
{
int j;
for (j = 0; j < chWord.Length; j++)
{
if (chText[i + j] != chWord[j])
break;
}
if (j == chWord.Length)
return true;
}
}
return false;

Using a string in place of an object when accessing it

First off I'm sure that I am using the wrong terminology here but I will fix it if someone comments on it. Please be gentle.
So I have multiple charts on a page and I am performing virtually identical actions on each. For demonstrative purposes lets call my charts something like: chart1, chart2, ..., chartn where n is somewhere in the vicinity of 20. What I would like to do is drop this in a for loop and perform all the work in one smaller chunk of code, especially if I have to tweak it later.
So my question is whether or not I can vary the n part representing the object (terminology?) so I can get this done more efficiently.
i.e.:
for(int i = 0; i < 20; i++)
{
String chartName = "chart" + i;
chartName.Series.Clear();
}
I have a feeling you can't do this with a string so I was looking into doing a foreach but I don't know how to do this with charts.
Thanks a lot!

You should put the charts in a list. For example, this makes a list of Chart objects (or whatever your chart type is):
List<Chart> charts = new List<Chart>();
Then you can add charts:
charts.Add(new Chart());
And use them:
for (int i = 0; i < charts.Count; i++)
{
charts[i].Series.Clear();
}
Of course, you can make the charts variable a field in your class.
You can directly initialize a list (or array, or dictionary1) like this:
List<Chart> charts = new List<Charts>()
{
new Chart(),
new Chart(),
existingChart1,
existingChart2
};
Or, if you create a new array of objects using that syntax...
Chart[] arrayOfCharts = new []
{
new Chart(),
new Chart(),
existingChart1,
existingChart2
};
...then you can add multiple objects at once using AddRange:
charts.AddRange(arrayOfCharts);
1) You can use this so-called collection initializer syntax on any object that has a public Add method.

Can you access your chart from a list/array/collection of charts like this?
for (int i = 0; i <= 19; i++) {
String chartName = "chart" + i;
Charts(chartName).Series.Clear();
}
or maybe
for (int i = 0; i <= 19; i++) {
String chartName = "chart" + i;
Charts(i).Series.Clear();
}

Errata in Extreme Programming Adventures in C#?

I'm trying to work my way through Ron Jeffries's Extreme Programming Adventures in C#. I am stuck, however, in Chapter 3 because the code does not, and cannot, do what the author says it does.
Basically, the text says that I should be able to write some text in a word-wrap enabled text box. If I then move the cursor to an intermediate line and hit enter, the code should re-display the lines before the cursor, add a couple of lines and a set of HTML paragraph tags, then append the rest of the lines. The code doesn't match the text because it uses the textbox.lines property. Well, no matter how many word-wrapped lines there are in a text box, there's only ONE line in the Lines property until you hit a carriage return. So, the statement that the code should, "Copy the rest of the lines into the buffer" appears wrong to me.
I'd appreciate anybody having experience with the book telling me what I'm reading, or doing, wrong!
Thanks.
EoRaptor

Try emailing Ron Jeffries directly. I have the book - somewhere, but I don't remember it not working. His email address is ronjeffries at acm dot org and put [Ron] in the subject line.
(And for those wondering - his email info was right from his website Welcome page)

I've also just started this book and had exactly the same problem although the code you have included looks further along than where I am.
The 'subscript out of range' occurred for 2 reasons, first as Ron explains he was just testing and so returned a hard-coded value of 3 before he wrote the CursorLine() function, which means you I think at least 4? lines of text which as you say need to be pasted in, or maybe set the text to this value before running, also as you say they need to have carriage returns to make txtbox.Lines return an array of strings.
The second reason occurs even after CursorLine() has been implemented but only happens if the text box is empty as txtbox.Lines returns string[0] but I think Ron is implementing a 'User Story' which says that when text has been entered and user presses enter, so not sure if he fixes this later, but will probably find out!
The author's do state that they are learning C# and will show the development wart's and all, which is one of the reasons I have chosen to study this book as I think it is encouraging me to develop projects. I also try to do the code first before looking at his solutions to see if I'm thinking the same way, but maybe I know C# a little better than I give myself credit for, or I'm completly crap, but I've noticed a few things, first he says that overriding OnKeyDown() doesn't work, but I think he must have got confused and tried to do in Form, instead of deriving from TextBox and overriding there.
This was my code when reading the 'User Story':
int curPos = txtbox.SelectionStart;
string Wrd = Environment.NewLine + "<P></P>" + Environment.NewLine;
txtbox.SelectedText = Wrd;
int pl = Environment.NewLine.Length + 3; // "<P>" length is 3
// Put text cursor inbetween <P> tags
txtbox.SelectionStart = curPos + pl;
It works differently to Ron's code, but was just my interpretation of the 'User Story' and not sure how should act if text is selected or wether to split line if text cursor in the middle etc.
Also in 'My Adventures' in Extreme Programming Adventures in C#
txtbox.GetLineFromCharIndex(txtbox.SelectionStart)
gets the cursor line position and doesn't matter if no carriage returns or resized,
as far as I can tell, I done little test with:
txtbox.GetLineFromCharIndex(txtbox.TextLength)
which returns the total amount of lines, which will vary if you resize the text box.
Using C# I always look for solutions which already exsist and people may slate me for this but I think MS have created a great language with great components which do what you expect them to do, so don't have to re-create the wheel each time.
Although like I say it's early days in this book and perhaps these simple solutions aren't extensible enough and maybe Ron's taking that into account, although he did mention just get it working then worry about that later is more the XP way.
Warren.

print("using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
namespace NotepadOne {
public class TextModel {
private String[] lines;
private int selectionStart;
private int cursorPosition;
public TextModel() {
}
public String[] Lines {
get {
return lines;
}
set {
lines = value;
}
}
public int SelectionStart {
get {
return selectionStart;
}
set {
selectionStart = value;
}
}
public int CursorPosition {
get {
return cursorPosition;
}
set {
cursorPosition = value;
}
}
public void InsertControlPText() {
lines[lines.Length - 1] += "ControlP";
}
public void InsertParagraphTags() {
int cursorLine = CursorLine();
String[] newlines = new String[lines.Length + 2];
for (int i = 0; i <= cursorLine; i++) {
newlines[i] = lines[i];
}
newlines[cursorLine + 1] = "";
newlines[cursorLine + 2] = "<P></P>";
for (int i = cursorLine + 1; i < lines.Length; i++) {
newlines[i + 2] = lines[i];
}
lines = newlines;
selectionStart = NewSelectionStart(cursorLine + 2);
}
private int CursorLine() {
int length = 0;
int lineNr = 0;
foreach (String s in lines) {
if (length <= SelectionStart && SelectionStart <= length + s.Length + 2) {
break;
length += s.Length + Environment.NewLine.Length;
lineNr++;
}
lineNr++;
}
return lineNr;
}
private int NewSelectionStart(int cursorLine) {
int length = 0;
for (int i = 0; i < cursorLine; i++) {
length += lines[i].Length + Environment.NewLine.Length;
}
return length + 3;
}
}
}
");
The InsertParagraphTags method is called by pressing the enter key in the textbox.
BTW, the break here is that there is a subscript out of range error if you try to hit enter at the end of the text. I'm sure I could figure out how to get around this but then my code won't look like his code; which is what I'm trying to learn.
Randy