JP2940028B2 - Vision sensor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a visual sensor for capturing an image of an object and recognizing the shape and position of the object.

<Prior Art> Conventionally, in the field of factory automation, a visual sensor to which image processing technology is applied has been introduced in order to determine the quality of a product. The visual sensor captures an image of a product flowing on a manufacturing line, captures the image, and extracts a characteristic amount such as an area or a perimeter to determine whether or not the shape of the product is appropriate. In this case, since the number of products per unit time flowing through the production line is limited, grasping the time required for measuring the characteristic amount (hereinafter referred to as “measurement time”) is effective in increasing the efficiency of the production line. is necessary.

<Problems to be Solved by the Invention> However, with the conventional visual sensor, it is impossible for an operator to accurately grasp the measurement time of the feature quantity, and the measurement time is determined by the type of the feature quantity to be measured and the number of items. Is very different, so it is not easy to estimate the measurement time.
It has been difficult to improve the efficiency of the production line.

The present invention has been made in view of the above-described problem, and a visual sensor that enables a worker to always accurately grasp the measurement time of the feature value by displaying the measurement result by measuring the measurement time of the feature value and displaying the measurement result. The purpose is to provide.

<Means for Solving the Problems> In order to achieve the above object, in the visual sensor of the present invention, an imaging unit for imaging an object to generate an input image;
A feature amount measuring unit that measures a feature amount of an input image and outputs measurement data and outputs signals corresponding to the start and end of the measurement, and a feature amount measurement based on a signal input from the feature amount measuring unit. A timing means for measuring the time required;
Display means for displaying the measurement result by the time keeping means.

<Operation> The measurement time of the feature amount is measured for the input image and the measurement result is displayed. Therefore, even if the type of the feature amount to be measured or the number of items is changed, the operator can see the display and adjust the measurement time of the feature amount. It is always possible to grasp accurately and it is possible to improve the efficiency of the production line.

FIG. 1 shows the appearance of a visual sensor according to an embodiment of the present invention, and includes a camera 1, a controller 2, a video monitor 3, and the like.

The camera 1 captures an image of the object 4 and generates a grayscale image.
After the grayscale image is taken into the controller 2 and binarized, the feature amount such as the area and the perimeter of the binary image is measured. The measurement data is output to a programmable controller (not shown) or the like to control a production line in factory automation.

In the controller 2, the measurement time of the feature amount is measured, and the measurement result is output to the video monitor 3.

The video monitor 3 displays a grayscale image and a binary image of the object, and also displays a measurement result by the controller 2, and FIG. 2 shows a display example of a monitor screen.

In the figure, 5 is an image display area for displaying a grayscale image or a binary image, 6 is a data display area for displaying a measurement result, and a data display area 6 is provided for each measurement time. The measured value and the average, maximum, and minimum values of the measurement time are displayed.

Further, in this embodiment, the time required to output the measurement data of the characteristic amount (hereinafter, referred to as “data output time”) is also measured by the controller 2, and the measured value of the data output time and the average value thereof are measured each time. , Maximum value, and minimum value are also displayed in the data display area 6.

FIG. 3 shows a circuit configuration example of the controller 2.

In the figure, an A / D converter 7 converts a grayscale image video signal into a digital signal, and a binarization processor 8 binarizes the digital signal with a predetermined threshold to generate a binary image. I do.

The measuring unit 9 includes an image memory for storing the binary image, measures a characteristic amount such as an area of a black pixel portion and a peripheral length of the binary image, and writes the measured data to a data buffer (not shown). Then, output to the programmable controller. The measurement unit 9 outputs a measurement start signal at the time of starting the measurement of the characteristic amount, a measurement end signal at the end of the measurement of the characteristic amount, and a write end signal at the end of the writing to the measurement data buffer.

The CPU 10 measures the measurement time and the data processing time based on the measurement start signal, the measurement end signal, and the write end signal with respect to the characteristic amount measurement processing by the measurement unit 9, and also calculates the average value of each measurement value, Calculate the maximum and minimum values. In the case of this embodiment, the clocking process is performed by a software timer. However, the present invention is not limited to this.

FIG. 4 shows a procedure for measuring the measurement time by the CPU 10.

When the binary image is captured by the measuring unit 9 and the measurement of the feature is started, the measuring unit 9 outputs a measurement start signal to the CPU 10. As a result, the determination in step 1 (shown as “ST1” in the figure) of the figure becomes “YES”, and the CPU 10 starts the internal timer counter and starts the clock counting operation (step 2). The generation period of this clock is, for example, 10 ms
Every time the unit time elapses, the determination in step 3 becomes "YES" and the timer counter counts up (step 4).

When the measurement unit 9 completes the measurement of the determined feature amount, the measurement unit 9 outputs a measurement completion signal to the CPU 10. As a result, the determination in step 5 becomes “YES”, the CPU 10 stops the timer counter, stops the counting operation of the clock, and then outputs the contents of the timer counter as a measured value of the measured time (steps 6 and 7). ).

Although the figure shows only the measurement time measurement procedure, the data output time measurement procedure is the same, and the timer counter measures the time from the measurement end signal generation time to the write signal generation time. Will be counted.

FIG. 5 shows a procedure for calculating the average value, the maximum value, and the minimum value of the measurement time by the CPU 10.

After the CPU 10 clears the internal counter N in step 1 of the figure, the CPU 10 measures the measurement time in step 2 and acquires the measurement value T of the measurement time in step 3. Next, after incrementing the counter N, the CPU 10 displays the measured value of the measurement time on the data display area 6 of the video monitor 3 (steps 4 and 5).

In the next step 6, it is determined whether or not the content of the counter N is 1. In this case, since the determination is "YES", the CPU 10 stores the measured value T in the internal storage area MAZ, MIN, SUM.
Set each. Among these data storage units, MAX
Is the maximum value storage unit for storing the maximum value of the measured value, MIN
Is the minimum value storage unit for storing the minimum value of the measured value, SUM
Is a total value storage unit for storing the total value of the measured values.

Next, when the second measurement time is measured and the next measurement value T is obtained (steps 2 and 3), the CPU 10 increments the counter N and then transmits the measurement value T of the measurement time to the video monitor 3. It is displayed (steps 4 and 5).

At this stage, since the content of the counter N is 2, the determination in the next step 6 is “NO”, and the CPU 10 determines in step 8 whether the current measured value T is larger than the content of the maximum value storage MAX. Is determined. If the judgment in step 8 is "YE
If "S", the process proceeds to step 9 where the contents of the maximum value storage unit MAX are replaced with the current measured value T.

If step 8 is “NO”, then the CPU 10 determines in step 10 whether the current measured value T is smaller than the contents of the minimum value storage unit MIN. If the judgment in step 10 is “YE
If "S", the process proceeds to step 11, and the content of the minimum value storage unit MIN is replaced with the current measured value.

Next, the CPU 10 adds the current measurement value T to the contents of the total value storage unit SUM, divides the added value by the current value of the counter N to obtain an average value, and calculates the average value in the average value storage unit inside the CPU 10. Stored in H (steps 12 and 13). Next Step 14
After displaying the contents of the average value storage unit H, the maximum value storage unit MAX, and the minimum value storage unit MIN in the data display area 6 of the video monitor 3, the CPU 10 continues the measurement in step 15. And then perform the same procedure.

Although the figure shows the calculation process for the measurement time, the calculation process for the data output time is also the same,
Here, illustration and description thereof are omitted.

<Effect of the Invention> As described above, the present invention measures the measurement time of the characteristic amount for the input image and displays the measurement result. Therefore, the operator always accurately grasps the measurement time of the characteristic amount by looking at this display. As a result, it is possible to improve the efficiency of the production line, thereby achieving a remarkable effect of attaining the object of the invention.

[Brief description of the drawings]

FIG. 1 is an external view of a visual sensor according to an embodiment of the present invention, FIG. 2 is an explanatory diagram showing an example of a monitor screen, FIG. 3 is a block diagram showing an example of a circuit configuration of a controller, and FIG.
Flow chart showing the measurement time measurement procedure by the CPU,
FIG. 5 is a flowchart showing a processing procedure of the measurement time by the CPU. 1 ... camera 2 ... controller 3 ... video monitor 9 ... measuring unit 10 ... CPU

Claims (1)

(57) [Claims] 1. A visual sensor for imaging an object and recognizing its shape, position, and the like, an imaging means for imaging the object to generate an input image, and measuring and measuring a feature amount of the input image. A feature quantity measuring means for outputting data and a signal corresponding to the start and end of the measurement; a time measuring means for measuring a time required for measuring the feature quantity based on a signal input from the feature quantity measuring means; Display means for displaying a measurement result by the means.