This time, we would like to talk about the trigger mode of the camera and the usage suitable for each mode.
Once you know the trigger mode, you will be able to build an inspection system that suits your needs.
Trigger is written in English as “Trigger” and means “trigger” that determines when the camera captures an image.
The following are three types of trigger modes.
１）No trigger
Suddenly it seems that “no trigger” is the trigger mode, but we wrote it because Easy Inspector is most often used in this state.
“No trigger” means that the image is always captured as a video from the camera, and when an inspection start command is received with a button or communication command, one frame of the image captured as a “currently” video is taken out and image processing is performed.
Advantages
- It is compatible with many cameras including webcams. Therefore, the inspection system can be configured at the lowest cost.
Disadvantages
- Since images are always captured as video, the CPU load is heavy and the number of cameras that can be connected is limited (generally about 2 or 3).
- There is a time lag (0.2 seconds for 0.3 Megapixel, 1 second for 3.0 Megapixel) until the image taken by the camera is actually imported to the PC as a movie.
Therefore, if you place the inspection item and start the inspection immediately, your hand may be taken due to a time lag.
Usage
- Items that can be inspected while stopped.
- A relatively slow inspection that can be inspected after waiting a second or two after placing the inspection product.
２）Soft trigger
At the start of the inspection, the software sends a command to the camera to “take one image and send it”, and only one image is acquired and subjected to image processing.
Advantages
- Compared to the method of capturing video, the load on the CPU is smaller and more cameras can be connected.
- There is no need to worry about time lag because only one image is captured when the inspection start command is given.
Disadvantages
- Compared to the “hard trigger” explained below, there is a slight blur in the shooting timing. Therefore, it may not be suitable for inspecting objects moving on the conveyor.
- There are few cameras that support it (please contact us for the model).
- The price of the camera is high.
Usage
- Inspection that requires a large number of cameras.
- When you want to shoot immediately after placing an object.
- Inspection while timing with external devices such as PLC and applications.
３）Hard trigger
The signal that triggers image capture is transmitted directly to the camera.
The soft trigger is “the camera shoots by the command of the software”, while the hard trigger is the operation of “shooting without the command of the software by the signal directly entering the camera”.
In the human analogy, the soft trigger is the action of kicking the ball with a command from the brain, and the hard trigger is the action of raising the foot reflexively when the knee is hit like a beriberi test.
At this time, the camera shoots without any command from the software, so the operation is to send the image taken without permission to the software side. The software processes the sent image and makes a pass / fail judgment.
Advantages
- Since the image capture signal goes directly to the camera, it can be timed very precisely (for example, shooting starts 0.0001 seconds after the signal is input).
Therefore, even moving objects on the conveyor can be reliably captured and photographed by the photoelectric sensor.
Disadvantages
- It is necessary to install a sensor to input a signal to the camera, make a circuit, and wire it.
(SNiPER2 uses a hard trigger, but it integrates peripheral circuits that require electrical knowledge so that it can be used only by installing a sensor.) - There are few cameras that support it (please contact us for the model).
- The price of the camera is high.
Usage
- Inspection of moving objects on the conveyor.
- Inspection frequency is less than 1 second.
If you contact us, we will propose a configuration that suits your needs.
