use detectnet to track two objects with same classid
hi,

i can use detectnet to get the classid, x/y coordinate… however, if there are two objects with same classid, can i distinguish the two objects? i need to track the object using the x,y coordinate. then, use the coordinates and fps to estimate the speed. (assume in horizontal direction)

thanks, …
hi,

for simplicity, you can do it by checking the bbox location directly.

but please noted that you may still need a tracker if the bbox occlusion is possible.

thanks.
one idea can be videos have frames so, vectorize each frame and calculate dtw between two consecutive frames. this will help in gaining the difference in each frame and perhaps help in classification. hope this helps you. the straight distance between two place on a map can be measured by a strip of paper and divider.use a ruler to measure the distance between the two places. if the line is quite curved, use a string to determine the distance, and then measure the string. find the scale for the map you're going to use. it might be a ruler bar scale or a written scale, in words or numbers. hint: here, we will proceed by finding out the relative speed between the two cars and then using the formula i.e., time taken$ = \dfrac{{{\text{distance travelled}}}}{{{\text{speed}}}}$ to determine after how many hours these cars will meet each other.complete step-by-step answer:given, distance between the two cars d=160 kmstarting time for both the cars when they left their respective initial positions a and b is 8:10 amspeed of the first car, x=50 km per hourspeed of the second car, y=30 km per hourin order to obtain the relative speed between these two cars which are moving towards each other (i.e., in opposite directions), the individual speeds of these cars will be added.so, the relative speed between the two given cars, r= x+y=50+30=80 km per houras we know that, time taken$ = \dfrac{{{\text{distance travelled}}}}{{{\text{speed}}}}$so, time when both the cars will meet=$\dfrac{{{\text{initial distance between both the cars}}}}{{{\text{relative speed between the cars}}}} = \dfrac{{\text{d}}}{{\text{r}}} = \dfrac{{160}}{{80}} = 2$ hours.after 8:10 am, both the cars which are initially at different places a and b will meet each other in the next 2 hours.therefore, time when they will meet each = 8:10 am + 2 hours = 10:10 amhence, option a is correct.note: in this particular problem, since the given two cars are moving in opposite directions (or moving towards each other) that’s why the individual speed of the cars are added in order to determine the relative speed between them but if they were moving in the same direction then the relative speed between these cars would have been obtained by subtracting the individual speed of these cars. we first define our axisupward is along + y direction of axiseastward is along + x direction of axisvelocity of a aeroplane = velocity of a bullet = a person on the earth will see the bullet having a resultant velocity and angle θ with the vertical (y axis)θ = angle with the vertical (y axis) How you do this will depend on a number of factors: since you haven't tried to explain in any detail, I'll assume you know nothing, and just give you the basics.  

  

The easiest way to do this is to read the text file into a single string, and then use the .NET framework to find the match:  


```
Dim text As String = File.ReadAllText("D:\Temp\MyFile.txt")
Dim index As Integer = text.IndexOf("hello")
If index >= 0 Then
   ' String is in file, starting at character "index"
End If
```
  

There are other ways, but that is pretty much the simplest. (a) to my eye, they never have a common speed. that would require the two curves to have the same slope at the same time, which doesn't appear to me to be true.

(b) b is ahead of a but is slowing down and being passed by a, which has been moving at constant speed.

(c) b has an acceleration with greater magnitude. (in fact, the curve for a doesn't show any acceleration at all.)

(d) a has a constant slope, and therefore a constant velocity (and therefore displays no acceleration at all). b starts ahead of a initially with a velocity greater, but then decelerates as it nears t = 4 s. at around t = 3.7 s, b's velocity (slope) has nearly dropped to zero, and it gets passed by a.

if you find this helpful, please select favorite answer! After 5 hours of learning I have compiled these:


Mindset



1. **Make sure the placed image ratio is good** to make it more realistic. This can be attained by checking with the other object in the output picture, like trees, or other peoples' height. You are not going to place human with the size much smaller than the other human at the same picture. Similarly, you also must not place a person with the height higher than a tree.
2. **Get the right perspective**. Sometimes, when an object is placed in an odd perspective, image is going to look very bold that it has been photoshopped or copy pasted.
3. **Lighting**. It is important to pay attention to light source, like the sun, and make sure our object is appropriate with output background light source. This can be done by adjusting the lighting of object and adding shadow with referencing other shadow in output image.


Tools (to make edges more realistic)



1. **Layer masking.** If moving people, hair can look awful if just plainly moved. Masking allows us to further tweak our selection.
2. **Refine edge.** *This tool allows you to control many aspect of the edge of your selection* (desired object to move), like Edge Detection (brushing the edges of object and let photoshop do its job, usually around dog fur), Feather (Soften the area of selection), Smooth (reduce pointiness of your selection), Contrast (somewhat opposite of smooth), and Shift Edge (moving feather far or nearer the selection, usually to remove excess background color near the edges). *REFERENCE: <https://www.youtube.com/watch?v=5lDr2Nd8Yl4>*
3. **Layer Matting**. Inside we have many sub-tools to work on, like Color Decontamination (spread out soft mask around the edge, usually for hair to catch other hair that accidentally masked or can be used similarly to Shift Edge), Remove Matte (soften edge of sharp graphic or pixalated, raster look). *REFERENCE: <https://www.youtube.com/watch?v=N6K_htNQPPA>*
4. **Image Calculation**. By playing with the blending, we can make the background darker; thus, helping us making mask. *REFERENCE: <https://www.youtube.com/watch?v=0zf-H9RoCNk>* biomarker = "hi!"

def cells = getdetectionobjects()

cells.each{

it.setname(biomarker)

}

all of the cells will now be named hi! You can use SetCursorPos() to control the position of the cursor. It returns true is it succeeds and false if not. It takes 2 arguments int x and int y. You can use GetCursorPos() to retrieve the position of cursor. it returns the same as Set...() it takes one paramater a pointer to a structure of type POINT, which contains to values long x and long y. Also if you want to send Mouse clicks then you will need to look into the function SendInput() its well documented on msdn but feel free to ask for more information.



Chris hi [@cavediver](/u/cavediver), welcome to the forum :slight\_smile:

[image] cavediver:

could the ping sonar be used to deduce a forward velocity (perhaps with a doppler shift calculation)?

both the [ping sonar altimeter and echosounder](https://bluerobotics.com/store/sensors-sonars-cameras/sonar/ping-sonar-r2-rp/), or the [ping360 scanning imaging sonar](https://bluerobotics.com/store/sensors-sonars-cameras/sonar/ping360-sonar-r1-rp/) are designed and set up to work as …