What is the USB Camera handler
TQLEngine provides a protocol handler wrapper to interact with USB Camera. USB Camera are handy actuators for home monitoring, taking one off pictures etc.
- High frame rate MJPEG 60 fps @ 1280 (H) x 720 (V) , 30 fps @ 1920 (H) x 1080 (V)
- CMOS 1080P sensor for high quality image and low power consumption
- high pixel technology for sharp image and accurate color reproduction
- low light performance - ideal for any lighting condition
- UVC for use in Linux, Windows XP, WIN CE, MAC, SP2 or above
USB Camera Parameters
| Parameter Name | Description |
|---|---|
USBCameraParameters.ImageFormat | Specify image format. Example: jpeg |
USBCameraParameters.SaveToDisk | Do you want the image file to be saved to disk?. Value is either true or false |
USBCameraParameters.ImageName | Specify the file name to be used when saving to the disk. The file gets saved in the current folder in which TQLEngine is running |
USBCameraParameters.Size.Height | Image height. An integer value |
USBCameraParameters.Size.Width | Image width. An integer value. |
...
| USBCameraParameters.Configuration.Standard | Standard value of image |
| USBCameraParameters.Configuration.Quality | Quality of image |
| USBCameraParameters.Configuration.Channel | The acquisition channel. Default is 0 |
| USBCameraParameters.Configuration.Brightness | Brightness of video image (0-255) |
| USBCameraParameters.Configuration.Contrast | Contrast of image (0-255). |
| USBCameraParameters.Configuration.Gamma | Gamma of image |
| USBCameraParameters.Configuration.Gain | Gain of image |
| USBCameraParameters.Configuration.Sharpness | Sharpness of image (0-255). |
| USBCameraParameters.Configuration.Saturation | Saturation of image (0-255). |
| USBCameraParameters.Configuration.Hue | Hue of image |
USB Camera Parameter Structure
| Code Block | ||||||
|---|---|---|---|---|---|---|
| ||||||
<USBCameraParameters>
<ImageFormat></ImageFormat>
<SaveToDisk></SaveToDisk>
<ImageName></ImageName>
<Size>
<Height></Height>
<Width></Width>
</Size>
<Configuration>
<Standard></Standard>
<Quality></Quality>
<Channel></Channel>
<Brightness></Brightness>
<Contrast></Contrast>
<Gamma></Gamma>
<Gain></Gain>
<Sharpness></Sharpness>
<Saturation></Saturation>
<Hue></Hue>
</Configuration>
</USBCameraParameters> |
Invoking UCAM Handler
| Code Block | ||||||
|---|---|---|---|---|---|---|
| ||||||
<Action Name="USBCameraImageAction">
<Workflow Limit="1" Live="1" Timeout="-1">
<Task name="Main" while="true">
<Event name="Argument" as="ActionArgument"/>
<Invoke name="GetImage" waitFor="ActionArgument" post="ucam://">
<Message>
<Value>
<USBCameraParameters>
<ImageFormat>[%:Event.Argument.USBCameraParameters.ImageFormat.Value:%]</ImageFormat>
<SaveToDisk>[%:Event.Argument.USBCameraParameters.SaveToDisk.Value:%]</SaveToDisk>
<ImageName>[%:Event.Argument.USBCameraParameters.ImageName.Value:%]</ImageName>
<Size>
<Height>[%:Event.Argument.USBCameraParameters.Size.Height.Value:%]</Height>
<Width>[%:Event.Argument.USBCameraParameters.Size.Width.Value:%]</Width>
</Size>
<Configuration>
<Standard>[%:Event.Argument.USBCameraParameters.Configuration.Standard.Value:%]</Standard>
<Quality>[%:Event.Argument.USBCameraParameters.Configuration.Quality.Value:%]</Quality>
<Channel>[%:Event.Argument.USBCameraParameters.Configuration.Channel.Value:%]</Channel>
<Brightness>[%:Event.Argument.USBCameraParameters.Configuration.Brightness.Value:%]</Brightness>
<Contrast>[%:Event.Argument.USBCameraParameters.Configuration.Contrast.Value:%]</Contrast>
<Gamma>[%:Event.Argument.USBCameraParameters.Configuration.Gamma.Value:%]</Gamma>
<Gain>[%:Event.Argument.USBCameraParameters.Configuration.Gain.Value:%]</Gain>
<Sharpness>[%:Event.Argument.USBCameraParameters.Configuration.Sharpness.Value:%]</Sharpness>
<Saturation>[%:Event.Argument.USBCameraParameters.Configuration.Saturation.Value:%]</Saturation>
<Hue>[%:Event.Argument.USBCameraParameters.Configuration.Hue.Value:%]</Hue>
</Configuration>
</USBCameraParameters>
</Value>
</Message>
</Invoke>
<Log Message="******Invoked USBCamera******"/>
<Output name="Result" as="ActionResult">
<Value>
<Image>[%:[%:@Output:%]Invoke.GetImage.Message.Value:%]</Image>
</Value>
</Output>
</Task>
</Workflow>
</Action> |
Driver Installation Steps
For the ucam handler to work two things are needed, the video driver of the camera which comes by default and some prerequisite libraries which are shown below.
- libjpeg8-dev
- libv4l-dev
If you are running debian based operating system use the following commands
sudo apt-get install libjpeg8-dev
sudo apt-get install libv4l-dev
Refer to TQL CLI Protocol Install section for installation of USB Camera driver.