JPS628671A - Image input device - Google Patents

Abstract

PURPOSE:To obtain the display of an inter-frame or inter-field subtraction image or addition averaging image without requiring a special hardware for image process by using an electrostatic induction transistor image pickup device capable of non-destructive read out. CONSTITUTION:A two-dimensional image pickup device is constituted in such a way that one picture element is set comprising a pair of two SIT (electrostatic induction transistor) photodetecting elements which are positioned in adjacent upper and lower places. A device is constituted so as to connect selectively either of the two photodetecting elements to an odd field output terminal for an odd field and the other to an even output terminal for an even field. An SIT image pickup device 9 generates simultaneously an odd field output signal and an even field output signal with being driven by a control circuit 12 and a signal process circuit 10 outputs a normal image signal, an addition averaging image signal, a differential image signal a false frame image signal in parallel. A signal selecting circuit 11 selects a required image signal and supplies it to a monitor 13, displaying it on the monitor.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an image input device that displays subtracted images between frames or fields, addition average images between frames or fields, and the like.

[Conventional technology]

For images input from an imaging device such as an ITV camera, inter-frame or inter-field subtraction may be performed to obtain only moving objects, and inter-frame or inter-field averaging may be performed for the purpose of reducing noise. In order to perform these processes, a configuration as shown in FIG. 7 has been adopted as a typical conventional image input device.

In this device, analog signals for one frame outputted from an ITV camera 1 are converted into digital data by a MU/D converter 2, and #i products are stored in a frame memory 8. Next, the analog signal for one frame outputted from the ITV camera 1 is converted into digital data by the A/D converter 2, and this digital data and the data of the previous frame stored in the frame memory section 8 are combined. For example, the arithmetic processing section 4 performs addition and averaging, the D/A conversion section 5 reconverts into an analog signal, and the image obtained by adding and averaging between frames is displayed on the monitor 6. At this time, the data of the previous frame stored in the frame memory section 3 is read out for the averaging calculation in this arithmetic processing section, and at the same time, the current digital data is stored in the frame memory section 3. Thereafter, the image of the next frame is averaged with the previous image in the same way, and the averaged image between frames is always displayed on the monitor 6. It goes without saying that if the function of the arithmetic processing section is to take the absolute value of the difference rather than the arithmetic average, the difference image will be displayed on the monitor 6.

Generally, the image processing section 8 consisting of the A/D conversion section 2, the frame memory section 3, the arithmetic processing section 4, and the D/A conversion section 5 of this image input device is combined into one device, and is used as an image processing device. It is commercially available and is often used.

[Problem that the invention seeks to solve]

The conventional image input device with the above configuration requires special hardware such as the image processing unit 8, and even if other configurations are used, at least the frame memory unit 8 that stores image information is required. Hardware for storing data and hardware for performing calculations, such as the calculation processing section 4, are indispensable and are expensive.

The present invention takes advantage of the non-destructive readout feature of static induction transistor (SIT) imaging devices, and enables frame-to-frame reading without the need for conventional expensive special hardware for image processing. Another object of the present invention is to provide a compact and inexpensive image input device capable of displaying a subtracted image between yields, an average image between frames or fields, and the like.

[Means to solve the problem]

In the present invention, non-destructively readable light-receiving elements such as 5IT (static induction transistor) light-receiving elements are arranged in a matrix as an imaging device, and two adjacent SI
An IVIB element is configured with a pair of T light receiving elements, and one of the two SIT light receiving elements forming each pixel is used for odd fields and the other for even fields, and is selectively connected to the odd field output terminal and the even field output terminal, respectively. Using a SIT imaging device configured to allow the following, an odd field output signal and an even field output signal that are simultaneously output from its two output terminals are processed by a signal processing means to generate an average image signal, a difference image signal, etc. let

[For production]

According to the above-described image input device of the present invention, odd and even field output signals are simultaneously supplied from the imaging device, so that an average image signal, a differential image signal, etc. can be input without providing a conventional frame memory. image signals can be obtained, and the configuration is extremely simple and inexpensive.

〔Example〕

Figure 1 shows the arrangement of the SIT photodetector of the SIT imaging device used in the present invention. FIG. 2 is a plan view diagrammatically showing a configuration example. In the example of FIG. 1(a), two vertically adjacent SIT light receiving elements are paired as one pixel, and a two-dimensional imaging device is configured with a matrix of K (columns)×L (rows) pixels. Therefore, the number of SIT light receiving elements is K (columns)×2L (rows). Figure 1(b)
In the example, two SIT light receiving elements adjacent in the diagonal direction are paired to form one pixel. Note that, in principle, the present invention is not limited to the above-mentioned examples (a) and (1), and two adjacent elements may be paired.

In this imaging device, one of the two light-receiving elements constituting each pixel is for odd field use, and the other for even field use, so that they can be selectively connected to the odd field output terminal and the even field output terminal, respectively. Configure.

FIG. 2 is a diagram showing the principle configuration of an image input device of the present invention using such an SIT imaging device. In FIG. 2, 9 is the above-mentioned SIT imaging device, which is driven by the control circuit 12 and simultaneously generates an odd field output signal and an even field output signal at its odd field output terminal and even field output terminal. . These two output signals are supplied to a signal processing circuit 10, and this signal processing circuit converts these two output signals into a normal image signal, an average image signal, a difference image signal, and a pseudo frame image signal (each of which will be explained in detail later). Output in parallel. These image signals are transmitted to the control circuit 12
The image signal is supplied to a signal selection circuit 11 controlled by the image signal selection circuit 11, which selects a desired image signal and supplies it to the monitor 18 for display.

FIG. 8 shows an embodiment of the SIT imaging device used in the present invention. For simplicity, in this example, it is assumed that 3HxaV SIT light receiving elements 30-11 to 30-68 are arranged as shown in FIG. 2(a). That is, the light receiving elements 30-11 to 80
-18.80-31~80-38.80-51~80-
53 is a light receiving element for odd field, 30-21 to 80-
23.30-41~30-48.80-61~80-6
3 is a light receiving element for even feed, and two light receiving elements 80-11 and ao-zf, 80-12 and 80-22, ---. 30-58 and 80-61 are lI!
! Constitutes one element.

In this example, the sequential pixels arranged in a matrix with 7Wt are selected by the source gate selection method, and the output signals of the two SIT light receiving elements of the selected pixels are simultaneously read out by the source follower method. It is a thing,
Reference numeral 81 denotes a vertical scanning shift register, which includes odd field SIT light receiving elements 30- for each pixel in each row arranged in the horizontal direction.
11~80-13, +30-81~30-38.30-
Gates 51 to 30-53 and even field SIT light receiving elements 3o'-φ. 1. (i=t~8) is supplied. 8
2 is a horizontal scanning shift register, horizontal selection switch a8
-1 to 88-3 horizontal selection pulse φpi (i=1 to 8)
supply. Each of these switches 33-1 to aa-a is an odd-field light-receiving element switch SWo□ consisting of two transistors: a first transistor controlled by a horizontal selection pulse φDi and a second transistor controlled by its inverted pulse. ~swo, and switches swE for even field light reception Af-, ~swE! 8, and upon receiving the horizontal selection pulse φDi, the switches 5Woi and s
The first transistor w, 1 is turned on to connect the sources of the odd field light receiving element and the even field light receiving element of each pixel in each column arranged in the vertical direction to the odd field output terminal 36 and the even field output terminal 87, respectively. switch 5Wol while horizontal selection pulse φD1 minute is not received.
Then, the second transistor of SW8□ is turned on, and the voltage V(
V) is supplied to maintain the non-selected state. Note that the drain of the SIT light receiving element of each pixel is connected to the video voltage source 88 (vD
D), and 84 and 85 are load resistors.

FIG. 4 is a waveform diagram for explaining the operation of the SIT imaging apparatus shown in FIG. 8. As shown in the figure, the vertical selection pulses φGiO and φoix have the read voltage Vφ0 during the horizontal scanning period tH, and the vertical selection pulse φ. 1° has a reset voltage Vφ8 for every even field, and a vertical selection pulse φ. i]I
, has a υ set voltage Vφ for each odd field. In this way, the vertical selection pulse φ is generated in the odd field. □. and φ. Odd field and even field light receiving elements 30-11 of pixels in the first row by □8
30-13 and 80-21 to 80-23 are simultaneously selected, and the signals of these odd field and even field light receiving elements are output to the odd field and even field output terminals 36 by the horizontal selection pulses φI)1 tφD4 and PφD8, respectively.
and a7, after which only the even field light receiving elements 80-21 to 30-23 are reset by a reset voltage .phi., and then a pulse .phi. 2° and φ. 21
c and pulses φ□~φD8, the odd field and even field SIT light receiving elements 80-11~3 of the pixels in the second row
0-88 and 30-41 to 30-43 are sequentially read out to the respective output terminals 36 and 37, and the even field light receiving elements 30-41 to 30-43 are reset. are read out sequentially and sent to output terminal 3.
Odd field and even field output signals are obtained at 6 and 37. In the next even field, the pixels in each row are similarly read out sequentially, but in this field, only the odd field light receiving elements are reset after reading each row. In this case, the odd field of each pixel read out Jllα during the odd field is
The output signal of a field photodetector is an odd field signal component integrated over the previous one field period, and the output signal of an even field photodetector is a signal component integrated over the previous two field periods. , that is, the sum of the previous even field signal component and the odd field signal component, and
During an even field, the output signal of the even field light receiving element of each pixel becomes an even field output signal component, and the output signal of the odd field light receiving element becomes the sum of the previous odd field output signal component and the corresponding even field signal component, .

This is shown in the lower part of FIG.
−42 is shown for 0, that is, the vertical selection pulse φ. ,. ,φ. , is applied and a horizontal selection pulse φ. , is applied, the surface potential change Δ immediately below the gate of the odd field light receiving element 3 G-82 where light integration was performed over one field period before the odd field.
The surface potential change Δvllj(n-1) ” vO(
n). Therefore, 1V (t=t) = Δv0(n) On-1 VIc(t=t, n-1) = k(Δ■K(n-x)
” vO(n) ) (k is the coefficient). At this time,
The optical information of these SIT light receiving elements is not destroyed due to the non-destructive readout characteristics. After this readout, the even field light receiving element 80-42 receives a pulse φ. □ It is reset by the glue set voltage Vφ, and this light receiving element 30-42 receives new light.

Integration of the charge is started, but the odd field photodetector is not reset and continues to integrate the photocharge.

Therefore, when reading this pixel in the next even field, 1=1n, the odd field and even field output V. and V, are respectively vo(t=tn) =: k(ba b (n) + ΔvII
l(n))vlc(t=tn) ==: kΔvz(n
), and after this reading, the odd field light receiving element 30-
82 is reset and a new integration of photocharges is started, and the even field light receiving element 80-42 is not set and continues to perform optical integration.

Odd field and even field outputs v0 and v1 mentioned above
1! The following four types of images can be obtained from:

l) Normal image The output when t=tn-□, tn+1 is used as the odd field output, and 1=1n as the even field output.

If we take the output when tn+1, the odd field output is V = ΔVo (n), kΔV□ (H+1)
* ---- Even field output is v, = ΔvII! (n), Δvitn+1) t-
---, and a normal image is obtained.

g) t=tn, tn'5--- as average image odd field output
The output when t=jn- is an even field output.

If you take the output when tn+1--- and multiply it by %, the odd field output will be V=k((Δvo (n) pI, (H) )/2
) sO+ΔV k((Δvo(n+x)+ΔV]!!(H+1))/2
)*---Even field output is vz = k((7m(n-x) ``vo(n) )/
” ) *k((47m(n)+ΔVo(n+1
))/2)e---, and an averaged image between fields is obtained.

8) When difference image 1=1n-0, Δv0 to odd field output V0=
(n) and even field output v, = ΔvE(n-1)+Δ
vO(n) and b”) l 2V −V I = klJ
Vo(n) -jVmtn-g l wof'p, which is taken as the odd field output.

When t=tn, odd field output v0=k(Δv0(
n)+Δ71(H)), even field output v]! ! =
Δv8(n) to 12V, -V01=klΔvIc
(n)-ΔvO(n)l is created and this is used as an even field output. In this way, as is clear from the above equation, a difference image between fields can be obtained.

4) Pseudo frame image (frame where the odd field and even field are made up of exactly the same data) t=tn-□ 1n+0. as odd field output. Δ■ to the odd field output V0= when −−1−. (n), kvo(n+,).

--- is taken out and t=tn as an even field output.

tn+2. --- Nodokino Vo To Vx (7)
Difference VO-% = kΔv(n).

If kΔv(n+1), -1 is extracted, a pseudo frame image in which the odd field and even field are composed of exactly the same data can be obtained.

FIG. 5 shows a signal processing circuit 10 for obtaining the rtm@ described above.

In Figure 5, 40-1.40-2 is a gain expansion amplifier, 4l-1t+i-2 is a gain 2 amplifier, and 4g-1°4
2-2.42-3 is a subtracter, and 48-1.48-2 is an absolute value circuit. Output terminals 44-1 to 44 of the signal processing circuit
-8 is for odd fields, 44-4 to 44-7 are for even fields, 44-1 and 44-5 are for normal images, 444 and 44-6 are for average images, 44-
8 and 44-7 are for difference images, and 44-1 and 44-
4 is the O signal selection circuit 11 for pseudo frame images!
It is controlled by the control signal 15 from the LIIIm circuit 12, and selects a signal for obtaining a desired image from among the signals from the signal processing circuit 10 and outputs it to the output terminal 45.

In the example shown in FIG. 5, the output of the signal processing circuit is selected by the signal selection circuit 11 to output one desired image, but the output of the signal selection circuit does not need to be one. As shown in @61N, four images may be output in parallel to four output terminals 45-1-45-4.

(Effects of the Invention) As described above, in the present invention, by using a non-destructively readable SIT imaging device, the A/D converter, frame memory, and D/Ag converter, which were required in the conventional image input device, can be improved. A very compact and inexpensive IJMi image input device can be realized.
It is extremely useful as an input device when performing loop-shaped recognition of a moving object by generating a differential image in P.

[Brief explanation of the drawing]

FIGS. 1(a) and (1)) are plan views showing two examples of SIT receiver element arrays of a SIT imaging device used in the image input device of the present invention; FIG. FIG. 8 is a block configuration diagram of the device; FIG. 8 is a configuration diagram of an embodiment of the SIT imaging device used in the image input device of the present invention; FIG. 4 is a waveform diagram for explaining the operation of the SIT imaging device shown in FIG. 8; FIG. The configuration diagram of the embodiment of the signal processing circuit of the image input device shown in FIG.
The figure is a block diagram of a conventional image input device. 9...SIT imaging device lO...Signal processing circuit 1
1...Signal selection circuit 12...Control circuit 18...
・TV monitor 80-11~80-13.30-31~8O-da, f
90-51 to 80-53...SIT light receiving elements for odd field 80-21 to 80-28. aO-41~80-4
:3. aO-61 to 30-63...Even field light receiving element 81...Vertical scanning shift register 82...Horizontal scanning shift register 83-1 to 33-3...Horizontal selection switch SW N5
Wo, ... Odd field light receiving element switch l sw - sw]! , 3...Even field light receiving element switch 84.85...Load resistor 36...Odd field output terminal 37...Even field output terminal 8B...Video voltage source φ. iosφ, 1□... Vertical selection pulse φDi...
Horizontal selection pulse 40-1.40-2...gain% amplifier 41-1.4
1-2... Gain of 2 amplifiers 42-1 to 42-3...
Subtractor 48-1.48-2... Absolute value circuit Fig. 4 Fig. 5

Claims (1)

[Claims] 1. Non-destructively readable light-receiving elements are arranged in a matrix, two adjacent light-receiving elements are paired to form one pixel, and one of the two light-receiving elements forming each pixel is An imaging device that can be selectively connected to an odd field output terminal and an even field output terminal, one for odd fields and the other for even fields, and output signals from the two output terminals of the device are processed and sent to a display device. An image input device comprising: signal processing means for generating an image signal. 2. The signal processing means generates a normal image signal, an average image signal between fields, a differential image signal between fields,
Claim 1, characterized in that it comprises a signal processing circuit that generates a pseudo frame image signal in which odd and even fields are made up of the same data, and a selection circuit that selects a desired signal from these image signals. The image input device described.