JPS6156582A - Automatically selective image pickup device - Google Patents

Abstract

PURPOSE:To obtain stereoscopic information and to selectively change over a plurality of photoelectric converters by dividing output signals from multiple photoelectric converting elements for picking up the forward scene into a plurarity of signal pulses each having a range of level, counting the number of pulses within each range for a predetermined period and comparing the number of pulses with the reference pulses. CONSTITUTION:Numeral nH is defined as a number of pulses having level of higher than T2 issued from counter circuit 29 for divided pulse levels in eachpredetermined interval and numeral nM is defined as a number of pulses having level between T1 and T2. When nH is larger than umber of reference pulses n1. photodetecting elements 27, 28 are passed the signals so as to pass the signals from the photodetecting elements 24-28 for the stereoscopic observa tion and only one band for observing the directly below point. When the number of pulses nMM is smaller than the preset number of reference pulses and the number of pulses nH above level T2 does not arraive at the preset number of reference pulses n1, the output signal from photocells 24-26 for performing multiband observation are allowed to pass from the output signals from photocells 24-28.

Description

[Detailed description of the invention] 〔Technical field〕 The present invention relates to an imaging device, particularly an artificial satellite or a space base.

The present invention relates to an imaging device used to observe images of the earth's surface from a space shuttle, an aircraft, or the like.

[Prior art]

Ocean information is used in so-called remote sensing, which observes conditions on the earth's surface from artificial satellites.

It is required to collect land area information (vegetation information, resource information, etc.) and other various information.

For these image observations, the requirements for observation spectrum ground resolution or level resolution are different, and for example, resource information observation requires 3D observation, etc.
Depending on the object to be imaged, the required performance often differs markedly. However, transmitting all of the information for these different observation requests at the same time is subject to limitations such as transmission bandwidth, transmission power, and data recorder recording capacity. Command command.

A method has been used in which selection is made using a code signal.

FIG. 1 is a diagram showing an example of an imaging method using these conventional imaging devices. In FIG. 1, l represents a moving body equipped with an imaging device, such as an artificial satellite, and is shown moving at a relative speed V with respect to the ground surface. 2 is an optical system for imaging the ground surface directly below the satellite, and 3 and 4 are front imaging optical systems and rear imaging optical systems, respectively, for three-dimensional observation of the ground surface.

When the artificial satellite 1 is at position A, the optical system 2 images the ground surface at a point directly below 5, and the optical systems 3 and 4 image the ground surface at a forward point 6 and a rear point 7, respectively. The satellite 1 takes images while moving at a speed V, and when it moves to the position B, the rear imaging optical system 4 detects the rear point 6 seen from the position 9B.
(That is, the same point as the forward point 6 seen from the position of A) is imaged at a different angle from the observation angle from the position of A. Then, the observation data from the optical system 4 from the position B and the above-mentioned A
Based on the observation data acquired by the optical system 3 from the position, three-dimensional information of the point 6 can be obtained.

Note that in FIG. 1, the position of the point directly below 5, which is imaged by the optical system 2, is offset from the midpoint between the forward point 6 and the rear point 7, but this is due to the distance between the satellite 1 and the earth's surface. This is because the distance H is shown relatively extremely small; in reality, the distance H is very large, and the position of point 5 is approximately halfway between points 6 and 7.

FIG. 2 is a diagram showing an example of the internal configuration of a conventional ρ imaging device. In FIG. 2, incident light from a point 5 directly below is supplied to a spectroscopic system 8 through an optical system 2.

This spectroscopic system 8 is used to divide the incident light into several wavelength bands for observation, and in this case, an example will be shown in which the light is divided into three bands for measurement.

Points 9 to 11 were placed on the imaging plane to convert optical information from the point immediately below into electrical signals. Multi-element photoelectric conversion elements such as photodiode arrays or CCDs (charge-coupled devices)
(hereinafter abbreviated as light receiving element). Incident light from the earth's surface is sent to a spectroscope 8, for example, light in the short wavelength side (visible range) is sent to a light receiving element 9, light in the intermediate wavelength range is sent to an element 10,
Light on the long wavelength side (near infrared region) is imaged onto the light receiving element 11, respectively. On the other hand, light-receiving elements 12 and 13 are similarly arranged on the focal planes of optical systems 3 and 4 for performing stereoscopic observation, and images of the front point and the rear point are respectively formed.

14 is a light receiving element 9゜10.11 for observing the point 5 directly below.
・Conversion of the signal output to be suitable for transmission to the ground,
This is a signal processing circuit that performs multiplexing, etc. Similarly, 15 is a signal processing circuit that receives signal outputs from light receiving elements 12 and 13 that perform stereoscopic observation, and performs conversion multiplexing and the like so as to be suitable for transmission to the ground.

Reference numeral 16 denotes a signal switching section. Since the data rate of transmission/recording is limited by the data recorder 17 and the transmitting section 18, data within this limited range is sent to signal processing circuits 14 and 15 in response to a selection command signal to be described later. Compare and select and output from the comparison results. The signal switching unit 16 compares the signals, and the comparison result is either temporarily recorded in the data recorder 17, or is directly supplied to the transmitting unit 18 as shown by the dotted line, and is transmitted via the antenna 19 to the receiving station on the ground. be done.

20 is an antenna for receiving commands from the ground;
A command signal from the ground is supplied to a command receiving section 21 via this antenna 20. The command receiving circuit 21 outputs a selection command signal included in the command signal from the ground and supplies it to the signal switching section 16. The signal switching section I6 thereby switches between the imaging system 2 or the imaging systems 3 and 4 as described above.
Select and switch between the image signals of the ground surface that are acquired.

As is clear from the above explanation, in the conventional device,
Since the processing of the imaged signal is performed by command signals from the ground, selection operations are only possible in areas where communication is possible from the ground command station. Furthermore, in this case, multiple optical systems were used for stereoscopic imaging, as shown in FIGS. 1 and 2.

The conditions were also disadvantageous in terms of weight and size.

In order to compensate for the above-mentioned drawbacks, there is a method in which the selection is performed after a certain period of time has elapsed after receiving the command signal, or a method in which the selection operation is programmed from the beginning and then executed. However, in none of these methods, the object to be imaged is actually observed, and therefore it is impossible to make a selection that precisely corresponds to the object to be imaged.

[Purpose of the invention]

Therefore, it is an object of the present invention to eliminate the drawbacks of these conventional devices and provide a high-quality image acquisition adapted to the imaging target with a simple configuration, a highly efficient signal processing and stereoscopic imaging ring, and a multifunctional and highly efficient imaging device. Our goal is to provide the following.

[Structure of the invention]

According to the present invention, in an imaging device that moves relative to an object to be imaged, the optical ridges for imaging in the imaging device are parallel to each other in the imaging plane and substantially relative to the moving direction of the imaging device. A plurality of multi-element photoelectric conversion elements arranged at right angles and configured to image at least the forward direction of the movement direction and the direction directly below the imaging device (front direction), and a multi-element photoelectric conversion element configured to image the forward direction. A pulse level division counting circuit divides the signal output into multiple level ranges of signals and pulses and counts the number of signal pulses within each division range for a certain period of time, and the counting output of this counting circuit is calculated according to a preset standard. a selection switching circuit that compares the magnitude of the pulse count value with the number of pulses and selectively switches the signal output of the plurality of conversion elements according to the comparison result; An automatic selection imaging device is obtained, which is characterized in that it acquires visual information and selects and switches among the plurality of photoelectric conversion elements.

〔Example〕

FIG. 3 shows an embodiment of the configuration of an imaging device according to the present invention. Components that are the same as in FIG. 1 have the same reference numerals. In this Figure 3.

This is a wide-angle optical system, directly below point 5. Front point 6
The incident light from the rear point 7 passes through this optical system 22 and is supplied to a spectroscopic system 23 . Numerals 24 to 28 are light receiving elements for converting optical information from the earth's surface into electrical signals, which are arranged at the focal plane of a wide-angle imaging optical system composed of an optical system 22 and a spectroscopic system 23. Note that in the example shown in FIG. 3, as in the case of FIG. 2, information about the point 5 immediately below is divided into three bands and observed.

For example, light incident on the spectroscopic system 23 from a point 5 just below the earth's surface is such that light in the short wavelength side (visible range) goes to the light receiving element 24, light in the intermediate wavelength range goes to the light receiving element 25, and light in the long wavelength range (near infrared range) goes to the light receiving element 25. ) are respectively imaged onto the light receiving element 26. On the other hand, in the example of FIG. 3, the light receiving elements 27 and 28 that perform stereoscopic imaging are arranged in the same imaging plane as the light receiving element 26 that performs observation in the long wavelength range. The three light receiving elements 26 to 28 are arranged substantially parallel to each other and substantially perpendicular to the traveling direction.

With the above arrangement, as shown in the figure, the light receiving element 26 has a direct point 5. The light receiving element 27 has a front point 6. An image of the ground surface at the rear point 7 is formed on each of the light receiving elements 28, and the two sets of light receiving elements 27.28 are compared, and from the data of this comparison result, a second
As in the case of the figure, three-dimensional information on the ground surface can be obtained. In addition, in the case of this method, the light receiving element 26 is also the light receiving element g7.
．． Since they are arranged parallel to each other, using the data of 26 and 27 or 26 and 28 will reduce the angle to about 1/2 of the stereoscopic viewing angle when viewing the same point, but the stereoscopic viewing angle can be obtained.

The signal output of the light receiving element 27 which performs imaging of the forward point is supplied to the pulse level division counting circuit 29.

Generally, optical observation information from space includes data on land areas, ocean areas, and clouds. When comparing the light receiving elements when capturing an image of a cloud, the comparison result signal is usually at a very high level.

This comparison result is the lowest when comparing images of ocean areas. In particular, observation using wavelengths in the near-infrared band
Different output levels can be obtained depending on the land area and clouds.

FIG. 4 is a diagram showing the output level obtained by observation using the above-mentioned wavelength in the near-infrared band, where the horizontal axis is time, and the vertical axis shows the comparison result level of photoelectric conversion elements. The photoelectric conversion element is C
In the case of OD, the comparison result signal is output in the form of PAM in which one pulse output corresponds to each pixel. Note that even if the output waveform is a continuous analog waveform, the waveform shown in FIG. 4 can be obtained by sampling.

In FIG. 4, the vicinity of level H or the vicinity of cloud 1M corresponds to land area information, and the vicinity of level L corresponds to sea area information. Therefore, as shown in the figure, the threshold values T11T2 are set near the middle between levels L and M, and near the middle between levels M and H, respectively.
By generating the threshold value of #T2 from the threshold value generating section 3o shown in FIG. The comparison result is r T 1 or less, TI = Tz
* Divided into three areas of T2 or higher, and signals within each classification range.
It is possible to count the Mars number. The counting period is performed in a preset period (for example, -scanning line period), and the counting output is supplied to the mode setting circuit 31.

In the mode setting circuit 31, the Noculus level division counting circuit 29 compares the results, and compares the comparison results with the standard number of pulses preset in this section. The imaging mode is set by making a size determination.

Reference numeral 32 denotes a selection switching circuit, which compares the signal outputs of the light receiving elements 24 to 28 from the mode setting circuit 31, compares the signal outputs of the light receiving elements 24 to 28 with analog gates that individually turn on and off, and multiplexes and multiplexes the comparison results. It consists of a circuit that

33 is a signal processing circuit, which is composed of an amplification circuit, a sample hold circuit, an AJ'D conversion, a multiplexing section, etc., and inputs the signal output from the switching circuit 32 to a recorder to be described later and transmits it to the ground. This is the part that converts the signal into a format (for example, a time-division multiplexed digital signal) that is compatible with the . In addition, the above-mentioned amplification circuit in the circuit.

The mode setting circuit 31 compares the signals, and is configured to switch the amplification rate (dyne) of the signal based on the comparison result.

Reference numeral 34 is a data recorder similar to 17, and in the case of a single-line system, a mode setting circuit 31 compares the clock frequency of the recording section according to the comparison result, and is configured to switch the recording speed. .

Next, as a specific example of imaging mode settings, in the land area, one band and stereoscopic observation of the point 5 directly below is performed, in the ocean area, multi-band observation of the point directly below is performed, and in the seismic area, data transmission is stripped. We will discuss the specific method. In order to simplify the explanation, we will introduce the stereoscopic observation in the land area mentioned above and the digital records for one band directly below.
The mode in which transmission is carried out is called the normal mode, and the higher-speed or lower-speed modes will be tentatively referred to as the high-speed mode or the low-speed mode in the following explanation.

Let the number of i4 pulses of level 72 or higher outputted every fixed period, which is also formed by the tR pulse level classification counting circuit 29, be nH+the number of pulses between levels Tl and T2 as nM.

First, if +nM as the mode of il is larger than the set reference number n1 of 9 ruses within a certain period, it is determined that there is a lot of information on the land area that is the main target, and the light-receiving element is used for stereoscopic observation. A selection control signal is given from the mode setting circuit 31 to the selection switching circuit 32 so that only the signal from the light receiving element 26 and the signal from the light receiving element 26 are passed through, for example, the signal from the light receiving element 26 to 28 is transmitted. Pass the signal. Further, in this case, the signal processing circuit 3
3 and data recorder 34 are operated in normal mode.

Next, as a second mode, the number nM of pulses between levels T1 and T2 is smaller than the set reference number n1 of pulses, and
If the number nH of pulses at level 72 or higher does not reach the set reference number n2 of pulses.

It is determined that most of the information is about the ocean area, and the mode setting circuit 3
1 and the selection switching circuit 32, the light receiving element 24 performs multiband observation from among the signal outputs of the light receiving elements 24 to 28.
~26 comparisons are made, and this comparison result signal is passed. Also,
The gain of the amplification circuit in the signal processing circuit 33 is switched to m times.

In the case of the configuration example shown in FIG. 3, the light receiving elements 24 to 26 are compared, and the data rate of this comparison result and the data rate of the normal mode in the case of land observation are the same when the number of light receiving elements to be handled is the same. Therefore, the data rates of the signal processing circuit 33 and data recorder 34 may basically be the same as in the normal mode.

If the data rate of the signal output for multi-band observation of the direct point differs from the normal mode due to the number of bands or the number of pixels, the clock speeds of the signal processing circuit and data recorder are switched according to this ratio. Furthermore, as shown in FIG. 4, changes in signals in the sea area are moderated, and data can be compressed effectively by predictive coding or the like. However, in this case, the clock speed of the signal processing circuit output and the clock speed of the data recorder are switched according to this compression ratio.

As the third mode, if the value of the number of pulses nM is smaller than nl and the number of pulses nH is greater than or equal to n2, it can be determined that most of the area is covered with clouds. All selection switching circuits 32 are turned off, and the operations of the signal processing circuit 33 and data recorder 34 are temporarily stopped. In this case, at least the front image sensor 27
By keeping the pulse level division counting circuit 29 in operation, if the above conditions of nM<J and nH≧n2 are not satisfied, it is possible to immediately shift to the first or second imaging mode. . Further, in the third mode, signal processing is performed for, for example, only one band of a point directly below or only one band of stereoscopic imaging.

It is also possible to operate the data recorder in low speed mode.

The values of the reference pulse numbers n1 r n2 and the gain m described in the above description are set from the system design results of the entire device. For example, for the total number of signal pulses n within a certain period, n
1/n=0.05 + n2/n=0.9
+ or can be set to a value of m=4. Furthermore, these values can be converted to command signals from the ground.
・It is also possible to change it and set it to an appropriate value.

Furthermore, in the first mode, the direct point observation j has been described as being for only one band, but the direct point observation is performed over a plurality of wavelength bands at values within the allowable range of data amount and speed. It is also possible.

Furthermore, in order to simplify the explanation, the configuration example in Fig. 3 shows the case where there is one optical system, but one optical system may also be used when the observation wavelength band is longer wavelength and is not configured with the same optical system. It is clear that the signal switching of the light receiving element output can be performed depending on the method.

As described above, it is possible to realize a highly efficient multi-functional imaging device adapted to the object to be imaged by using the single-wire method and by using a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of an imaging method using a conventional imaging device, FIG. 2 is a diagram showing an example of the internal configuration of a conventional imaging device, and FIG. 3 is a diagram showing the structure of an embodiment of the present invention. Figure 4 showing
The figure is a diagram showing an example of observation results using the apparatus according to the present invention. Explanation of symbols: 1 is a moving body, 1 and 8 are transmitters, 22 is an optical system, 23 is a spectroscopic system, 24 to 28 are multi-element photoelectric conversion elements (
(light receiving element), 29 is a 9-Russ level division counting circuit, 30
Reference numeral 31 denotes a threshold generation section, 31 a mode setting circuit, 32 a selection switching circuit, 33 a signal processing circuit, and 34 a data recorder. Figure 1 8 A Fan 3 Figure 1 'i', '(→

Claims (1)

[Claims] 1. In an imaging device that moves relative to an object to be imaged, the imaging devices are parallel to each other in the imaging plane of the imaging optical system in the imaging device and relative to the moving direction of the imaging device. a plurality of multi-element photoelectric conversion elements that are arranged substantially perpendicular to each other and capture images at least in the forward direction of the movement direction and in a direction directly below (front direction) of the imaging device; and a multi-element photoelectric conversion element that captures images in the forward direction. A pulse level division counting circuit divides the signal output of the conversion element into signal pulses in a plurality of level ranges and counts the number of signal pulses within each division range for a certain period of time, and the counting output of this counting circuit is calculated based on a preset standard. a mode setting circuit that compares the magnitude of the pulse count value and sets a plurality of imaging modes based on the comparison result; and a mode setting circuit that sets a plurality of imaging modes based on the comparison result; An automatic selection imaging device comprising: a selection switching circuit that selectively switches an output, and acquires stereoscopic vision information and selectively switches among the plurality of photoelectric conversion elements based on the output of the forward direction imaging device.