JPH09196667A - Apparatus for observing surface of earth - Google Patents

Abstract

PROBLEM TO BE SOLVED: To process a vast amount of data and uniform image quality and the amount of output data, by using a discrete cosine converter, a quality coefficient-setting circuit, a quantization device, an encoder, etc., in a data- processing circuit. SOLUTION: An observation light 13 from a surface of the earth 12 is condensed at an optical system 1 and forms an image at a detector 2. The light signal is converted to an electric signal by the detector 2, and input to a data- processing circuit 3. In the data-processing circuit 3, obtained data are converted to frequency area data by a discrete cosine converter 4 and input to a quantization device 5. Meanwhile, a condition to be observed and an observation condition which are topographical information and meteological information of an observation point represented by parameters are received at a command receiver 8 as a command signal 14 from the ground. A variable with the parameters is selected at a quality coefficient-setting circuit 7, so that a quality coefficient is calculated and input to the quantization device 5. The frequency area data are operated at the quantization device 5 and the processed result, i.e., quantized data are encoded by an encoder 6 and output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an earth surface observation apparatus which is mounted on a flying object such as an artificial satellite or an aircraft to observe the surface of the earth or a planet and obtain image data.

[0002]

2. Description of the Related Art FIG. 8 is a diagram showing an example of a conventional earth surface observation apparatus. In the figure, 1 is an optical system for collecting observation light 13 from the surface of the earth 12, 2 is a detector arranged at a position where the light collected by the optical system 1 forms an image, and a detector for converting an optical signal into an electric signal, 3 is a data processing circuit for processing the signal of the detector 2 into a signal form that can be transmitted as surface image data,
Reference numeral 11 is a differential quantization circuit for compressing data in the data processing circuit, 12 is the earth, and 13 is observation light from the earth 12.

The conventional earth surface observing device is constructed as described above, and the observation light 13 emitted from the surface of the earth 12 is converted into an electric signal by the detector 2 after being incident on the optical system 1, and then by the data processing circuit 3. It was output after being processed into a form that can be transmitted as surface image data. Further, when the amount of output data generated per unit time becomes so large as to exceed the data transmission capacity, the differential quantization circuit 11 in the data processing circuit 3 is used to perform data compression. The compression performed by the difference quantization circuit 11 is a conversion operation of outputting the difference amount between the signal of the detector 2 and the data located near in the time series or the position corresponding to the ground surface. This conversion operation is generally called data compression.

FIG. 9 is a diagram showing an example of a data processing circuit including a conventional discrete cosine converter. In the figure, 3 is a data processing circuit, 4 is a discrete cosine transformer for transforming input data into frequency domain data, 5 is a quantizer for quantizing data, and 6 is an encoder for coding the quantized data. Show.

"Equation 1" is an equation for supplementarily explaining the quantization processing operation performed in the data processing circuit 3 shown in FIG. 9, and the observed signal input from the surface of the earth is the discrete cosine converter 4
Is converted into frequency domain data DCT (i, j) in the quantizer 6 and then converted into quantized data Quantized Value (i, j) in the quantizer 6 according to the equation shown in "Equation 1", and the encoder 6 Be transmitted to. Here, i and j correspond to the row and column numbers when the frequency domain data after the discrete cosine transform is displayed in a two-dimensional matrix, and are used in the same meaning below.

[0006]

[Equation 1]

[Mathematical Expression 2] is an expression showing a method for deriving the quantization matrix Quantum (i, j) used in the above [Mathematical Expression 1], and in the expression, quality is an artifact related to the compression rate and the image quality. It is a parameter that can be set dynamically and is called a quality factor. The larger the quality coefficient quality, the higher the compression efficiency and the greater the degree of image quality deterioration.

[0008]

[Equation 2]

"Table 1" is the quantization matrix Quantum.
As an example of (i, j), the case where the quality coefficient quality = 2 is shown. Note that i and j are counted from 0.

[0010]

[Table 1]

In the data processing circuit including the conventional discrete cosine transformer configured as described above, DCT (i, j) of the data after the discrete cosine transform has a lower spatial frequency corresponding to the ground surface as i and j are smaller. Since the components are shown, when the Quantum (i, j) shown in "Equation 2" is used to perform quantization by the equation of "Equation 1", the components with lower spatial frequencies are removed in the quantization stage and the true value is obtained. There was a characteristic that the error is unlikely to occur. Since the image quality of general ground surface observation data is significantly influenced by components with lower spatial frequencies, the method of FIG. 7 that removes more high-frequency components with less significance causes less deterioration in quality of output image data and It is possible to perform efficient data compression processing in which the ratio of the data output amount to the input amount is small. At this time, the quality coefficient quality shown in “Equation 2” is set to a large value as a quality coefficient when only an overview of the image is seen, and conversely, a small value is set in advance when it is desired to faithfully reproduce the details in the image. Data processing was carried out in advance. If the original image has a low contrast like an aerial photograph of a desert, the quality factor is set low, and if the original image has a high contrast such as an aerial photograph of an urban area, a high quality factor is set. If necessary, the acquired image was visually checked and then the quality coefficient was reset and data processing was performed.

[0012]

In the conventional earth surface observing device as shown in FIG. 8, the amount of data that can be reduced by the differential quantizing circuit 11 is limited to 30% of the original data at most. On the other hand, when the amount of generated data exceeds twice, there is a problem that the processing cannot be completed. Further, even when data compression is performed by a method other than differential quantization, there is a similar problem other than the method using discrete cosine transform.

In the data processing circuit including the conventional discrete cosine converter as shown in FIG. 7, the image quality and the ratio of the data output amount to the data input amount are not constant, and the features such as texture and luminance distribution of the image to be processed are characteristic. The image quality and output data depend on the difference in the topography of the observation target such as the urban area and the mountainous area, the difference in the land use situation, or the change in the brightness distribution corresponding to the weather conditions. There was a problem that the amount was non-uniform. Also"
Image quality and output data amount can be made uniform by appropriately setting the quality coefficient quality shown in Expression 2 ”depending on the characteristics of the image to be processed, but the quality coefficient qua
Since it was necessary to set the lightness in advance or to set the quality coefficient after visually checking the original image, set an appropriate value depending on the observation target when immediately processing on an aircraft or artificial satellite. It was difficult.

Further, the conventional earth surface observation apparatus mounted on an aircraft or an artificial satellite has a problem that the output image is blurred due to the influence of atmospheric fluctuation.

The present invention has been made to solve the above problems, and is capable of processing an enormous amount of data in which the amount of generated data exceeds twice the upper limit of the transmission capacity, and moreover, the terrain to be observed, It is an object of the present invention to realize an earth surface observation device in which the image quality of output data and the amount of output data are uniform without being affected by geology, land utilization status, weather conditions at the time of observation, and the like. Another object is to reduce the effect of image blurring due to atmospheric fluctuations and to acquire data with high image quality.

[0016]

According to the earth surface observing device of the present invention 1, a discrete cosine transformer, a quantizer and an encoder are provided as constituent elements for data compression operation in a data processing circuit of a conventional earth surface observing device. In addition, a quality factor setting circuit and a command receiver from the ground are installed. The command receiver receives the observation target condition x and the observation condition y, and the quality setting circuit uses the constants shown in "Equation 2" as a quality factor. qua
The variable quality (x, x, which has the observation target condition x and the observation condition y shown in "Equation 4" as parameters
y) is calculated, and the expression of "Equation 1" is replaced with the expression of "Equation 3".

"Equation 3" is an expression applied in the quantization step in the data processing circuit of the earth surface observing device of the invention 1, and is also applied to the inventions 3, 4, and 5.

[0018]

(Equation 3)

"Equation 4" is an expression applied in the quantization step in the data processing circuit of the earth surface observing device according to the first aspect of the invention, and is also applied to the fourth aspect of the invention.

[0020]

(Equation 4)

The earth surface observing device according to the second aspect of the present invention introduces a discrete cosine transformer, a quantizer and an encoder as components for performing data compression operation in the data processing circuit of the conventional earth surface observing device, and The quality coefficient setting circuit and the atmospheric correction coefficient table are provided, and after the weighting is performed in the atmospheric correction coefficient table depending on the frequency after the discrete cosine transform, the quality setting circuit uses the constant quality shown in "Equation 2" as the quality coefficient. Instead, the row i and the column j of the discrete cosine transformed matrix DCT (i, j) shown in "Equation 5"
Is calculated as a variable quality (i, j) with the parameter as a parameter.

[0022]

(Equation 5)

The atmosphere correction table is based on the experience that the effect of image blur due to atmospheric fluctuations on the surface observation data has a high correlation with the surface spatial resolution due to the vibration of the molecules in the atmosphere. The table is set so that the higher the spatial frequency, the smaller the weighting of the data by setting the larger value of quality (i, j). Matrix DC after discrete cosine transform
In T (i, j), components with higher spatial frequencies are shown as the values of i and j increase, and the influence of atmospheric molecules is i and j.
Can be set as a parameter, and therefore, in the atmosphere correction table, q can be set in the combination of i and j corresponding to the spatial frequency at which the influence of atmospheric molecules is high with i and j as parameters.
Described as setting the largeness (i, j) to a large value.

The earth surface observing device according to the third aspect of the present invention is an earth surface observing device according to the first aspect, in which an atmospheric correction coefficient table is added, and the quality coefficient is represented by "quality 4".
Instead of (x, y), row i and column j of the matrix after discrete cosine transformation shown in “Equation 5”, variable x (i, j, j) having parameters of observation condition x and observation condition y
x, y) is set in the atmosphere correction coefficient table and used in the quality coefficient setting circuit.

The atmosphere correction table has the same setting method as that of the invention 2 depending on the spatial frequency, but the distribution and kinetic energy of the molecules in the atmosphere vary depending on the observation condition x and the observation condition y. Focusing on the fact that the degree of influence of atmospheric fluctuations on the image also depends on the observation target condition x and the observation condition y, i, j, x, and y in the atmosphere correction table are noted.
As a parameter, quality (i, j, x, y)
Describe.

The distribution of molecules in the atmosphere has a high correlation with the observation target condition x such as a desert area or a dense forest area because the wet area has a higher density than the dry area. In addition, the distribution of molecules in the atmosphere is also affected by weather changes such as when the weather is fine and when it is cloudy, and the kinetic energy is strongly influenced by temperature conditions, humidity conditions, and the like, and thus has a high correlation with the observation condition y. Therefore, the distribution amount and kinetic energy of the molecules in the atmosphere are high with the observation target condition x indicating the topography, geology, land utilization status, etc. of the observation target and the observation condition y indicating the local time, meteorological condition, atmospheric condition, etc. at the time of observation as parameters. The atmospheric correction table is set so that the quality (i, j, x, y) becomes a lower value. As in the case of the second aspect of the invention, the quality (i, j, x, y) is set to a large value in the combination of i and j corresponding to the spatial frequency having a high influence of the atmospheric molecules.

The earth surface observing device according to the present invention 4 has a second detector pointing forward in the traveling direction added to the earth surface observing device shown in the invention 1, and corresponds to the histogram distribution of the data of the second detector. Variable q whose quality factor is shown in "Equation 4"
It is used as "ality (x, y)".

As a characteristic of the data acquired by the second detector, when the histogram distribution of the luminance distribution is wide and the standard deviation is large, the influence on the deterioration of the quality of the entire image is small even if a slight difference in luminance is ignored. The quality (x, y) may be set large, but if the distribution is narrow and the standard deviation is small, the quality (x, y) is set small to prevent the image quality from deteriorating. Also, regarding the spatial distribution, if the brightness variation of adjacent data is large like the observation data in urban areas,
Compared to the case where the fluctuation is small like the observation data in the mountainous area, the information of the component with high spatial frequency is more important. Therefore, in order to reduce the error factor of the high frequency component, quality
Set (x, y) small. Based on the above policy, the quality coefficient setting circuit sets quality (x, y) according to the data acquired by the second detector.

The earth surface observing device according to the present invention 5 is obtained by adding an observation condition estimating circuit and an atmospheric correction coefficient table to the earth surface observing device according to the invention 4, and the quality coefficient is a variable quality (x, y) shown in "Equation 4". ) Instead of the variable quality (i, j, x, y) shown in "Equation 6",
A quality coefficient setting circuit that sets a variable quality (i, j, x, y) weighted in the atmosphere correction coefficient table using the observation target condition x and the observation condition y set using the second detector data Is used in.

[0030]

(Equation 6)

When the data acquired by the second detector is applied to the observation condition estimation circuit, the orbit of the aircraft or satellite equipped with this earth surface observation device is known, and the observation target is determined if the observation time is determined. Assuming that identification is possible, the texture characteristics and topography classification at a specific observation point and the weather condition classification according to the brightness level in the same observation time zone are performed in advance, and then stored as a typical brightness distribution histogram of the acquired image. .

Next, in the observation condition estimation circuit, the observation time observation condition y is estimated by subjecting the luminance distribution histogram of the data acquired by the second detector to the typical luminance distribution histogram described above to estimate the observation time observation condition y. With the condition x and the observation condition y as parameters, the higher the distribution amount and kinetic energy of the molecules in the atmosphere, the higher the quality (i, j, x,
The atmosphere correction table is set so that y) becomes a low value, as in the third aspect of the invention. Also, in the combination of i and j, which corresponds to the spatial frequency at which the influence of atmospheric molecules is high, qua
It is the same as the case of the invention 2 that the lity (i, j, x, y) is set to a large value.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1. 1 is a diagram showing an earth surface observing device according to a first embodiment of the present invention, in which 1 to 3 and 12 and 13 are the same as those in FIG. 8 showing a conventional technique.
Is a discrete cosine converter for converting the signal from the detector 2 input to the data processing circuit 3 into frequency domain data,
5 is a quantizer for quantizing the processing result of the discrete cosine transformer 4, 6 is an encoder for encoding the data quantized by the quantizer 5, and 7 is for transmitting the transformed data. The quality coefficient setting circuit that sets the quality coefficient that determines the data amount and quality of the data, 8 is the command receiver that receives the topographical information and the weather information of the observation point transmitted as a command from the ground surface, and 14 is the command signal from the earth. Shown respectively. The discrete cosine transformer 4, the quantizer 5, the encoder 6, the quality coefficient setting circuit 7, and the command receiver 8 are constituent elements of the data processing circuit 3.

The earth surface observing device according to the present invention is constructed as described above, and the observation light 13 from the surface of the earth 12 is condensed by the optical system 1 and imaged by the detector 2. This optical signal is converted into an electric signal by the detector 2 and input to the data processing circuit 3 which performs a processing operation of generating ground surface image data. In the data processing circuit 3, the discrete cosine transformer 4 transforms the acquired data into frequency domain data DCT (i, j) and inputs it to the quantizer 5.

On the other hand, the command receiver 8 receives the observation target condition x and the observation condition y in which the topographical information and the weather information of the observation point are parameterized as a command signal 14 from the ground,
In the quality setting circuit 7, a variable quality whose parameters are the observation target condition x and the observation condition y in “Equation 4”
Select (x, y) and Quantum (i, j, x, y)
Is calculated and input to the quantizer 5. In the quantizer 5, the frequency domain data DCT (i, j) and Qu are calculated based on "Equation 3".
Quantized value of the quantized data of the processing result obtained by performing the arithmetic processing on the quantum (i, j, x, y)
(I, j, x, y) is encoded by the encoder 6 and output from the data processing circuit 3.

Regarding the terrain information and meteorological information, regarding the observation target condition x, for example, paying attention to the complexity of the terrain, if the flatter terrain is set to a smaller value of x, and the more complicated it is, the value of x is set. For flat terrain such as desert, x should be set small, while for large terrain such as the Rias coast or in areas with dense image changes such as dense residential areas in urban areas, set x larger. Become. Also, set x to a small value in high latitude areas, which are relatively dark even in the daytime. In this case, as the quality (x, y), the larger the x, the larger the quality (x, y) is set. In addition, when the observation condition y is focused on the ease of overlooking at a distant place, and y is set to be small under conditions where it is difficult to overlook, and y is set to be large enough for overlooking, it is possible to observe rainy season, cloudy weather, high humidity,
Y is made small under conditions such as early morning or evening hours in dark time, and conversely y is made large under conditions such as fine weather, low humidity, and high sun altitude. In this case, quality (x,
As for y), the larger x becomes, the more quality (x,
y) is set to a large value.

At this time, the image quality of the ground surface observation data is significantly influenced by the component having the lower spatial frequency, and in the quantization of DCT (i, j) of the data after the discrete cosine transform, the component having the lower spatial frequency is at the quantization stage. Since it is unlikely that the component is removed and an error with the true value is generated, the information of the low-frequency component having high significance is stored with less deterioration, and the data reduction amount increases as the high-frequency component having less significance. Further, for example, in the case of a cloudy mountain portion, in the conventional technique, the image deterioration is so severe that the data decrease amount tends to increase, and the data decrease amount is reduced and the image deterioration is suppressed in the observation target and the observation condition. Similarly, in the related art, the amount of data reduction increases in the observation target and the observation condition where the image deterioration is small but the data reduction effect is not so large.

As a result, it becomes possible to process an enormous amount of data whose generated data amount exceeds twice the upper limit of the transmission capacity. Furthermore, since the quantizer 5 removes more of the components of higher spatial frequency that have less effect on the image quality of the surface observation data, the quality of the output image data is less deteriorated, and the ratio of the data output amount to the data input amount is small. A small and efficient data compression process is possible, and the following effects are achieved at the same time in each example, and the image of the output data is not affected by the observation target topography, geology, land utilization status, weather conditions at the time of observation, etc. It is possible to control the quality and the amount of output data.

Embodiment 2 2 is a diagram showing an earth surface observing device according to a second embodiment of the present invention, in which 1 to 7 and 12 and 13 are the same as those in FIG. 1, and 9 is arranged in a data processing circuit 3. It is an atmospheric correction coefficient table.

"Equation 1" is an expression applied in the quantization step in the data processing circuit including the conventional discrete cosine converter and the data processing circuit of the earth surface observing apparatus according to the second embodiment of the present invention.

"Equation 5" is an equation applied in the quantization step in the data processing circuit of the earth surface observing apparatus according to the second embodiment of the present invention.

The earth surface observing device according to the present invention is configured as described above, and is the same as that of the first embodiment until the observation light 13 from the surface of the earth 12 is input to the data processing circuit 3. In the data processing circuit 3, the discrete cosine transformer 4 converts the acquired data into frequency domain data DCT.
It is converted into (i, j) and input to the quantizer 5.

On the other hand, the variable quality (i, j) having the parameters i and j in the "expression 5" is extracted from the atmospheric correction coefficient table 9 in which the coefficient for correcting the atmospheric fluctuation depending on the spatial frequency is described. It is input to the setting circuit 7, and in the quality setting circuit 7, Quantum (i, j) is calculated and input to the quantizer 5.

In the above atmospheric correction coefficient table 9, the degree of influence of atmospheric molecules is based on the experience that the effect of image blur due to atmospheric fluctuations on earth observation data has a high correlation with the surface spatial resolution due to the vibration of atmospheric molecules. The table is set so that the weighting of the data is reduced by setting the quality (i, j) to a larger value for the higher spatial frequency of. Image blur due to atmospheric fluctuation is as if the distant image were observed through the atmosphere, because the light rays were refracted and scattered due to the difference in air density due to the difference in temperature and the effect of wind depending on the location. This is a phenomenon in which the image fluctuates or blurs as if it were shaking. For example, an image that has been transmitted through the atmosphere varies due to refraction and scattering due to the activation of the molecular activity of water vapor, and it fluctuates as if it shakes by two adjacent pixels. If the image is blurred, it corresponds to within two adjacent pixels. By reducing the weighting of the spatial frequency component, the obtained image can be made clear. Matrix DCT (i, j) after discrete cosine transform
Indicates that the larger the value of i and j is, the higher the spatial frequency component is, and the degree of influence of atmospheric molecules can be set using i and j as parameters. In the combination of i and j corresponding to the spatial frequency with high influence of
It is described that ty (i, j) is set to a large value.

"Table 2" shows an example of the quantization matrix Quantum (i, j) calculated using the atmospheric correction coefficient table 9. In “Table 2”, i + j = 3, i + j = 4, i
This is an example of the case where the fluctuation of the atmosphere is large at the spatial frequency corresponding to + j = 5, and q when i + j is other than 3, 4, and 5.
In the case of i + j = 4, whereas weight (i, j) = 2, weighting is performed and quality (i, j) = 1
It is set to 0. It should be noted that a specific example of the correlation between the type of molecule having a large influence on image deterioration among the molecules in the atmosphere and the spatial frequency requires future study and actual measurement, and is shown here as a numerical example only. In addition, quality (i,
Since j) should also be set according to the characteristics and data amount of the actual image, quality (i, j) = 2 and quali are used as an example for comparative evaluation of the degree of influence.
ty (i, j) = 10 is illustrated.

[0046]

[Table 2]

In the quantizer 5, the frequency domain data DCT (i, j) and the Quantum (i, j) are calculated based on "Equation 1".
Quantized data of the processing result
The encoded value (i, j) is encoded by the encoder 6 and output from the data processing circuit 3.

At this time, since the weighted calculation processing is performed in the atmosphere correction coefficient table depending on the spatial frequency, the information of the spatial frequency component which is less susceptible to the fluctuation of the atmosphere is stored with less deterioration and is stored in the atmosphere. The amount of data reduction increases as the spatial frequency information is more susceptible to fluctuations.

As a result, a huge amount of data can be processed, the quality of output image data is less deteriorated, and efficient data compression processing can be performed, as in the first embodiment. Further, due to the influence of atmospheric fluctuations. The effect of blurring the image can be reduced.

Embodiment 3 3 is a diagram showing an earth surface observing device according to a third embodiment of the present invention. In the figure, 1 to 8 and 12 to 14 are the same as FIG. 1, and 9 is the same as FIG.

"Equation 6" is an equation applied in the quantization step in the data processing circuit of the earth surface observing device according to the third and fifth embodiments of the present invention.

The earth surface observation apparatus according to the present invention is configured as described above, and is the same as that of the first embodiment until the observation light 13 from the surface of the earth 12 is input to the data processing circuit 3. In the data processing circuit 3, the discrete cosine transformer 4 converts the acquired data into frequency domain data DCT.
It is converted into (i, j) and input to the quantizer 5.

On the other hand, the command receiver 8 receives the observation target condition x and the observation condition y in which the topographical information and the weather information of the observation point are parameterized as the command signal 14 from the ground,
Input to the atmospheric correction coefficient table 9.

In the atmosphere correction coefficient table 9, a variable quality (i, j, x, y) having i, j, the observation condition x and the observation condition y as parameters in “Equation 6” is extracted to set the quality coefficient. It is input to the circuit 7, and in the quality coefficient setting circuit 7, Quantum (i, j, x, y) is calculated and input to the quantizer 5.

In the quantizer 5, frequency domain data DCT (i, j) and Quantum (i, j,
x, y) is arithmetically processed, and the quantized data Quantized Value (i, j) of the processing result is encoded by the encoder 6 and output from the data processing circuit 3.

The setting method of the atmospheric correction coefficient table 9 depending on the spatial frequency is the same as that of the second embodiment, but the distribution and kinetic energy of molecules in the atmosphere depend on the observation target condition x and the observation condition y. Note that the degree of influence on the image due to atmospheric fluctuations also depends on the observation target condition x and the observation condition y because it fluctuates due to fluctuations in the atmosphere, and in the atmosphere correction coefficient table 9, i, j, x, and y are used as parameters for quality.
Describe (i, j, x, y).

Since the distribution of molecules in the atmosphere is higher in the wetlands than in the dry areas, it has a high correlation with the observation target condition x such as a desert area or a dense forest area. In addition, the distribution of molecules in the atmosphere is also affected by weather changes such as when the weather is fine and when it is cloudy, and the kinetic energy is strongly influenced by temperature conditions, humidity conditions, and the like, and thus has a high correlation with the observation condition y. Therefore, the distribution amount and kinetic energy of the molecules in the atmosphere are high with the observation target condition x indicating the topography, geology, land utilization status, etc. of the observation target and the observation condition y indicating the local time, meteorological condition, atmospheric condition, etc. at the time of observation as parameters. The atmospheric correction coefficient table is set such that the quality (i, j, x, y) becomes a lower value. As in the case of the second embodiment, the quality (i, j, x, y) is set to a large value in the combination of i and j corresponding to the spatial frequency having a high influence of atmospheric molecules.

At this time, the image reduction is suppressed and the image deterioration is suppressed in the observation object and the observation condition in which the image deterioration tends to be large in the conventional technique and the data decrease amount tends to increase in the conventional technique such as the cloudy mountainous area. Similarly, in the related art, the amount of data reduction increases in the observation target and the observation condition where the image deterioration is small but the data reduction effect is not so large. Furthermore, since the calculation processing is performed with weighting in the atmospheric correction coefficient table depending on the spatial frequency, the information of the spatial frequency component that is less susceptible to atmospheric fluctuations is saved with less deterioration, and the effect of atmospheric fluctuations is saved. The amount of data reduction increases as the information of the spatial frequency that is more easily affected.

As a result, a vast amount of data can be processed, the quality of output image data is less deteriorated, and efficient data compression processing can be performed as in the first embodiment. It is possible to control the image quality of output data and the amount of output data without being affected by land utilization conditions, weather conditions at the time of observation, etc., and it is possible to reduce the effect of blurring the image due to atmospheric fluctuations. .

Fourth Embodiment 4 is a diagram showing an earth surface observing device according to a fourth embodiment of the present invention. In the figure, 1 to 7 and 12 to 14 are the same as those in FIG. 1, and 10 is the light collected by the optical system 1. A second detector, which is arranged at a position where an image is formed, is oriented in the forward direction of the traveling direction rather than the directing direction of the first detector 2 and converts an optical signal into an electric signal, and 15 is an earth surface observation from the forward direction of the traveling direction. Light. In the quantization, "Equation 1" and "Equation 4" are applied.

FIG. 5 is a diagram showing an example of a histogram of the luminance distribution, in which 17 is an example of an image and 18 is a histogram showing the luminance distribution of the above 17 examples of images. Further, 17a and 18a are examples of images in which the luminance distribution is concentrated in low luminance, and 17b and 18b are examples of images in which the luminance is widely distributed.

In the present invention, the part of the earth surface observing device shown in the first embodiment which receives a command from the ground and sets parameters is replaced by the second detector 10 pointing forward in the traveling direction. , The quality coefficient corresponding to the histogram distribution of the data of the second detector 10 is "Equation 4"
It is used as the variable quality (x, y) shown in. As a feature of the data acquired by the second detector 10, when the distribution of the histogram of the luminance distribution is wide and the standard deviation is large, the influence on the quality deterioration of the entire image is small even if a slight difference in luminance is ignored. x, y) may be set large, but if the distribution is narrow and the standard deviation is small, quality (x, y) is set small to prevent image quality deterioration. Also, regarding the spatial distribution, when the brightness variation of adjacent data is large like the observation data in urban areas, the information of the components with high spatial frequency is more important than the case where the variation is small like the observation data in the mountains. ,
In order to reduce the error factor of the high frequency component, quali
Set ty (x, y) small. Based on this policy, the quality coefficient setting circuit 7 sets quality (x, y) according to the data acquired by the second detector 10. The operation other than the above is the same as that of the first embodiment.

As a result, as in the first embodiment, a huge amount of data can be processed, the quality of the output image data is less deteriorated, and efficient data compression processing can be performed. It is possible to control the image quality of output data and the amount of output data without being affected by the utilization status and weather conditions at the time of observation.

Embodiment 5. 6 is a diagram showing an earth surface observing device according to a fifth embodiment of the present invention, in which 1 to 7 and 12 to 14 are the same as FIG. 1, and 10 and 15 are the same as FIG. "Number 1" in quantization
And "Equation 6" are applied.

FIG. 7 is a diagram for explaining the operation of estimating the observation condition y in the observation condition estimation circuit 16. In the figure, 10 is a second detector, 16 is an observation condition estimation circuit,
Reference numeral 19 is an artificial satellite or an aircraft equipped with this device.

In the present invention, in the earth surface observing device shown in the third embodiment, the part where the command is received from the ground and the parameter is set is replaced by the second detector 10 pointing forward in the traveling direction. , The quality factor corresponding to the histogram distribution of the data of the second detector 10 is "Equation 6"
It is used as a variable quality (i, j, x, y) shown in.

Next, the operation of processing the data acquired by the second detector 10 in the observation condition estimation circuit 16 will be described with reference to FIG.
This will be described with reference to FIG. In the present invention, the orbital conditions of the aircraft or artificial satellite equipped with the present earth surface observation device are known, and it is assumed that the observation target can be specified by determining the observation time, and the features of the topography and texture at the specific observation point are classified in advance. The observation target condition table is recorded, and the corresponding observation target condition x is selected from the table based on the orbital condition and the observation time at the time of observation. As examples of topography and texture, uniformly flat desert areas, flat plains, etc. are typical classifications as examples with few high frequency components in the spatial frequency of the image, while rias coasts and urban areas with dense buildings Etc. are examples in which the ratio of high frequency components is large.

On the other hand, since the observation latitude and the incident angle of sunlight are determined based on the orbital conditions and the observation time, the luminance distribution in fine weather can be estimated, and this is recorded as a typical luminance distribution histogram. Furthermore, the spatial frequency dependence of the luminance distribution is recorded by performing a discrete cosine transform of the typical luminance distribution under the observation target condition x and viewing it in the spatial frequency domain.

Next, the observation condition estimation circuit 16 estimates the observation condition y at the observation time by performing a difference process between the luminance distribution histogram of the data acquired by the second detector 10 and the above typical luminance distribution histogram. .
As an example of the estimation, it is estimated that "if there is a decrease in brightness, it is bad weather or cloudy weather.""If very high brightness data is added, there are clouds or snow." It can be estimated that "if the ratio of high-frequency components decreases, the amount of distribution of molecules in the atmosphere and the kinetic energy are high, which causes image blur."

Using the observation condition y and the observation target condition x as parameters, the atmospheric correction coefficient table is set so that the higher the distribution amount of molecules in the atmosphere and the kinetic energy, the lower the quality (i, j, x, y) becomes. The setting is the same as in the third embodiment. In addition, in the combination of i and j corresponding to the spatial frequency with high influence of atmospheric molecules, quali
Setting ty (i, j, x, y) to a large value is the same as in the second embodiment. The operation other than the above is the same as that of the third embodiment.

As a result, a large amount of data can be processed as in the third embodiment, the quality of output image data is not deteriorated,
Efficient data compression processing is possible, and it is possible to control the image quality and output data amount of output data without being affected by the topography, geology, land utilization status, weather conditions at the time of observation, etc. Moreover, it is possible to reduce the effect of blurring the image due to the effect of atmospheric fluctuations.

[0072]

According to the present invention, the image quality of output data and the amount of output data can be made uniform without being influenced by the topography, geology, land utilization status, weather conditions at the time of observation, etc.
Further, it becomes possible to process a huge amount of data whose generated data amount exceeds twice the upper limit of the transmission capacity. Further, the influence of the surface observation data on the image quality is reduced as much as the component of higher spatial frequency with less significance is removed. Therefore, the quality of the output image data is less deteriorated and the ratio of the data output amount to the data input amount is small. A compression process becomes possible.

According to the present invention, it is possible to reduce the effect of blurring an image due to the effect of atmospheric fluctuations. Further, it is possible to process a huge amount of data, the quality of output image data is less deteriorated, and the efficient data compression processing in which the ratio of the data output amount to the data input amount is small becomes possible.

According to this invention, the topography, geology,
The image quality of the output data and the output data amount can be made uniform without being affected by the land utilization situation, the weather condition at the time of observation, etc., and the influence of the fluctuation of the atmosphere can reduce the effect of blurring the image. Further, it is possible to process a huge amount of data, the quality of output image data is less deteriorated, and the efficient data compression processing in which the ratio of the data output amount to the data input amount is small becomes possible.

According to the present invention, the terrain, geology,
Output data with uniform image quality and output data amount can be automatically acquired without being affected by land utilization conditions, weather conditions at the time of observation, etc. without ground processing. Further, it is possible to process a huge amount of data, the quality of output image data is less deteriorated, and the efficient data compression processing in which the ratio of the data output amount to the data input amount is small becomes possible.

According to the present invention, the topography, geology,
Image quality and output data volume are made uniform without being affected by land use conditions and meteorological conditions at the time of observation, and the output data that has reduced the effect of image blurring due to atmospheric fluctuations is automatically output without ground processing. Can be acquired. Further, it is possible to process a huge amount of data, the quality of output image data is less deteriorated, and the efficient data compression processing in which the ratio of the data output amount to the data input amount is small becomes possible.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of an earth surface observation apparatus according to the present invention.

FIG. 2 is a diagram showing a second embodiment of an earth surface observation apparatus according to the present invention.

FIG. 3 is a diagram showing a third embodiment of the earth surface observing device according to the present invention.

FIG. 4 is a diagram showing a fourth embodiment of the earth surface observing device according to the present invention.

FIG. 5 is a diagram showing a histogram of luminance distribution according to the fourth embodiment of the present invention.

FIG. 6 is a diagram showing a fifth embodiment of the earth surface observing device according to the present invention.

FIG. 7 is a diagram showing an observation condition estimation circuit according to a fifth embodiment of the present invention.

FIG. 8 is a diagram showing an example of a conventional earth surface observation apparatus.

FIG. 9 is a diagram showing an example of a data processing circuit including a conventional discrete cosine converter.

[Explanation of symbols]

1 optical system, 2 detector, 3 data processing circuit, 4 discrete cosine converter, 5 quantizer, 6 encoder, 7 quality coefficient setting circuit, 8 command receiving circuit, 9 atmospheric correction coefficient table, 10 second Detector, 11 Differential quantization circuit, 12 Earth, 13 Observation light from earth surface, 14 Command signal from earth, 15 Earth surface observation light from traveling direction.

Claims (5)

[Claims] 1. An optical system for collecting observation light from the surface of the earth, a detector for converting the light collected by this optical system into an electric signal, and processing the signal of the detector to generate surface image data. In the earth surface observing device including a data processing circuit, the data processing circuit is a command receiver for receiving topographical information and weather information of the surface observation point as a command signal from the ground, and the output of the detector is frequency domain data. Discrete cosine converter for converting to, a quality coefficient setting circuit that sets the quality coefficient that determines the data amount and quality when transmitting the converted data according to the output of the command receiver, according to the quality coefficient An earth surface observing device, comprising: a quantizer for quantizing data, and an encoder for coding the quantized data. 2. An optical system for collecting observation light from the surface of the earth, a detector for converting the light collected by this optical system into an electric signal, and processing the signal of the detector to generate surface image data. In the earth surface observing device including a data processing circuit, the data processing circuit is a discrete cosine converter for converting the output of the detector into frequency domain data, and a coefficient for correcting atmospheric fluctuations depending on the spatial frequency of the observation point. An atmospheric correction table that describes and weights the output of the discrete cosine converter, and a quality coefficient setting circuit that sets a quality coefficient that determines the data amount and quality when transmitting data according to the output of the atmospheric correction table. An earth surface observing device comprising: a quantizer for quantizing data according to the quality coefficient; and an encoder for coding the quantized data. 3. An optical system that collects observation light from the surface of the earth, a detector that converts the light collected by this optical system into an electrical signal, and a signal of the detector is processed to generate surface image data. In the earth surface observing device equipped with a data processing circuit, the data processing circuit is a command receiver that receives weather conditions and geographical information of the surface observation points as command signals from the ground, and atmospheric fluctuations according to the output of the command receiver. The atmospheric correction table describing the coefficient for correcting the above, the discrete cosine converter for converting the output of the detector into the frequency domain data, and the quality coefficient for determining the data amount and the quality when transmitting the converted data are corrected for the atmospheric correction. Quality coefficient setting circuit for setting corresponding to output of table, quantizer for quantizing data according to quality coefficient, and encoder for coding quantized data An earth surface observing device comprising: 4. An optical system that collects observation light from the surface of the earth, a first detector that vertically points the ground surface, and a second detector that points forward from the viewpoint of the first detector, A data processing circuit for processing the signal of the detector to generate surface image data, the data processing circuit, wherein the data processing circuit converts the output of the first detector into frequency domain data. A cosine converter, a quality coefficient setting circuit that sets a quality coefficient that determines the data amount and quality when transmitting the converted data according to the histogram distribution of the data acquired by the second detector, An earth surface observing device comprising: a quantizer that quantizes data in accordance therewith; and an encoder that encodes quantized data. 5. An optical system that collects observation light from the surface of the earth, a first detector that vertically points the ground surface, and a second detector that points forward from the viewpoint of the first detector, And a data processing circuit for processing signals of the detector to generate surface image data, the data processing circuit converting the output of the first detector into frequency domain data. A converter, an observation condition estimation circuit for estimating an observation condition from the output signal of the second detector,
Atmospheric correction table that describes the coefficient that corrects atmospheric fluctuations according to the output of the observation condition estimation circuit, and the quality coefficient that determines the data amount and quality when transmitting the converted data according to the output of the atmospheric correction table. An earth surface observing device comprising: a quality coefficient setting circuit to be set according to the above; a quantizer for quantizing data according to the quality coefficient; and an encoder for coding the quantized data.