JPS60162970A - Image tracking device - Google Patents

Abstract

PURPOSE:To eliminate the influence to be inflicted on an artificial light source and to improve the precision and reliability of an optical tracking device by picking up images of the same visual field in two wavelength ranges by utilizing the difference in spectrum distribution between infrared-ray radiations from a target and an artificial light beam, and performing signal processing. CONSTITUTION:A dichroic mirror 12 has transmissivity and reflectivity and near infrared light and far infrared light are demultiplexed to form infrared images in respective wavelength ranges on two infrared-ray solid-state image pickup elements 13a and 13b. Then, a comparator 15 compares picture element outputs which are amplified by amplifiers 14a and 14b and corresponds to the elements 13a and 13b and outputs a binary-coded picture element signal 16. Then, the signal 16 is inputted to a peak point detecting circuit 19 through a horizontal compressed value arithmetic circuit 17 to obtain a vertical tracking position signal 5 by the circuit 19. A gate position signal 21 from a gate setting circuit 20 is inputted to a vertical compressed value arithmetic circuit 22 together with the signal 16 and the vertical compressed value signal 23 outputted by it is processed by gravity center arithmetic 24 to obtain a horizontal tracking position signal 6. Consequently, the influence of the artificial light source is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an infrared image tracking device that is capable of accurately tracking a target without being distracted by pseudo light sources, background noise, etc.

[Prior art]

In conventional infrared image tracking devices, the tracking point of a target is determined by capturing an infrared image of the target with an infrared imaging device and calculating the center of gravity of the obtained video signal.

FIG. 1 is a diagram showing an example of the configuration of a conventional Yuzu device, in which (1) is an imaging optical system, (21 is an infrared imaging device, and (21 is an infrared imaging device).
3) is a video signal, (4) is a center of gravity calculation circuit, (5) is a vertical tracking position signal, and (6) is a horizontal tracking position signal.

In FIG. 1, the infrared imaging device (2) has an imaging optical system f
An infrared image of the target formed by il is captured, and an image signal (3) is output to the center of gravity calculation circuit (4). The center of gravity point calculation circuit (41) calculates the offshore heart position li1 coordinates of the target, and calculates the position of the target in the 1 m vertical direction [proportional to the vertical tracking position F (5), and the position proportional to the horizontal coordinate position. Horizontal direction j!i+tail position capture 1 signal (6) is output.

Figure 2 shows an example of an infrared image captured by an infrared imaging device, in which (71 is the screen, (81 is the target, (9) is a pseudo light source with a spectral distribution in the near-infrared region, and (9) is a pseudo light source with a spectral distribution in the near-infrared region. is an artificial light source with a spectral distribution in the far and mid-infrared regions, 0υ
is the center of gravity.

In Fig. 2, the target (81
0 screen (71 is a pseudo light source with a spectral distribution in the near-infrared region (9) (e.g. sunlight reflected on the sea surface) or an artificial pseudo light source with a spectral distribution in the far and mid-infrared regions) ( For example, when an artificial light source (such as a lever) enters, since these pseudo light sources generally have surface brightness, the center Aflll of both the target and the pseudo light source is calculated, and as a result, the tracking position deviates from the target. There were 9 flaws. Horizontal direction 1 like target +81 in special VL figure 2
c If the target is long and short in the vertical direction, even if the deviation of the vertical position of the center of gravity is small, it will cause the eye TM to miss, resulting in I/C. This is a devastating drawback.

[Summary of the invention]

This invention aims and pseudo! By taking advantage of the difference in the spectral distribution of the infrared light emitted by Eido, the same field of view is captured in two wavelength regions, and signal processing is performed to remove the influence of a pseudo light source with a spectral distribution in the near-infrared region. After the signal is obtained, this video signal is added and compressed in the horizontal direction, and the compression value reaches its maximum value.

The vertical coordinates of the target tracking point are taken as the center, and the minute pixel width is adjusted in the vertical direction around this point.The horizontal direction VC is provided with a gate having a wide range of pixel widths, and the video signal within this gate is added and compressed in the vertical direction. By setting the center of gravity of the compression value to the horizontal coordinates of the target tracking point, the influence of pseudo light sources with spectral distribution in the far and mid-infrared regions is removed, and as a result, almost all pseudo light sources can be removed. It provides a complete means of eliminating shadow exposure and eliminating the drawbacks of the prior art. below.

This invention will be explained in detail using figures.

[Embodiments of the invention]

FIG. 3 shows the configuration of one embodiment of the present invention, which includes a Q2+tri tychroic mirror, (+3a)
is the first infrared solid-state image sensor, (+3b) is the second infrared solid-state image sensor, (14a) and (+4b) are each an amplifier, (151 comparator, Qlil is a bivalent pixel signal, fI force is horizontal direction IEIE Tsumugi calculation circuit, +181
is the horizontal compression value signal, a! 1-digit peak point detection circuit, (
(a) is a gate setting circuit; C7+lij is a gate position signal or vertical compression value l# calculating circuit; (i) is a vertical compression value signal; C41 is a center of gravity calculation circuit.

FIG. 4 is a diagram showing an example of the spectral distribution of the target and the pseudo light source, in which 051 is the spectrum of sunlight, 051 is the spectrum of the artificial pseudo light source, and 07J is the spectrum of the target.

FIG. 5 shows an example of the spectral transmittance and reflectance of a dichroic mirror (a) and (2) Vi transmittance.

(2) indicates reflectance.

FIG. 6 shows a binarized pixel signal (I) obtained from comparator 01 when the video shown in FIG.
li) shows an example of the gate setting in the present invention, and C1) shows the gate for determining the horizontal tracking position;
(11 is the tracking small.

In FIG. 3, the dichroic mirror 04 is.

Since the transmittance and reflectance shown in FIG. 5 are obtained, the first infrared solid-state image sensor (13a) and the second infrared solid-state image sensor (
131)), near-infrared light with a wavelength of 1 to 2.5 μm and far-infrared light with a wavelength of 9 to 10.5 μm are branched, and an infrared image in each wavelength range is formed. It turns out.

By the way, in general, the spectral sensitivity of an infrared solid-state image sensor is not constant, so in order to correct this, the amplifier (14a) and (+) are used. It is assumed that the output of the amplifier (14a) for the same intensity and the output of the amplifier (14b) for the incidence of far-infrared light of the same intensity are adjusted to be approximately equal.

At this time, as is clear from the spectral distribution in FIG. 4, the output of the amplifier (14a) is always increased for the target +81 pixel with spectrum C271 and the artificial pseudo light m and sky pixel with spectrum @. A pseudo light source (9) that is smaller than the output of the width filter (14b) and has a spectrum of 3+1.
It can be seen that the opposite is true for the pixel.

The comparator shown in FIG. 3 is the output of the amplifier (14b), which is greater than the preset threshold.

It is configured to output '1' only when the output of the amplifier (14a) is smaller than the output of the amplifier (141), and to output 'OI' otherwise. In (1 smoothed 21 normalized pixel signal 06), as shown in Figure 6, the influence of a pseudo light source (9) with a spectral distribution in the near-infrared region, such as sunlight reflected on the sea surface, is removed. .

This binarized pixel signal (161'f: P
(1゜j) (where 1 is the horizontal coordinate, j is the vertical coordinate, 1<i×M, 1×j×N, M is the horizontal width of the image, and the vertical width of the image is If h (j) is the horizontal compression value signal (11) obtained by the horizontal compression value calculation circuit 01, then the relationship of equation (1) holds true.

h(jn = Σ　P('+　j)　...(1 in 11 On the other hand, in the binarized pixel signal 061 shown in FIG.

Artificial pseudo light source O with spectral distribution in the far and mid-infrared regions
Q is not removed. This artificial artificial light source OI generally has an extremely small width in the horizontal direction compared to a target +8+ (for example, a ship) that is long in the horizontal direction and short in the vertical direction, as shown in FIG. ).This peak value is much larger than 11 of h (j) due to the normal artificial artificial light source 00. If the value of j when (j) takes the peak value is detected, a very accurate vertical tracking position signal (5) can be obtained.
It will be done. That is, the influence of the artificial artificial light maI on the vertical coordinates of the tracking point is almost completely eliminated.

The cell setting circuit (a) in FIG. 3 sets a cell whose vertical width is minute pixels and horizontal width is a wide range of pixels, centering on the vertical coordinates of the tracking point obtained in this way. . An example of this is shown in the horizontal direction tracking position determining gate cn in FIG. The gate position signal CI++ set by the gate setting circuit in FIG. )
When e v (t), the relationship of Equation 21 holds true.

However, the value of j when L: h (, H) takes the peak value 2n+1: Vertical gate width ■The coordinate G of the center of gravity in (1) is calculated by the center of gravity calculation circuit Qi (1), as shown in equation (3). is subtracted from

By letting G be the horizontal coordinate of the tracking point, a horizontal tracking position signal (6) is obtained. The influence of the artificial pseudo light source 00) and other background noise on the horizontal coordinates of the tracking point can be minimized by setting the horizontal tracking position signal chart with n sufficiently small.

〔Effect of the invention〕

As described above, the present invention greatly reduces the effects of pseudo light sources and background noise, and allows the target tracking point to be accurately determined through relatively simple image signal processing, making it possible to use optical tracking devices. This can greatly contribute to improving accuracy and reliability.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a conventional image tracking device. FIG. 2 is a diagram showing an example of an infrared image imaged by an infrared imaging device, FIG. 3 is a diagram showing the configuration of an embodiment of the present invention, and FIG. 4 is a diagram showing a target and a pseudo optical vision. FIG. 5 is a diagram showing an example of the spectral distribution of . FIG. 6 is a diagram showing an example of the spectral transmittance and reflectance of a dichroic mirror, and FIG.
Rike dichroic mirror, 09 comparator. aη is a horizontal compression value calculation circuit, a C2fj gate setting circuit, and a gate for a horizontal tracking position signal. Note that in FIG. 9, the same or equivalent 85 minutes are indicated by the same reference numerals. Agent Masu Oiwa Figure 1 Figure 2 Figure 4 @ 5 Figure 12Δ45678910 II Figure 6

Claims (1)

[Claims] An image tracking device including an imaging optical system, an infrared body image sensor having sensitivity in the infrared region, and a video signal processing means, which is placed in an imaging optical path and captures incoming light. and a demultiplexing means for separating light into near-infrared light and far-infrared light. A first infrared solid-state image sensor installed on a two-layer near-infrared light imaging surface that has been demultiplexed, and a second infrared solid-state image sensor that is installed on the far-infrared light imaging surface that has been demultiplexed. Binarization I[ i11 element signal tone obtaining means, and means for detecting the vertical coordinates of the point at which the compressed value obtained by adding 8E sets of the binarized image purple signals in the horizontal direction is the maximum. , minute 1ij in the vertical direction
means for providing a gate having a pixel width i and a wide pixel width in the horizontal direction; and means for calculating the center of gravity of the compressed value obtained by compressing the pixel signal in the gate in the vertical direction. That is the % emperor. Sen 1 image tracking device.