openmv_ros

Due to the chnage of idea management-wise at the time and the lack of hardware available to me, this is unmaintained. Refer to the fallback solution ;)

Fallback solution

You can do the communication using the serial CDC driver of the OpenMV board.

On the OpenMV camera:

import sensor, image, time, math, pyb

usb_vcp = pyb.USB_VCP()
usb_vcp.setinterrupt(-1)

sensor.reset()
sensor.set_pixformat(sensor.GRAYSCALE)
sensor.set_framesize(sensor.VGA)
sensor.set_windowing((640, 60))
sensor.skip_frames(time = 125)
sensor.set_auto_gain(False, value=10)
sensor.set_auto_whitebal(False)
sensor.set_auto_exposure(False, value=125)
sensor.set_colorbar(False)

while True:
    clock.tick()
    img = sensor.snapshot()
    codes = img.find_barcodes()

    for code in codes:
        text = "".join([code.payload(), "\t", str(code.quality()), "\n"])
        usb_vcp.send(text, timeout=usb_timeout)

    if len(codes) == 0:
        usb_vcp.send("\n", timeout=usb_timeout)

Then you read the data from the computer:

    def spinonce(self):
        """Spin to read."""
        lines = []
        received = False

        while self.serial.in_waiting:
            line = self.serial.readline()
            lines.append(line)
            received = True

        codes = []
        if received:
            for line in lines:
                code = self.parseline(line)
                if code is not None:
                    codes.append(code)

            self.msg.header.stamp = (rospy.Time.now() - self.delay)
            self.msg.barcodes = codes
            self.barcode_to_world(self.msg)
            self.topic.publish(self.msg)

How it should look like is below

ROS driver to OpenMV camera, implementing the ROSSerial protocol. Working on the OpenMV7.

Generate Messages

Not done yet, generate the standard ROS message then follow the message structure as shown in openmv_ros/message_example. This should not be hard to create the generator.

Main differences from the ROS message:

Python3
Use a wrapper arround ustruct (microPython struct).
Less dependencies
No numpy support
Has a __str__ method as it does not extend the genpy message class, can be solved.

Install

Put all the messages inside your device plus microros.py, then make your main.py program.

Run

Will be starting the standard ROSSerial node like:

roslaunch rosserial_server serial.launch baud:=115200 port:=/dev/ttyACM0

Contributing

Branch, send a PR, thanks!

Status

WIP: * Making the rospy interface, Publishers and Subscribers + default messages I need (TopicInfo, Tag, Tags, ROI)

Later work: * ROS message generation * Service implementation * Make the generic message to inherit from

Credits

Alexis Paques (@AlexisTM)

AlexisTM/openmv_ros