JPS59113521A - One-dimensional image picking-up storage device - Google Patents

Abstract

PURPOSE:To scan the overall region of an object in a free range, by arranging a slit matched to the length and the inclination of an objective gap, a photosensor, and a galvanometer in an optical path and changing the driving current of the galvanometer to compensate its nonlinearity. CONSTITUTION:A hole 11a of a slit 11 is slightly shorter than the length of the image of the gap and inclines at an angle theta, and the angle theta is equal to the angle of inclination of a head gap 4. A received light is converted to a voltage output SiG by a photosensor 12 and an amplifier 13. The output SiG is converted to digital data MDI and is inputted to a waveform storage circuit 15 where a video signal is stored. A waveform generating circuit 18 receives operation command data CMD designating the center position and the amplitude of deflection of the galvanometer from a CPU20 and outputs an address ADR of the storage circuit 15 and data GD which is synchronized with this address and controls the deflection angle of a galvanometer GM9. Data GD is subjected to D-A conversion and is supplied to the galvanometer GM9. Current data GD, which is so corrected that the relation between the deflection angle theta of the galvanometer GM and the output ADR of a counter circuit is perfectly proportional, is programmed in a PROM of the circuit 18.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a one-dimensional image capture and storage device for scanning optical images, laser beams, etc., and is particularly applicable to video tape recorders that require high precision and a wide field of view. This invention can be applied to a device that automatically recognizes the center position of the head gap in the process of attaching a magnetic head (hereinafter referred to as head) of a VTR to an upper cylinder.

Conventional configuration and its problems Galvanometers are made so that the current and deflection angle of the mirror are proportional, but the actual characteristics are 2 to 3 times larger than the ideal straight line B, as shown by curve A in Figure 1. It has a percent non-linearity and some hysteresis. Therefore, in an attempt to increase the deflection angle of the galvanometer in proportion to time, an analog circuit generates a triangular wave current with good linearity to drive the galvanometer, but due to the non-linearity of the galvanometer, the deflection of the mirror is not accurate. Unable to control angle.

On the other hand, a television camera is generally used as a sensor for image recognition, but since the resolution of the television camera is limited, if you try to project the thin gap of the VTR head on the television screen, the field of view will be narrowed, and the opposite will occur. However, there was a problem in that when the field of view was wide, the gears and gears could not be seen.

Purpose of the Invention The present invention uses a galvanometer as a scanning means for the optical image of an image recognition sensor that requires a wide field of view and high resolution as described above, corrects the nonlinearity that is a drawback of the galvanometer, and corrects the nonlinearity within the scanning range. It is an object of the present invention to provide a one-dimensional imaging storage device which can enlarge any part and which can store -dimensional image information.

Structure of the Invention The present invention uses an elongated slit that matches the length and inclination of the gap whose position is to be recognized, and creates an optical path through which the intensity signals of light from the surface of an object such as a magnetic head are received by seven optical sensors. An optical system has a galvanometer placed inside, and by changing the drive current of this galvanometer, it is possible to scan the entire area of the object in a free range, and a one-dimensional image obtained as the output signal of this photosensor. It consists of an A-D converter that converts signals into digital values, a waveform generation circuit that controls the deflection angle of the galvanometer, a waveform storage circuit that sequentially stores video signals in correspondence with the deflection angle, and a clock pulse oscillator. The waveform generation circuit has a plurality of internal programmable read-only memories (
The output of this counter is given as the address of FROM and the waveform storage circuit, and the contents of FROM are programmed so that the deflection angle of the galvanometer and the output of the counter are proportional. It is a one-dimensional imaging recording device that converts the output of this FROM from digital to analog and supplies it as a drive current for a galvanometer.
It is possible to obtain a gap video signal with a good S/N ratio in a wide field of view and as a video signal without image distortion.Description of EmbodimentThe following is an embodiment of the present invention shown in Figs. 2 to 9. This is explained by: In Figure 2, 1 is the upper cylinder of the VTR, 2 and 2a are the head bases, and the heads 3 and 3a are respectively fixed to 0. There is a gap 4 at the tips of the throats 3 and 3a, and from the front When you look at it, it looks like Figure 3. To adjust the head gap position, adjust the mounting position of the throat base relative to the upper cylinder so that the center of the gap between the left and right heads overlaps the center line HH' axis of the upper cylinder in Figure 2. Do this by making small movements. In Figure 2, 6 is a beam splitter,
6 is a glass fin (-1 is a light source, 8 and 8a are convex lenses, 9 is a galvanometer and shows the mirror part. 11 is a pickpocket and a strike, and the length of its child L11a is slightly longer than the length of the image of the gap. It is short and tilted at an angle of θ degrees with respect to the vertical direction as shown in Fig. 4, and this angle θ is the same as the inclination angle θ of the headgear and knob 4 with respect to the vertical direction in Fig. 3.The slit width is the same as that of the convex lens. This is approximately the width of the gap formed by magnifying the image at 8. 12 is an odosensor (such as a photomultiplier tube). The slit 11 is arranged at a position where the image of the throat is formed by the convex lens 8. When the mirror of the galvanometer 9 rotates, the image of the head also moves in the horizontal direction, so when the galvanometer is moving, the light that passes through the entire slit 11 and enters the photo sensor is as if the head surface were the slit hole 11a. xx in Figure 3
The result is a slit light component that looks like it traces a line. Therefore, the intensity of this light is outputted from the photo sensor 12 as a signal containing noise components such as roughness and uneven brightness on the head surface, as shown in FIG. In FIG. 5, the point Xp of the lowest signal level in the part shaped like ■ is the coordinate of the center position of the gap. Note that 10 is an optical filter, which is placed in front of the photosensor in order to reduce the influence of ambient light.

In order to recognize the position of the gap from the video signal obtained in the manner described above, it is convenient to store it temporarily.The circuit configuration of the embodiment will be explained below with reference to FIG. The received light is converted into a current by the photosensor 12, and then amplified by the amplifier 13 to produce a voltage output S corresponding to the intensity of the light.
Converted to iG. Analog-to-digital converter (hereinafter abbreviated as A-D converter) with high-speed instantaneous value of voltage output SiG
The data is converted into digital data MDI and input to the waveform storage circuit 15 that stores the video signal. On the other hand, the clock oscillator 16 generates a clock pulse CLK and sends it to the timing control circuit 17. As will be explained in detail later, the timing control circuit 17 outputs an A-to-digital conversion command pulse T1, receives an A-to-D conversion end pulse T2, and outputs a write command pulse T3 for the A-to-digital converted data MDI. This is what is output.

The clock pulse CLK is also input to the waveform generation circuit 18. The waveform generation circuit 18 receives operation command data CM from the arithmetic and control unit 2° that specifies the center position and amplitude of the galvano deflection.
D and the start signal 5TAi, it outputs the address ADH of the waveform storage circuit 15 and data GD for controlling the deflection angle of the galvanometer in synchronization with the address ADH. This GD
is converted into an analog voltage by a digital-to-analog converter (hereinafter abbreviated as DA converter) 19 and supplied to the galvanometer 9 . 2o is an arithmetic and control unit (hereinafter abbreviated as CPU) such as a microcomputer equipped with a memory circuit and an input/output interface, which reads data written in the waveform memory circuit 15 via control buses ADD and MDO, and reads the data written in the waveform memory circuit 15 via the control buses ADD and MDO. The coordinates of the gap position xp are recognized as the address of the waveform storage circuit.

FIG. 7 is a diagram for explaining in detail the circuit configuration of the waveform generation circuit 18, in which 21 is a 3-bit decoder circuit, 22 is an R-S flip-flop circuit, 23 is a gate circuit, and 24 is a 3-bit decoder circuit.
25 is a rising differential circuit, 25 is an 11-bit binary counter circuit, ROM1U-ROM5L is 2048
(abbreviated as ROM), an Intel 2716 equivalent product can be used. This PROM1, ROM1U and ROM1L 1
The current GI of the galvanometer and the control signals C0NT and END are programmed in the set, and similarly, the other four sets of F, ROM2U and ROM2L, ROM3U and ROM3L, ROM4U and ROM4L, ROM6V and ROM6L, are programmed.
It is also programmed into ROM.

(Figure 7 f14 ROM3U, ROM3L, ROM4U
and ROML have been omitted due to space limitations. ) The contents are such that the C0NT signal is ON at addresses 1 to M, the END signal is ON at addresses N (where M<N), and the GI signal shown in Figure 8 is at addresses 1 to N. Data is programmed to generate a current waveform like this. and the current G
Since the relationship between I and the deflection angle θ is nonlinear as shown in FIG. 1, the relationship between the deflection angle θ of the galvanometer and the counter circuit 25 is
Program the current data GD that has been corrected so that the relationship between the output ADRo and the ADR10 is completely proportional.
Of the s group of FROMs, ROM1U and ROM1L contain data that scans the maximum deflection angle of the galvanometer between -θm and +θm, and ROM2 contains data that is corrected to scan the range C, which is one quarter of the total scanning range. data has been programmed. Similarly, ROM3U and ROM3LK have a range of D, and ROM4U and ROM4L have a range of E.
U and ROM6LK are programmed with data to scan the range of F. As a result of this configuration, it is possible to partially expand the recognition field of view, resulting in a VT with four times the accuracy.
You will be able to recognize the R head ganop position.

Next, the procedure for writing data into the waveform storage circuit 15 will be explained in detail with reference to FIGS. 7' to 9.

The clock pulse CLK is constantly output.

At the start of data writing, the CPU 20 turns off the operation command CMD and the R/W signal f. The R/W double signal is a signal that controls the waveform storage circuit 16. When it is ON, the waveform storage circuit is in a read mode, and when it is OFF, it is in a write mode, and writing to the waveform storage circuit 15 is possible only in the write mode. On the other hand, when the operation command data CMD is set to 1, the decoder circuit 21 decodes ROM1U and ROMI L.
The signal C81 for selecting is turned ON, and a state is reached in which a triangular wave-shaped current GI represented by t1 to t2 in FIG. 8, in which the deflection angle θ has the maximum amplitude, can flow through the galvanometer.

Next, when the write start pulse signal STA is output from the opu 20, the counter circuit 25 is reset via the inverter 26, and then the flip-flop circuit 22 is set at the fall of the STA signal, the gate circuit 23 is opened, and the clock CLK The output of the counter circuit 25 increases by one every time . As mentioned above, counter circuit 2
When the output of 5 is 1 to M, the C0NT signal of ROMIU is O.
It is programmed to be N. This C0NT signal is a control signal for activating the operation of the timing control circuit 1, and only when ON, A-D conversion and writing to the waveform storage circuit 15 are possible.On the other hand, the counter circuit 2
The output ADRO-ADR 10 of 6 is also connected to the write address of the waveform storage circuit 15. When the clock CLK is input, the timing control circuit 17 generates an A-D conversion command pulse T at the rising edge of the clock pulse CLK as shown in FIG.
1, and after the conversion time Δτ of the A-D converter 14, A
- Upon receiving the D conversion end pulse T2, a write pulse T3 for the waveform storage circuit 15 is output at the falling edge of T2. Therefore, the addresses 1 to M of the waveform memory circuit 16 are filled with galvanometers, or t1 to M in FIG.
One-dimensional image information such as t2 on the surface of the VTR head is written. As mentioned above, the content GD of the FROM is programmed so that the deflection angle of the galvanometer is completely proportional to the address of this waveform storage circuit. Therefore, if the arithmetic and control unit (CPU) recognizes and calculates in which part of the addresses 1 to M of the waveform storage circuit 15 the head gap position This is a good position for correcting the straight line and correcting the gap. Since address N of FROM is programmed so that the write end signal pulse END is output, by receiving the END signal, the CPU can know that writing to the waveform storage circuit 15 has ended. Further, the flip-flop circuit 22 shown in FIG. 7 is reset by the END signal, and the waveform generating circuit 18 returns to its initial state. Upon receiving the END signal, the CPU sets the R/W signal to 0FFL, switches the waveform storage circuit to the read mode, and performs the recognition calculation.

In this recognition calculation, the purpose is to get an idea of where the gap xp exists in the entire scanning range C, D, E, F of the galvanometer, and it is important to perform the calculation simply and quickly, and accuracy is not so important.

When this recognition calculation recognizes that it is in the scanning range D as shown in Figure 8, CPU sets the operation command data CMD = 3 at t3 to t4, and flows a current like GI2 to the galvanometer to change the waveform again. One-dimensional video information data with quadruple precision limited to the range D is written into the storage circuit 16. The obtained video information is 4 times more accurate data, so the CPU performs detailed recognition calculations based on this data.
This means that the position xp of the gap can be calculated with high accuracy.

Although a 2048 x 8 bit FROM is used, the present invention is not limited to this, and the number of FROMs used is not limited to 5 sets. Further, even if the oscillation frequency of the clock pulse oscillator changes due to the influence of temperature, etc., there is a one-to-one relationship between the write address of the waveform storage circuit 15 and the obtained video signal, so there is no influence.

On the other hand, the shape of the slit hole was made into the shape shown in Figure 4 because the object of recognition was a long and narrow gap, but if the object is half-moon-shaped, the shape of the slit hole may also be half-moon-shaped. Change the shape of the slit hole according to the
The S/N ratio of the video signal can be improved.

Effects of the Invention According to the present invention, a video signal is input to the photo sensor through a long and narrow slit corresponding to the width of the gap and the inclination θ. The S/N ratio was improved. Furthermore, by configuring the drive current of the galvanometer for deflecting the light passing through this slit to be programmable using FROM, even if the relationship between the deflection angle of the galvanometer and the drive current is non-linear, the waveform memory circuit can be A proportional relationship can be established between the address and the deflection angle, and an enlarged video signal can be obtained for an arbitrary range of the head. As a result, high-resolution, high-precision one-dimensional information without image distortion can be stored in the waveform storage circuit.

[Brief explanation of drawings]

Figure 1 is a characteristic diagram of galvanometer drive current and deflection angle, Figure 2 is a layout diagram of the optical system for converting the tip of the magnetic head of the upper cylinder of a VTR into a one-dimensional video signal, and Figure 3 is an enlarged plan view of the tip of the magnetic head, FIG. 4 is an explanatory diagram of the slit, FIG. 6 is a diagram of changes in the output of the photosensor when an image of the tip of the magnetic head is scanned and captured through the slit, and FIG. Figure 6 is a block diagram of the circuit configuration of an embodiment of the present invention, Figure 7 is a detailed circuit diagram of the same waveform generation circuit, and Figures 8 and 9 are timing charts for writing data to the waveform storage circuit. be. 4...VTR magnetic head gap, 9...
Galvano mirror 111...Slit, 12...Photo sensor, 14...A-D converter, 16...
... Waveform storage circuit, 16 ... Clock oscillator, 17
Timing control circuit, 18... Waveform generation circuit, 19.
・・・DA converter, 2o・ Arithmetic control unit, 21...
...Decoder circuit, 26...Counter circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
Fig. Y' Fig. 4 ρ Fig. 5 p

Claims (3)

[Claims] (1) A galvanometer whose deflection angle can be changed by electric current is placed in the optical path, and the object is positioned at the image formation position. an optical system configured to receive light that has passed through the slit with seven photosensors; an analog-digital converter that converts the photosensor output signal into a digital value; and a clock pulse generator that generates clock pulses. an oscillator, a counter circuit that counts the clock pulses, a waveform storage circuit that uses the output of the counter circuit as a write address and the output of the analog-to-digital converter as write data, and a readout that uses the output of the counter circuit as an address. a dedicated memory circuit, a digital-to-analog conversion circuit that converts the output of the read-only memory circuit from digital to analog and supplies it to the galvanometer as a driving power source; A one-dimensional imaging storage device comprising a timing control circuit that controls write timing of a waveform storage circuit. (2) The one-dimensional imaging storage device according to claim 1, wherein the hole of the slit has the same shape and size as an image of the recognition object formed on the slit. (3) The one-dimensional read-only memory circuit according to claim 1, wherein the read-only memory circuit is constituted by a plurality of sets of read-only memories and a decoder circuit that receives an external command signal and selects one of the sets. Image storage device 0