JPS58196412A - Distance measuring device - Google Patents

Abstract

PURPOSE:To make the processing time of a signal fast, by obtaining the sum or average value of image signals of segments at every column of a two dimensional image sensor, making the result to be the image signal of each column, thereby handling it as an equal signal to a linear image signal. CONSTITUTION:In an image sensor 10, a column scanning pulse input 11 and a row scanning pulse input 12 are inputted, and an image signal is outputted from the sensor. The signal passes an analog switch 14 and it is integrated in an integrator 15. The switching of the analog switch 14 is controlled by a column scanning pulse signal through a monostable multivibrator 16. The integrated value is transferred through an analog switch 17. The switch 17 is driven by row scanning pulses through a monostable multivibrator 18. Since the average value of the signals of the columns is outputted, the images in right and left optical systems are compared as in a linear sensor, and the distance is obtained. Since a target can be observed with a width being provided, a large error can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a distance measuring device using a triangulation method using an image sensor.

A conventional rangefinder based on the triangulation method has two optical systems, left and right, as shown in Fig. It is composed of an array 5 of photodetecting elements as a sensor. Then, the image of the target 6 obtained by the left optical system and the image obtained by the right optical system are detected by the photodetecting element array 5, and the reflecting mirror 3 is rotated so that the two images coincide, and the distance is determined from the rotation angle. I'm looking for.

However, in such a configuration, when used in an environment with a lot of vibration such as a car, errors may occur.
Alternatively, it has the problem of causing changes over time.

To solve this problem, as shown in FIG. A method is used to calculate the distance. If you hang it like this, there will be no moving parts, so it won't be affected by vibrations.

However, in terms of the degree of image recognition, using a two-dimensional image sensor provides more information, and it is possible to determine not only the distance but also the identity of the object. It is also possible to track specific patterns. but,
Since the amount of information is large, the time required for signal processing increases significantly. In particular, when measuring inter-vehicle distance as a stand-alone device, a fast response is required. For example, a car traveling at 100 b/h travels approximately 3 ofrL per second, so that calculations once take 1 to 2 seconds to become useless.

It is required that the calculation be completed in at least about 0.1 seconds. The microcomputers currently used in automobiles and home appliances are slow (it takes several seconds to process a two-dimensional image and calculate the distance. Therefore, as an image sensor , there is a tendency for one-dimensional linear image sensors to be used.1
A dimensional image sensor has a very narrow field of view in order to see the line that constitutes the target (especially if you want the left and right optical systems to look at the same line, it is extremely difficult to adjust the optical system. It has its drawbacks.

The present invention relates to a distance measuring instrument that eliminates the above-mentioned drawbacks and also shortens signal processing time. A detailed explanation will be given below with reference to the drawings.

FIG. 3 is a circuit diagram showing an embodiment of a distance measuring device according to the present invention. First, in order to widen the field of view, it is necessary to capture an image with a two-dimensional image sensor and average all the column signals. The signal from the two-dimensional image sensor scans the first column, and then sequentially scans the second and third columns. FIG. 4 shows the timing chart Y. For example, in the case of an image sensor with N rows and M columns, when pulses for scanning the columns are continuously output, a pulse for scanning the rows is generated every M pulses. This pulse outputs the image signal of each JII segment.

In the present invention, the image signal of each column is integrated for each row pulse to obtain a column signal. A detailed explanation will be given below using a specific circuit shown in FIG.

In FIG. 3, pulse voltages are input to the image sensor 10 from a column scanning pulse input 11 and a row scanning pulse input 12, and an image signal 7j is output accordingly. The image signal passes through an analog switch 14 and is integrated in an integration circuit 15. The analog switch 14 converts the column scanning pulse signal into a monostable multivibrator 16ya1.
Switching is controlled by pulses generated through the Also, the integrated value is passed through the analog switch IVY to the next I
Sent for 2 hours. Then, the switch 17 is driven by a pulse generated by the monostable multivibrator 18 from the row scanning pulse, and when the transfer is completed, the charge accumulated in the capacitor of the integration circuit is discharged, and the integration operation for the next image signal is started. .

In this way, since the average value of the signals in each column is output, the distance can be determined by comparing the images in the left and right optical systems, similar to the near sensor. In this case, the processing time includes the time to integrate the image signal of each row and the time to process the output of the linear image sensor by treating it as a signal, but the integration time is sufficient compared to the signal processing. Since it is short, it is considered to be equivalent to the signal processing time in a linear image sensor.

As explained above, according to the present invention, since it is possible to manually view a target with a certain width, alignment is relatively easy, and the image can be captured as an average of the overall image. Accordingly, large errors can be prevented. As described above, the distance meter according to the present invention has no moving parts (and can process signals at high speed, so the error rate is low, making it suitable for single-mounted inter-vehicle distance measurement). 0 with excellent effects

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a rangefinder using the triangulation method, Fig. 2 is a schematic diagram of a rangefinder using a linear image sensor, and Fig. 3 is a circuit diagram showing an embodiment of the rangefinder according to the present invention. 4
Figures (a) to (C) are waveform diagrams of various parts in Figure 3. lO... Image sensor, 11... Column scanning pulse input, 12... Row scanning pulse input, 13... Image output, 14... Analog switch, 15°°/integrating circuit, 16... Multivibrator, 17...Analog switch, 18°° Monostable multivibrator.

Claims (1)

[Claims] Comprising essentially two optical systems combining a two-dimensional image sensor and a lens, which are divided into two dimensions of rows and columns and having segments, - measuring the distance by the principle of triangulation by comparing the respective images; In distance measuring instruments,
By calculating the sum or average value of the segment image signals for each column and using it as the image signal for each column, it can be treated in the same way as a linear image signal and signal processing can be simplified.
Distance measuring device featuring 4F.