JP2554102B2 - Slit optical detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to the distance of surrounding articles such as eyes of a robot,
The present invention relates to a slit light type detection device that enables shape recognition at high speed.

(Prior Art) A conventional example of a distance measuring device using slit light will be described with reference to FIG. 3, in which slit light from a slit light source (b) connected to a light source power source (c) to a detection target (a) is slit light. And the image of the detection object (a) for slit light irradiation is picked up by the TV camera (1), and the image signal output from the TV camera (1) is digitized by the A / D converter (2). The arithmetic circuit (4) compares the image recorded in the first image memory (3a) and the image recorded in the image memory (3a) with a certain threshold value, and if the density value of the image is larger than the threshold value, "1" is given. , If it is smaller, it is binarized so as to be “0”, and the binary image is recorded in the second image memory (3b). At this time, the optical output of the slit light is selected so that the slit light is imaged clearly and brighter than the detection target (a) and the background, or only the wavelength light of the slit light is supplied to the lens of the television camera (1). If an interference filter that allows light to pass through is attached, the image memory (3b) produces an image of only slit light.

In order to calculate the distance of the detection object (a), it is necessary to obtain the position of the slit light image for each scanning line of the image recorded in the image memory (3b), and as shown in FIG. In order to reduce the position detection error due to the binarization threshold, it is necessary to find the center position of the slit light image. Therefore, in the arithmetic circuit (4), the start point and the end point of the slit light beam are obtained for each scanning line, The operation of obtaining the average is repeatedly performed, and the distance to the inspection object is calculated by determining the position of the slit light on each scanning line.

(Problems to be Solved by the Invention) In the conventional slit light type detection device, in order to obtain the center position of the slit light from the binary image recorded in the second image memory, data is fed from the image memory to an arithmetic circuit. The central position of the slit light is calculated by the arithmetic circuit and the processing time is long and the load of the arithmetic circuit is large.

(Means for Solving Problems) The present invention is a slit light type detection device developed in order to address the above problems, and is output from a television camera that images a detection target of slit light irradiation. An image signal for each horizontal synchronization signal, in the slit light detection device for calculating and detecting the distance and further the shape of the detection target in the arithmetic circuit, a binarization circuit that makes the image signal a binarization signal, Two signals are output, which are reset by the horizontal synchronizing signal and newly generate a synchronous first pulse signal corresponding to the horizontal resolution of the image signal, and a second pulse signal having a period twice that of the first pulse signal. The slit light image center position signal is obtained by counting the first pulse signal and the second pulse signal which are switched and output by the binarized signal for each of the horizontal synchronizing signals and which have a pulse generation circuit. A slit light image center position output circuit for inputting to the calculation circuit is provided,
A slit light image center position output circuit having a binarization circuit and a pulse generation circuit is provided, and a slit light beam is output from the slit light image center position output circuit that counts the horizontal synchronizing signal and outputs the scanning line number signal to the arithmetic circuit. The image center position signal is output in real time, and the distance and shape of the object to be detected are calculated at high speed by the arithmetic circuit based on the slit light image center position signal and the scanning line number signal output from the scanning line number output circuit. Detectable, improving detection performance and operational reliability.

(Operation) The image signal output from the TV camera is output as a binarized signal by the binarization circuit. In the pulse generation circuit, two signals, that is, a first pulse signal having a cycle corresponding to the horizontal resolution of the image signal and a second pulse signal having a cycle twice that of the first pulse signal, are newly reset by the horizontal synchronizing signal. Output. In the slit light image center position output circuit,
The switching output obtained by switching the first pulse signal and the second pulse signal by the binarized signal is counted for each horizontal period signal and output in real time as a slit light image center position signal. The scanning line number output circuit counts the horizontal synchronizing signal and outputs it as a scanning line number signal. It is calculated and output.

(Embodiment) One embodiment of the present invention is shown in FIG. 1 and FIG. 2, in which (a) is a detection that slit light is emitted by a slit light source (b) connected to a light source power source (c). An arithmetic circuit (4) detects an object, which is an image signal (1a) for each horizontal synchronization signal (10b) output from a television camera (1) that images an object (a) for slit light irradiation detection. In a slit light type detection device that calculates and detects the distance and shape of the object (a), a binarization circuit (11, 12) that converts the image signal (1a) into a binarized signal (12a) and a horizontal A first pulse signal (13a) that is reset by the synchronization signal (10b) and newly has a cycle corresponding to the horizontal resolution of the image signal;
Similarly, it has a pulse generation circuit (13) that outputs two signals of a second pulse signal (13b) having a period twice that of the first pulse signal (13a), and is switched and output by a binarized signal (12a). The slit light image center position to be input to the arithmetic circuit (4) by counting the first pulse signal (13a) and the second pulse signal (13b) for each horizontal synchronizing signal (10b) and forming the slit light image center position signal (16a) The output circuit (14,15,16) is provided, and the scanning line number output circuit (17,18) is provided for counting the horizontal synchronizing signal (10b) and inputting it to the scanning circuit number signal (18a) to the arithmetic circuit (4). It is a slit light type detection device.

The television camera (1) will be described in detail. The television camera (1) captures an image of a detection target (a) irradiated with slit light, and the television camera (1) includes a synchronization signal generator (10). Image pickup is started from the time when the vertical sync signal (10a) output from the
Image signal for each scan line (1a) every time b) is input
Is output.

The binarization circuit (11, 12) is a D / A converter (D / A converter that converts the binarization threshold output as a digital value from the arithmetic circuit (4) into an analog signal and outputs an analog threshold signal (11a) ( 11), analog threshold signal (11a) and image signal (1a)
And a comparator (1 that outputs a binary signal (12a) that becomes “1” if the image signal is larger and “0” if it is smaller.
It consists of 2). When the horizontal synchronizing signal (10b) is input, the pulse generating circuit (13) has a first pulse signal (13a) having a cycle corresponding to the horizontal resolution of the virtual image memory.
Are output as the first output by a number equal to the resolution,
The second pulse signal (13
b) is output as the second output by half the number of the first pulse signal (13a).

For example, if a TV camera having 480 scanning lines is used and the horizontal resolution is set to 512 pixels, it takes 1/30 seconds for a general TV camera to capture one screen. As a result, the period of the first pulse signal is 135.6 nanoseconds, and the number of output pulses is 5
12 pulses, the period of the second pulse signal is 271.3 nanoseconds, and the number of output pulses is 256 pulses.

The slit light image center position output circuit (14, 15, 16),
Switching that is reset when the horizontal synchronization signal (10b) is input and outputs the first pulse signal (13a), and when the output of the comparator (12) rises, it is switched to the second pulse signal (13b) and output (14) and a first counter (15) that clears the contents when the horizontal synchronization signal (10b) is input and that newly starts the pulse number of the pulse signal output from the switching device (14). , When the output of the comparator (12) falls, the output of the first counter (15) is latched, and as a result, when converted by the number of first pulse signals (13a) of the pulse generator (13), the comparator (12 ) Output is equal to the center of the area of “1”, that is, the center position of the slit light image, the slit light image center position signal (16
It comprises a first latch circuit (16) for outputting a).

The scanning line number output circuit (17, 18) outputs a vertical synchronization signal (1
The second counter (17) which is cleared by 0a) and counts the horizontal synchronizing signal (10b), that is, the number of scanning lines of the image.
And a second latch circuit (18) latched at the falling edge of the comparator (14) at the same time as the first latch circuit (16).
The scanning line number in which the slit light image center position signal (16a) output from the latch circuit (16) exists is simultaneously output as a scanning line number signal (18a).

Further, although the image memory (3b) to which the binarized signal (12a) is input is provided, it is not absolutely necessary in the present invention, and the image memory (3b) records a binary image. It is installed in the position shown only when necessary.

Explaining with the time chart of the slit light detection circuit shown in FIG. 2, the slit light shown in FIG. 1 is vertical on the image, and detecting the slit light detects the center position of each scanning line. Therefore, in order to obtain the center position of the slit light image, the left end P _L and the right end P _{R of the} slit light are
Can be calculated from the following formula.

Let ΔP be the difference between P _L and P _R The first pulse signal (13a), which is the first output of the pulse generator (13), is used to determine the P _L, and the signal is the same as the clock signal of the vertical edge detection circuit. Yes, and the second pulse signal (13
b) is used to obtain the ΔP / 2.

That is, it is faster to count as a signal having a frequency of 1/2 of the first output of the pulse generator in advance than to detect ΔP and divide it by 2, and the slit light image center position signal can be calculated in real time. Is obtained.

The output of the switching device (14) is the first output of the pulse generator (13), that is, the first pulse signal (until the first edge (corresponding to the left end of the slit light) on one scanning line is detected. 13
a) and thereafter outputs the second output, that is, the second pulse signal (13b) (reset by the horizontal synchronizing signal (10b)), and the first latch circuit (16) and the second latch circuit (18) , Both are latched only at the falling edge of the output of the comparator (12), and temporarily hold the corresponding counter outputs,
The slit light image center position signal (16a) is obtained in almost the same process as the vertical edge detection circuit.

The arithmetic circuit (4) calculates and detects the distance of the detection object (a) at high speed by inputting the slit light image center position signal (16a) and the scanning line number signal (18a). In addition, the shape of the detection target (a) can be easily calculated and detected accordingly.

The calculation itself is a well-known technique, and its details are omitted.

(Effects of the Invention) The present invention is configured as described above, and includes a binarized signal of an image signal, a first pulse signal having a period corresponding to the horizontal resolution of the image memory, and a double pulse period. The slit light image center position signal is obtained in real time from the slit light image center position output circuit by the second pulse signal, and the slit light image center position signal and the scanning line number signal output from the scanning line number output circuit are input. By this, the distance and further the shape of the object to be detected are calculated and detected at high speed by the arithmetic circuit, the arithmetic circuit does not need to find the slit light image center position, and there is a margin in the calculation of the distance and the processing time. Significantly shortened detection signal and operational reliability are significantly improved.

Although the present invention has been described with reference to the embodiments, the present invention is of course not limited to such embodiments, and various design modifications can be made without departing from the spirit of the present invention. .

[Brief description of drawings]

FIG. 1 is a circuit diagram of a slit light type detection device showing an embodiment of the present invention, FIG. 2 is a time chart showing the processing steps of FIG. 1, and FIG. 3 is a circuit diagram of a conventional distance measuring device. FIG. 4 is an explanatory diagram of the definition of the slit light image. 1: TV camera, 4: Calculation circuit 11, 12: Binarization circuit 13: Pulse generation circuit (pulse generator) 11,… 16: Slit light image center position output circuit 17, 18: Scan line number output circuit

 ─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-60-209105 (JP, A) JP-A-56-70407 (JP, A) JP-A-61-71303 (JP, A) JP-A-62- 239285 (JP, A)

Claims (1)

(57) [Claims] 1. A slit light for detecting a distance and a shape of the detection target by an arithmetic circuit by an image signal for each horizontal synchronizing signal output from a television camera for imaging the detection target of slit light irradiation. In the detection system, a binarization circuit for converting the image signal into a binarized signal, a first pulse signal for synchronization which is reset by the horizontal synchronization signal and newly corresponds to the horizontal resolution of the image signal, It has a pulse generation circuit that outputs two signals of a second pulse signal having a period twice that of the first pulse signal, and outputs the first pulse signal and the second pulse signal that are switched and output by the binarized signal. A slit light image center position output circuit that counts each horizontal synchronization signal to obtain a slit light image center position signal and inputs the slit light image center position signal to the arithmetic circuit is provided. A slit light detection device, characterized in that provided with the scanning line number output circuit to be inputted to the arithmetic circuit.