JPS6147522A - Image processing apparatus - Google Patents

Abstract

PURPOSE:To perform a coloring image processing in a real time and to facilitate operation by miniaturization and wt. reduction, by successively re-constituting an image by extracting correlation wt. on the basis of the reflection signal corresponding to pixel. CONSTITUTION:A level discrimination circuit 3 receives an input signal Slambda2 and sends the same to an AND circuit 7 while performs level discrimination in a scanning order at every pixel. Next, a level discrimination circuit 4 receives an input signal Slambda1 at every pixel and outputs the said signal while performs level discrimination to send the same to the AND circuit 7. A divider circuit 5 has function for imparting a condition determining the upper bottom of a trapezoidal intensity distribution region B from the origin 0 of intensity correlation coordinates to the region indicated by said two condition processings and sends the output after level discrimination to the AND circuit 7. By this method, three condition processings limiting the intensity distribution region are performed and an AND condition is formed when the obtained outputs are simultaneously applied to the AND circuit 7 and applied to an output terminal 602 as a green in dication signal which is, in turn, sent out to a color display circuit through the output terminal 602 to display the intensity region B in a state colored by green.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an imaging device that measures the reflectance of a target by wavelength using laser light in a spectral range from ultraviolet to far infrared rays and measures the radiant energy emitted by the target by wavelength. After calculating the correlation of the input signals by wavelength for each pixel of the target, we develop the multiple images obtained by the input signal intensity corresponding to each wavelength of each pixel on the correlation strength coordinates, and then calculate the target on these coordinates. The present invention relates to an imaging device that performs high-contrast target extraction using a so-called multispectral video, in which an arbitrary color is associated with a characteristic region of each object, including coloring, and the colors are combined and reproduced as a video.

Laser light with multiple wavelengths specified in advance is projected onto the irradiation field including the target, or radiant energy emitted by each object existing within the imaging field of view including the target is received for each wavelength.
After performing reflectance measurement or wavelength-specific radiant energy measurement, multiple images obtained corresponding to the signal intensity of each wavelength obtained for each pixel in the field of view are developed on intensity correlation coordinates for each wavelength. By associating an arbitrary color with each object's presence area in the irradiation field expressed on these coordinates and combining it again as an image, a color image is obtained in which the target is emphasized with a color that specifies the target. So-called multispectral imaging devices for high-contrast target extraction have recently become well known in the field of remote sensing.

Such multispectral imaging devices are divided into two types: one is to project a laser beam toward a target and obtain an image using a so-called active method, and the other is to obtain an image based on the radiant energy emitted by the target, which is a so-called passive method. However, in the case of the active method, for example, images are obtained in the following manner.

In other words, laser beams with wavelengths in multiple spectra set in advance from the ultraviolet to infrared spectral range are transmitted, irradiated onto the target, and the reflected light is received, and the target is sequentially scanned while corresponding to each pixel. do. Next, the desired image is created by collecting the reflected light from the scanned target, converting these f and it electric signals, and then performing predetermined arithmetic processing for each pixel and synthesizing these wavelength-specific images as an image output. It has gained.

In the above-mentioned method, the projection light to the target is usually a laser beam as excitation light, which is converted into laser beams of a plurality of predetermined wavelengths via a wavelength converter, and the projection light having a predetermined beam angle is sent to the target by the light transmission optical system. irradiate. This projected light is
For example, the target irradiation range is scanned in pixel-by-pixel directions in the horizontal and vertical directions via an optical system controlled by a combination mechanism such as a Norculus motor and an encoder.

The reflected light obtained by such scanning light projection is received through the light receiving optical system, and then photoelectrically converted by the detector into an electrical signal and output as a digital quantity with a predetermined number of bits. However, this number of bits is also determined by the desired gradation for the video.

The scanning and light reception carried out in this manner is carried out using each pixel in the target irradiation field as a processing unit, and this pixel is usually vertically divided by the laser beam.

It is a small rectangular or rectangular area obtained by dividing the irradiation field scanned in the horizontal direction into a predetermined number.

Now, the images corresponding to each wavelength obtained in this way.

That is, target extraction processing is then performed on the multispectral video. As mentioned above, this process develops multiple images on correlated coordinates based on the signal strength of the same pixel of images of each wavelength, and then associates an arbitrary color with the characteristic area of each object on the coordinates to create a color image. It is something to be regenerated. For example, when developing two-wavelength video pixels on two-dimensional correlation coordinates, the horizontal axis represents the signal intensity of wavelength λ1, and the vertical axis represents the signal intensity of wavelength λ2 for pixels at the same position on the screen. Expands according to signal strength. Therefore, if there is no difference between the two wavelength images due to the difference in wavelength, all the image pixels will be lined up on the 456 line on the correlation coordinates. Video pixels that fall outside of the 45° line of the correlation coordinates will have wavelength characteristics that are different from other objects, so this part is artificially given a noticeable color (for example, red) and returned to the original screen. A clear image with no intermediate colors in which characteristic parts are colored differently can be obtained.

Although the above description is based on an example of an active method, it is clear that video processing obtained by a passive method can be basically implemented in substantially the same manner.

For example, in the active method, the intensity of the reflected light differs for each wavelength of the projected light, and the characteristics of the reflected intensity corresponding to each wavelength, so-called spectral reflection characteristics, also differ for each object in the irradiation field.

FIG. 1 is a diagram showing the spectral reflection characteristics of typical natural objects existing in the irradiation field on the ground.

Typical natural objects include pine trees, dead leaves, and sandy soil, and their spectral reflection characteristics are shown in Figure 1, a and a, respectively.
Shown as b and c.

The horizontal axis in FIG. 1 indicates the wavelength of the projected light in nanometers (nm), and the vertical axis indicates the reflectance in units of nm (nanometers). 1st
As can be seen from the figure, the reflectance of each object differs greatly depending on the wavelength of the laser beam projected. Figure 1 takes natural objects as examples, but artificial objects such as buildings and vehicles that are interposed between these natural objects also exhibit unique spectral reflection characteristics.Therefore, they are colored in the same family, which is difficult to distinguish with the naked eye. Discrimination between different types of objects is also possible using such spectral reflection characteristics.

FIG. 2 is a reflection intensity correlation distribution diagram showing an example of a correlation distribution of reflection intensities at two wavelengths.

In Figure 2, the pine tree shown in Figure 1 is used as an example of a reflective object.
This shows the case where dead leaves, sandy soil, etc. are the target.The horizontal axis shows the reflection intensity of one of the two wavelengths projected at the same level, λl, as a reflectance, and the vertical axis shows the reflection intensity of the other wavelength, λ2. is shown in terms of reflectance. In this case λt=500
nm, λ2=800 nm.

The original image by the laser light of these two wavelengths is acquired pixel by pixel, and the position of each pixel on the two original images is determined as one point on this correlation coordinate by the difference in reflection intensity at the two wavelengths. . a' is the reflection intensity correlation area of the pine tree due to two wavelengths in the irradiation field, that is, the laser beam scanning field, bl is the dead leaves, and c/ is the area for the sandy ground. In this way, it is determined at which point on such correlation coordinates all the pixels that make up the image are located.

For example, after artificially coloring pixels distributed in area a' red, pixels distributed in area b' blue, and pixels distributed in area C' green, these two images are reconstructed. Then, the pine part is red,
Dead leaves are colored blue and sandy areas are colored green, making it possible to obtain an image in which the positions of pine trees and dead leaves are clearly distinguished from the sandy area.

Such image processing technology has recently been frequently used as an effective means for extracting a target from a multispectral image obtained by remote sensing.

However, in conventional imaging equipment for the purpose of target extraction of this type, the reflected light for each wavelength is stored in memory for each pixel, and the image processing including the above-mentioned correlation processing is processed by a computer, so it is not possible to do so in real time. It has various disadvantages, such as being unable to process data, making the overall system configuration large, and requiring complicated operation.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks, to provide a video device that can perform video processing in real time, greatly simplifies the system configuration, is easy to operate, and is inexpensive.

The apparatus of the present invention includes means for sequentially scanning and irradiating laser beams of a plurality of wavelengths in correspondence to pixels, means for converting reflected light corresponding to the pixels from the scanned target into an electrical reflection signal, and a means for converting the reflected signal from the scanned target into an electrical reflection signal. Correlation weight extraction means for extracting a weight of the intensity correlation corresponding to the intensity correlation distribution characteristic of the reflectance by wavelength or radiant energy by wavelength for each target based on the intensity correlation, and a weight of the intensity correlation obtained corresponding to the pixel. and means for displaying a target color according to a color specified in advance in accordance with the pixel.

Next, the present invention will be described in detail with reference to the drawings.

FIG. 3 is a block diagram showing one embodiment of the present invention.

The embodiment shown in FIG. 3 is a means for extracting correlation weights for each pixel of input signals obtained for each wavelength when a target is extracted from a multispectral image obtained by remote sensing using two wavelengths of laser light. The receiving circuit that collects reflected light or radiant energy and converts it into an electrical signal, the color display circuit after target extraction, etc. are almost the same as those of conventional video devices of this type.

In Fig. 3, the reflected light obtained while scanning the irradiation field by projecting laser light with two wavelengths λ1 and λ2 of equal level is converted into electrical signals one after another for each pixel and is converted into an electric signal as input signals Sλ1 and Sλ2, respectively. Input terminal 1
01 and 102.

The embodiment shown in FIG. 3 is comprised of level discrimination circuits 1, 2, 3 and 4, a division circuit 5, AND circuits 6 and 7, etc., and is based on the combined operation of these level discrimination circuits and division circuits as described above. The weight extraction of the correlation for each pixel of the two wavelengths of reflected light is carried out as follows, and then AND
Two desired colors are specified through a circuit.

Input signal Sλ2 is sent to level discrimination circuit 1 and level discrimination circuit 3.
and the division circuit 5, and the input signal S
λ1 is a level discrimination circuit 2. The signals are sent to the level discrimination circuit 4 and the division circuit 5, respectively.

The input signals Sλ1 and Sλ2 both correspond to reflected light from the same irradiation field, and the reflected light from the target is also divided into these input signals Sλ! in pixel units. .

Included in Sλ2.

FIG. 4 is an intensity correlation distribution diagram of input signals of two wavelengths in the embodiment of FIG. 3. The embodiment shown in FIG. 3 will be described below with reference to FIG. 4.

In Figure 4, the targets are intensity distribution area A, which is modeled as a rectangle, and intensity distribution area B, which is modeled as a trapezoid.
Assume that there are two shown in . A target on the ground obtained by irradiation with laser beams of two wavelengths is thus converted into an input signal having an intensity distribution region that can be approximated as a rectangle or trapezoid, and is inputted via input terminals 101 and 102.

In Fig. 4, the intensity distribution area A has a strong level of Sλ2, one side is between levels b1 and b2 of Sλ2, and the other side is Sλ2.
It is a rectangular area with a size between levels a3 and 84 of Sλ1, and the intensity distribution area B has a strong level of Sλ1, as shown in FIG. In the range above level b8, the upper base is shown as a trapezoid with a slope a represented by Sλ2/Sλl.

In this embodiment, the intensity distribution area A is artificially colored red, and the intensity distribution area B is colored green, and these intensity distribution areas are shown in the correlation intensity coordinates of FIG. The two goals are colored as follows.

In FIG. 3, when a level discrimination circuit 1 receives an input signal Sλ2, it performs level discrimination on all the signals included in this S, and pixel scans the signal for each pixel that satisfies b,<sλ2<bl. are discriminated in time series order and sent to the AND circuit 6.

Similarly, upon receiving the input signal Sλl, the level discrimination circuit 2 performs level discrimination on all signals included in this Sλl, and discriminately outputs signals for each pixel that satisfy a4(8λ1<a3) in pixel scanning order. This IAND
The signal is sent to circuit 6.

When the AND circuit 6 receives outputs from the level discrimination circuits 1 and 2 at the same time, an AND condition is satisfied and a red designation signal is sent to the output terminal 601. The output signals for each pixel output from the level discrimination circuits 1 and 2 are sent to the AND circuit 6, and the AND circuit 6 outputs a red designation signal only when receiving these two outputs at the same time. This means that a red designation signal is output only when there is human power due to reflected light corresponding to the intensity distribution area A shown in the figure, and this red designation signal is sent to the color display circuit via the output terminal 601 and is sent to the color display circuit through the output terminal 601. will be displayed in red.

On the other hand, regarding the intensity distribution area B, it is colored green by the green designation signal as follows.

The level discrimination circuit 3 receives the input signal Sλ2 and sends out to the AND circuit 7 those signals satisfying the condition Sλ2>b3 from all the signals included in this input signal while discriminating the level of each pixel in the scanning order. This is a conditional process in which the existence range of the intensity distribution area B on the intensity correlation coordinates of FIG. 4 is in a level range larger than b3 for Sλ2.

Next, the level discrimination circuit 4 receives the input signal Sλ1 for each pixel, performs level discrimination on all the signals included in this input signal, and outputs a signal that satisfies the condition a2<Sλthat. This level discrimination is conditional processing for the level range at the bottom of the intensity distribution area B shown in the shape of a trapezoid.

The division circuit 5 provides a condition for determining the upper base of the trapezoidal intensity distribution area B from the origin 0 of the intensity correlation coordinates shown in FIG. 4 to the area specified by the two conditional processes described above. The division Sλz/Sλ1 is performed on the input Sλ1 and Sλ2 for each input, and furthermore, this value is α
Level discrimination is performed only for those that do not exceed A
The signal is sent to the ND circuit 7. Here α=tanθ.

In this way, the three conditional processes that limit the intensity distribution area B are performed, and when the outputs obtained by these three conditional processes are simultaneously applied to the AND circuit 7, the AND condition is satisfied and the AND circuit 7 designates green. Output terminal 6 as a signal
02 and is sent to the °C color display circuit through this output terminal 602, and the intensity region B is displayed in green.

As described above, the weight of the intensity correlation of the two wavelengths of reflected light with respect to the intensity distribution areas A and BK on the intensity correlation coordinate, that is, the degree of intensity of the two wavelengths of reflected light in the intensity distribution areas A and B, is determined by the level discrimination circuit and They can be easily extracted from the original video by an arithmetic circuit including a division circuit, and each color is specified in advance. In this example, intensity distribution area A is specified as red, and intensity distribution area B is specified as green. , the target corresponding to these intensity distribution areas and B can be clearly shown.

The example shown in FIG. 3 targets images obtained by reflected light from laser beams of two wavelengths, and extracts correlation weights of intensity by wavelength for two targets showing the intensity correlation distribution shown in FIG. 4. However, the case where these two targets are colored red and green respectively is taken as an example, but these two wavelengths may be three wavelengths or any number of wavelengths, and the number of wavelengths corresponding to this number of wavelengths may be For a modification such as increasing the number of targets, the number of level discrimination circuits and division circuits and their combinations are appropriately selected in accordance with the intensity level distribution of the target on the intensity correlation coordinates, etc., and these are ANDed.
It is obvious that this can be easily implemented by combining it with a circuit, and the coloring can also be arbitrarily set.

Furthermore, although this example deals with two targets having intensity correlation distributions modeled as shown in FIG. It is obvious that this can be easily implemented using a rectangular or trapezoidal display that includes a rectangle corresponding to the intensity distribution. Furthermore, when the intensity distribution region to be approximated is only a rectangle or a rectangle, the division circuit 5 in FIG. It is possible to extract correlation weights without using .

Furthermore, the original image displayed in color by such a correlation extraction means may be obtained by remote scanning between any two points, such as ground-to-ground or air-to-ground. The embodiment shown in Figure 3 is an example of a case where wavelength-based reflectance is used, but it is clear that it can be implemented in almost the same way when using radiant energy, and all of the above will defeat the purpose of the present invention. It can be easily implemented.

As explained above, according to the present invention, a first-order image is reconstructed by extracting the correlation weight based on the reflection signal corresponding to each pixel, so coloring can be performed in real time, and the image processing apparatus is small and lightweight. This has the effect that it is possible to realize a video device that is easy to operate and can greatly improve video processing efficiency.

[Brief explanation of the drawing]

゛Figure 1 is a spectral reflection characteristic diagram of typical natural objects existing in the irradiation field on the ground, Figure 2 is a reflection intensity correlation distribution diagram at two wavelengths, and Figure 3 is a block diagram showing one embodiment of the present invention. ,
FIG. 4 is an intensity correlation distribution diagram of the two-length input signal in the embodiment of FIG. 1.2, 3.4...Level discrimination circuit, 5...
... Excluded agent Patent attorney Susumu Uchihara (21, 9
Brown 1 Figure 10 20 Reflection intensity of JO4050 liter? closed

Claims (1)

[Claims] Scans laser beams of multiple wavelengths sequentially corresponding to pixels,
means for irradiating; means for converting the reflected light corresponding to each pixel from the scanned target into an electrical reflection signal; and the intensity correlation distribution of the reflectance by wavelength or radiant energy by wavelength for each target based on this reflection signal. Correlation weight extracting means for extracting the weight of the intensity correlation corresponding to the characteristic; means for displaying a target color for each pixel by specifying a color specified in advance corresponding to the weight of the intensity correlation obtained for the pixel. An imaging device comprising: