Possibile project

• dear all, we have a possibile project where in a sort of textile fabric wire are visible, annex here you have an example where in thsi fabric you can see 2 black wires in a sort of sine wave.

Targhet of this application is to measure

Horizontal distance between these 2 wires

Frequency of one of the 2 wire (sine frequency), acquisition is coming from linescan camera and for this we have a line frequency

Phase shift between these 2 sin wave.

the idea is to output distance and Frequency with 2 variable i can read from SDK

rappresent the phase shift with 8 bit using the 8 digital output of a Microenable IV GigE

i just need an idea of fesibility of this, for me measure phase shift and frequency is quite complex and i have no idea at all...

regards

pier

• Hi Pier

1. Find x-positions of fabric wires: Use a suitable algorithm like center of gravity, edge detection, slope, etc. The requirement is similar to a laser line detection. You could adapt the CoG algorithm from the SiSo example.

2. Get the frequency of the lines: The important question would be over which time the measurement should take place? The FFT operators are not available for mE4VQ4-GE, however the min-positions could be used to get the period time of exactly the last period. Besides that many more options exist. The selection depends on the requirement.

3. To detect the phase shift again the question would be: Use a specific area for the measurement or is the phase shift just the distance between two wires?

4. IO Output: I don't clearly understand you IO output format but this should not be the most difficult part of your application.

Johannes

 Johannes Trein Group Leader R&D frame grabberBasler AG

• Dear Johannes,

many thanks, agree with your observation and let me talk with customer

regarding the output on a digital IO let us suppose I have to represent a phase shift that can vary from 0 to 180°

I can represent this variation with 7 bit digital IO and use the latest output to trigger the read from customer

Basically 0° will be represented as binary 0000000 on first 7 Digital out, 180° will be represented as 1111111

I’ll have a resolution of 180° over 127 possible digital output values

The last Digital OUT (OUT8) will be set to 1 in order to “say” customer now is time to read digital output 1 to 7

Do not know if this clarify or confuse you….

Regards

Pier

• Dear Johannes,

I have now more details from customer, the frequency of wire waves is not as shown in image

I send you but is much more higher.

The distance between 2 pick of one wire is less than 50 acquired lines and the frequency can

be read as distance between 2 consecutive pick.

The same for the phase shift where the distance between the 2 pick on the 2 wires is needed.

Probably acquiring a single line or a few lines and detecting horizontal position is the first step for this.

but what is scaring me is the possible noise inside the image as example in image I send you

at coordinate 41, 1082 there is a spot this spot is very close to wire dimension if I only

consider a few lines acquired..

Any suggestion ?

What do you think about feasibility of this project?

Best regards

Pier

Files

• noise.PNG

• dear all, i have no feedback on my altest observation

can you let me know?

regards

pier

• Hi Pier

I think it is not very likely that your question will be answered from someone outside of Silicon Software as it is quite complex. The Silicon Software members can support solving design issues or give you some ideas within the forum. So if you upload some VA design with edge detection we can provide some ideas. For getting a solution to your application please contact your sales representative.