machine vision to control the cut position
David from Canada  [2 posts]
6 years
We are the large format digital print company.
I have a used fotoba cutter was made in Italy, it can work for us due to the sensor is design for the photo paper when I contact their support and try to ask them to sell me the new sensor, they refuse to do it and ask me to buy the new machine, but I did spend $5000 for the used one already, from the design point for of view this is a good machine,
the feed rate is up to 10ft/min, but I can slow it down to 3ft/min too.
Programmable double cut
Optical automatic alignment

I plan to modify the machine,
I want to use your software to detect the edge of the poster, check the alignment, if it is wrong, I want to use your software and send the signal to the arduino and control the motor to adjust the cut angle. the the paper advance motor will move the paper to the cut position to cut one before and after the mark.
the mark print is generated by the RIP software, I need some way from your sensor to detect this and let me program the cut position, normally it need to cut before and after the bar, when it see the second bar, it will also do the cut before and after too.

the normal print size of the poster is about 22x28", but you know it can be any size, depend on the customer need.

on the other hand, do you think you software is so smart to the point it can recognize the poster crop mark and do the cut without this double bar, my RIP software can generate the crop mark like the cross or a L on the corners of the print. I can program it any size I want. if this is the case this design will be a lot more powerful, since most RIP software can generate the crop mark but not many can do the fotoba mark (the 2 double lines).

what camera should I buy to do this with your software, and is their any example on how I can do the program.

the old machine has 2 sensors, it is using this to check the align of the paper, in case there is the angle, it will adjust the blade and make the cut parallel to the print.
I need to do this part too. Let me know if all this work is possible to use your software.
Thanks for all you support.

Anonymous 6 years

Yes, this is possible to do. In fact if you want you can send an image with the ideal crop marks as those should be possible to detect aswell. Either way your first step would be to attach a camera at the position where the crop mark would best be visible and then see what that looks like. You should start with any webcam you have around and then based on the results we would know more about how to change the webcam in order to get better results.

If you have a couple examples of other crop marks that your application can generate those may be useful to know. Naturally the longer the mark the better the angle would be determined.

The hard part is not the marker reading and interpretation but the knowledge of what to do with that information once determined. Do you know how to interface an Arduino with the cutter? Is this something that is documented? If not, knowing the crop marks would not be very helpful if you cannot control the cutter in a custom manner. That would be an area that I would first check that this is possible.

David from Canada  [2 posts] 6 years
Here is the photos of the mark that I have to read.
I did do some basic test to use the arduino motor shild to drive the cutter motor, the cut alignment motor and the paper advance motor, they are all ok, but so far I have no way to use the old sensor to send a signal to trigger the motor.
From your software, please check if you can read this and what is the respond time to send out the signal, the paper advance can be adjust from 1 - 10 ft / min. How to connect your software to arduino?

btw the mark is all the way across the image on the top, my paper are usually 50" or 36" wide.
since my plan to use only the structure and the motors only, therefore it is up to us to control the software now.
one idea I can think of is to take the image 12" before the cutter, this case we have some time to adjust the stop and adjust the blade and trigger the cut, is this make sense.

Anonymous 6 years

See attached and try the test.jpg image (your original one above). Seems to run around 0.1 seconds or 100 milliseconds. Need to test on MANY more sample images.

See Sparkfun_Arduino module or MCU_Module for connection to the Arduino. Or if you want to roll your own see the Serial module.



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