TechNexion USB Camera User Guide

Introduction

This article guides you how to get started using TechNexion USB camera on Windows and Linux.

Supported Camera Modules

How to use

There are several methods to use the camera when you connect it to a computer or embedded development kit via a USB cable.

Method 1 - Using TechNexion VizionViewer (Windows/Linux)

VizionViewer™

Method 2 - Using V4L2 Control (Linux)

1. List all devices.

$ v4l2-ctl --list-device

VCI-AR0144-C (usb-xhci-hcd.1.auto-1.2):
        /dev/video0
        /dev/video1
        /dev/media0

2. List camera formats.

$ v4l2-ctl -d /dev/video0 --list-formats-ext
ioctl: VIDIOC_ENUM_FMT
        Type: Video Capture

        [0]: 'UYVY' (UYVY 4:2:2)
                Size: Discrete 1280x800
                        Interval: Discrete 0.017s (60.000 fps)
                        Interval: Discrete 0.033s (30.000 fps)
                Size: Discrete 1280x720
                        Interval: Discrete 0.017s (60.000 fps)
                        Interval: Discrete 0.033s (30.000 fps)
                Size: Discrete 640x480
                        Interval: Discrete 0.017s (60.000 fps)
                        Interval: Discrete 0.033s (30.000 fps)
        [1]: 'MJPG' (Motion-JPEG, compressed)
                Size: Discrete 1280x800
                        Interval: Discrete 0.017s (60.000 fps)
                        Interval: Discrete 0.033s (30.000 fps)
                Size: Discrete 1280x720
                        Interval: Discrete 0.017s (60.000 fps)
                        Interval: Discrete 0.033s (30.000 fps)
                Size: Discrete 640x480
                        Interval: Discrete 0.017s (60.000 fps)
                        Interval: Discrete 0.033s (30.000 fps)

3. List camera v4l2 controls.

$ v4l2-ctl -d /dev/video0 --list-ctrls

User Controls

                     brightness 0x00980900 (int)    : min=0 max=32 step=4 default=16 value=16
                       contrast 0x00980901 (int)    : min=0 max=10 step=1 default=5 value=5
                     saturation 0x00980902 (int)    : min=0 max=80 step=8 default=16 value=16
        white_balance_automatic 0x0098090c (bool)   : default=1 value=1
                          gamma 0x00980910 (int)    : min=0 max=40 step=1 default=18 value=18
                           gain 0x00980913 (int)    : min=1 max=48 step=1 default=1 value=1
           power_line_frequency 0x00980918 (menu)   : min=0 max=2 default=0 value=0 (Disabled)
      white_balance_temperature 0x0098091a (int)    : min=2300 max=15000 step=1 default=5000 value=5000 flags=inactive
                      sharpness 0x0098091b (int)    : min=0 max=64 step=8 default=32 value=32
         backlight_compensation 0x0098091c (int)    : min=0 max=480 step=8 default=256 value=256

Camera Controls

                  auto_exposure 0x009a0901 (menu)   : min=0 max=3 default=0 value=0 (Auto Mode)
         exposure_time_absolute 0x009a0902 (int)    : min=1 max=10000 step=1 default=330 value=100 flags=inactive
                   pan_absolute 0x009a0908 (int)    : min=-648000 max=648000 step=3600 default=0 value=0
                  tilt_absolute 0x009a0909 (int)    : min=-648000 max=648000 step=3600 default=0 value=0
                  zoom_absolute 0x009a090d (int)    : min=100 max=800 step=1 default=100 value=100

4. Camera streaming test with UYVY format.

$ v4l2-ctl -d /dev/video0 --set-fmt-video=pixelformat=UYVY,width=1280,height=800 --stream-mmap
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< 59.84 fps
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< 59.85 fps

Using "Ctrl+C" to exit v4l2 streaming.

5. Camera streaming test with MJPG format.

$ v4l2-ctl -d /dev/video0 --set-fmt-video=pixelformat=MJPG,width=1280,height=800 --stream-mmap
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< 59.84 fps
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< 59.85 fps

Using "Ctrl+C" to exit v4l2 streaming.

Method 3 - Using GStreamer (Linux)

1. List all devices and formats.

$ gst-device-monitor-1.0

Device found:

        name  : VCI-AR0144-C
        class : Video/Source
        caps  : video/x-raw, format=UYVY, width=1280, height=800, pixel-aspect-ratio=1/1, framerate={ (fraction)60/1, (fraction)30/1 }
                video/x-raw, format=UYVY, width=1280, height=720, pixel-aspect-ratio=1/1, framerate={ (fraction)60/1, (fraction)30/1 }
                video/x-raw, format=UYVY, width=640, height=480, pixel-aspect-ratio=1/1, framerate={ (fraction)60/1, (fraction)30/1 }
                image/jpeg, parsed=true, width=1280, height=800, pixel-aspect-ratio=1/1, framerate={ (fraction)60/1, (fraction)30/1 }
                image/jpeg, parsed=true, width=1280, height=720, pixel-aspect-ratio=1/1, framerate={ (fraction)60/1, (fraction)30/1 }
                image/jpeg, parsed=true, width=640, height=480, pixel-aspect-ratio=1/1, framerate={ (fraction)60/1, (fraction)30/1 }
        properties:
                udev-probed = true
                device.bus_path = platform-xhci-hcd.1.auto-usb-0:1.2:1.0
                sysfs.path = /sys/devices/platform/soc@0/32f10108.usb/38200000.usb/xhci-hcd.1.auto/usb2/2-1/2-1.2/2-1.2:1.0/video4linux/video0
                device.bus = usb
                device.subsystem = video4linux
                device.vendor.id = 3407
                device.vendor.name = TechNexion
                device.product.id = 0144
                device.product.name = VCI-AR0144-C
                device.serial = TechNexion_VCI-AR0144-C_000000008E604600A159178868A11A1A
                device.capabilities = :capture:
                device.api = v4l2
                device.path = /dev/video0
                v4l2.device.driver = uvcvideo
                v4l2.device.card = VCI-AR0144-C
                v4l2.device.bus_info = usb-xhci-hcd.1.auto-1.2
                v4l2.device.version = 393527 (0x00060137)
                v4l2.device.capabilities = 2225078273 (0x84a00001)
                v4l2.device.device_caps = 69206017 (0x04200001)
        gst-launch-1.0 v4l2src ! ...

2. Preview with UYVY format.

$ gst-launch-1.0 v4l2src device=/dev/video0 ! "video/x-raw, format=(string)UYVY, width=(int)1280, height=(int)800" ! videoconvert ! autovideosink sync=false

3. Preview with MJPG format.

$ gst-launch-1.0 v4l2src device=/dev/video0 ! "image/jpeg, width=(int)1280, height=(int)800" ! jpegdec ! autovideosink sync=false

GStreamer element

The element depends on your system, so the example may not be suitable for your system.

Troubleshooting

• Auto-suspend
  Since the camera's standby power consumption is low, the system may disconnect camera through the auto-suspend function as like below.

[86452.959044] usb 2-1.2: new SuperSpeed USB device number 5 using xhci-hcd
[86452.983505] usb 2-1.2: LPM exit latency is zeroed, disabling LPM.
[86453.022662] usb 2-1.2: Found UVC 1.10 device VCI-AR0144-C (3407:0144)
[86453.139540] input: VCI-AR0144-C as /devices/platform/soc@0/32f10108.usb/38200000.usb/xhci-hcd.1.auto/usb2/2-1/2-1.2/2-1.2:1.0/input/input8
[86467.470212] usb 2-1.2: USB disconnect, device number 5
[86468.959511] usb 2-1.2: new SuperSpeed USB device number 6 using xhci-hcd
[86468.983960] usb 2-1.2: LPM exit latency is zeroed, disabling LPM.
[86469.022673] usb 2-1.2: Found UVC 1.10 device VCI-AR0144-C (3407:0144)
[86469.139501] input: VCI-AR0144-C as /devices/platform/soc@0/32f10108.usb/38200000.usb/xhci-hcd.1.auto/usb2/2-1/2-1.2/2-1.2:1.0/input/input9
[86472.078213] usb 2-1.2: USB disconnect, device number 6

You can first check flag of auto-suspend and modify it to turn off this function.

$ cat /sys/module/usbcore/parameters/autosuspend
2

$ echo -1 > /sys/module/usbcore/parameters/autosuspend

After turning off auto-suspend, you need to reconnect the camera.

• Floating framerate
  Because of the product feature "Designed for Low Light Applications", the camera will increase exposure time via automatic exposure mode to maintain image quality in low-light environment.
  You can change the camera to manual exposure mode to keep the framerate. However, if you increase exposure gain in low-light environment, you will see more noise.

$ v4l2-ctl -d /dev/video0 --set-ctrl auto_exposure=1

The other way, you can use VizionViewer™ or VizionCTL to change to AGC mode (Auto gain control, Manual exposure time).