JPH02304680A - Image processor - Google Patents

Abstract

PURPOSE:To attain accurate reading by reading out image information based upon a compared result with an image between an image outputted when an object is illuminated with light and an image outputted when the object is not illuminated. CONSTITUTION:When a detection pulse is outputted from a stop detector 20, a control device 11 opens a gate 26 to transfer an image picked up by a CCD camera 2 to an image memory 24. The control device CTR 11 closes the gate 26 to driven an infrared-ray irradiating device 3 and then opens a gate 27. A train 1 is irradiated with infrared rays from a device 3 and the CCD camera 2 picks up the image of a portion on which a train number irradiated with infrared rays is written. The image is transferred from the camera 22 to an image memory 25 through the gate 27. After completing the transfer, the CTR 11 closes the gate 27 and opens gates 28, 29. The image data respectively stored in the image memories 24, 25 are applied to a difference image memory 30, which finds out the difference value of lightness between corresponding picture elements in both the images and stores the value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention generally relates to an image processing apparatus, and particularly relates to an image processing apparatus for photographing an object such as an outdoor train.

(Conventional technology) In transportation systems such as railways, diagrams (
When the so-called timetable is disrupted, in which trains are not operating according to the schedule (hereinafter referred to as the "timetable"), it is necessary for train dispatchers, signal handlers, etc. to perform the tasks described below. Become. In other words, as a prerequisite for giving departure commands and route control, train dispatchers, signal handlers, etc., use the telephone or radio to communicate with the station staff at each station and the crew members of each train to determine the train number assigned to each train. By checking and comparing and contrasting this train number with the train number attached to the timetable,
It becomes essential to perform work to confirm the starting station, destination, departure time, train type, etc. of each train.

The above-mentioned work places a heavy burden on the driving dispatcher, the signal handler, and the like. Therefore, as a means to save the labor of the above-mentioned work, train number reading devices have been used in some railways. The outline of this train number reading device is that it consists of a resonator installed on the train that can set a unique frequency for each train number, and an electromagnetic wave generator installed on the ground. Is it possible to read the train number using the fact that the electromagnetic waves generated and reflected from the resonator differ depending on the resonant frequency of the resonator provided for each train? This is how it is supposed to work.

In the above-mentioned train number reading device, it is necessary to provide a resonator and its auxiliary equipment on the train, so the equipment cost becomes very high when the number of trains is large.

Particularly in railways where mutual access is carried out, it is necessary to install the above-mentioned device not only on the company's own vehicles but also on the vehicles of the partner company with which it is connected, which is currently difficult to implement.

Therefore, instead of the above-mentioned train number reading device, a device has been proposed that can read the train number by so-called image processing without installing a special device on the vehicle. Figure 6 shows a device (hereinafter abbreviated as "image processing device") that reads train numbers by using an image processing process without requiring any special device on the vehicle.
This is what is shown.

In Figure 6, CCD camera 2 installed on the ground
images the train number (OIT) of train 1, which is the subject,
When the image 6 of the train number (OIT) shown in FIG. 7 is output to the number reader 4, the number reader 4 reads the train number from the image 6 through the image processing process described above, and Train number information is output. An infrared irradiation device 3 is installed near the COD camera 2, and emits infrared rays (wavelength + 830 low) invisible to the human eye in the direction of travel of the train 1, which is the subject.
It is designed to irradiate.

Note that an infrared filter 5 is attached to the CCD camera 2 so that only infrared light around a wavelength of 830 na+ can be taken in.

FIG. 5 is a block diagram showing the overall functional configuration of the conventional image processing apparatus shown in FIG. 6. In FIG. 5, the train detector 10 is connected to the train 1 (illustrated in FIG. 6).
When it reaches a predetermined position, it outputs a trigger signal. The control device CTRLI starts the control operation when the trigger signal is given from the train detector 10, and controls the CCD camera 2, the infrared irradiation device 3, the image memory 7, and the character reader 8.
It is designed to control the drive of the Infrared irradiation device 3
irradiates a predetermined infrared light under the control of the control device CTRLI. Under the control of the control device CTRII, the CCD camera 2 images the train 1, which is the object illuminated by the infrared light emitted from the infrared irradiation device 3, and stores the resulting 1g image in the image memory 7. Output. The image memory 7 receives and stores image data output from the CCD camera 2 under the control of the control device CTRII, and outputs the stored image data to the character reader 8. The character reader 8 is a control device CT.
Under the control of the RII, the image data output from the image memory 7 is received, and as described above, the train number information is read from the image data through the image processing process and output.

(Problem to be Solved by the Invention) By the way, in the conventional image processing device described above, as is clear from the above-mentioned content, the CCD camera 2 has a wavelength of 8.
Since the infrared filter 5 is installed so that only infrared light around 30n11 can be taken in, theoretically, only light with a wavelength around 830 nm will pass through the infrared filter 5. Therefore, the infrared irradiation device 3
Most of the reflected light from train 1, the subject illuminated by infrared rays, passes through the infrared filter 5, but the image of train 1 created by the sunlight that hits and reflects the train 1, the subject, consists only of light at wavelengths around 830n-. In order to narrow down the image, the CCD camera 2 is
It was assumed that the image of train 1 taken by was hardly affected by sunlight.

However, in reality, the illumination intensity of sunlight is very high, so even if the infrared filter 5 narrows down the intensity, the influence of sunlight cannot be canceled out unless the intensity of the infrared rays emitted from the infrared irradiation device 3 is considerably increased. . Furthermore, since the angle of incidence of sunlight changes from morning to afternoon to evening, the shadows of surrounding buildings may fall on Train 1, and the weather (sunny, cloudy, rainy)
Since the illuminance changes depending on the situation, it is difficult to always capture images with stable image quality. For example, the image 6 shown in FIG. 7 may become the image 16 shown in FIG. 8 due to the shadow of the electric wire. Such an image 16 is C
When the image is output from the CD camera 2, there is a problem in that extremely complicated image processing must be performed in order to read the characters OIT from the image 16.

The present invention has been made in view of the above, and its purpose is to:
By removing noise caused by sunlight from images captured by a CCD camera, it is possible to obtain stable images that are not affected by sunlight, which eliminates the need for complex image processing processes. An object of the present invention is to provide an image processing device that can accurately read image information without any problems.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, an image processing apparatus according to the present invention includes: an imaging means for capturing an image of a subject and outputting an image of the subject; an illumination means for illuminating the subject; a first storage means for receiving and storing an image output from the imaging means when the illumination means is not illuminating the subject; and a first storage means for receiving and storing an image output from the imaging means when the illumination means is illuminating the subject; a second storage means for receiving and storing the output image; and based on a comparison result between the image stored in the first storage means and the image stored in the second storage means. The configuration includes means for reading image information.

(Function) In the above configuration, in order to eliminate disturbances caused by extremely high illuminance light rays such as sunlight, the image of the subject outputted from the imaging means when a predetermined light ray is not irradiated from the illumination means is first used. The first storage means stores an image of the subject output from the imaging means when a predetermined light beam is irradiated toward the subject from the illumination means, and the second storage means stores an image of the subject outputted from the imaging means. Since the image information is read based on the comparison result between the image of the subject stored in the first storage means and the image of the subject stored in the second storage means, the image information is read by the imaging means. Since noise caused by sunlight can be removed from captured images, images with stable image quality that are unaffected by sunlight can be obtained at all times, making it possible to simplify complex image processing processes. It is now possible to accurately read image information without the need for additional information.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the overall functional configuration of an image processing apparatus according to an embodiment of the present invention.

In FIG. 1, the same components as those shown in FIG. 5 are given the same reference numerals.

In FIG. 1, a stop detector 20 detects when a train has stopped at a proper position within a station.

In this embodiment, the stop detector 20 includes a light source 35, a reflector 36, and an optical switch 37 shown in FIG. 3, and a timer and timer drive stop detection means (none of which are shown). There is. The light source 35 and the light switch 37 are installed on a platform 38 several meters before the last regular stopping position of the train 1 in the station yard in the train's traveling direction. A reflector plate 36 connects the light source 3 across the line.
5. It is installed at a position facing the optical switch 37.

The timer (not shown) starts driving when the logic level of the output signal of the optical switch 37 changes from OFF to ON.

The timer drive stop detection means (not shown) is configured to detect that the timer has stopped after being driven for a predetermined period of time and output a stop detection pulse. The stop detector 20 detects that when the train 1 does not block the space between the light source 35 and the forward switch 37 and the reflector 36, the light irradiated from the optical FAB 5 is reflected by the reflector 36 and the light is switched to the light switch 3.
7 and the optical switch 37 is turned on, the timer and timer drive stop+1 detection means directly output the logic level "ON" signal without any time delay. Further, when the stop detector 20 blocks the light between the train 1, the light source 35 and the light switch 37, and the reflector 36, the stop detector 20 emits light l! 7. The light emitted from 35 is the light switch 3
7 has not been reached, the optical switch 37 is turned OFF, and the timer and timer drive stop detection means directly output a logic level 'OFF' signal without any time delay.

When the stop detection pulse is output from the stop detector 20, the control device CTRII determines that the Guri Junior High School 1 has stopped at a regular stop position in the station premises, starts control operations, starts the CCD camera 2, The driving of the infrared irradiation device 3, gates 26, 27, 28° 29, image memory 124, image memory n25, and differential image memory 30 is controlled. The infrared irradiation device 3 is a control device CTRI.
A predetermined infrared light is irradiated under the control of I. The CCD camera 2 is mounted on the platform 38, etc. in the station premises so that when the train 1 stops at the correct position in the station premises, the part where the train number (OIT) of the first car of the train 1 is written is within the imaging area. are installed at appropriate locations. Note that the CCD
When installing the camera 2, the imaging screen should be set so that the part where the train number (OIT) is written will be within the imaging area even if the train 1 stops at a position slightly deviated from the normal position in the station premises. A margin shall be allowed for. C
Under the control of the control device CTRII, the CD camera 2 captures an image of the train 1 when no infrared light is irradiated from the infrared irradiation device 3, and also captures the captured image of the train 1 using the CCD camera 2. The brightness value of each pixel (hereinafter simply referred to as "pixel") corresponding to one CCD is stored as an analog quantity.

When the gate 26 is opened by the control device CTRII, the CCD camera 2 outputs the brightness value of each pixel of the image of the train 1 stored as an analog value through the gate 26 to the A/D converter 32 shown in FIG. do. The A/D converter 32 converts the analog value into a digital value, and then outputs the digital value to the image memory 124. The image memory 124 stores brightness value data for each pixel of the image of the train 1, which has been converted into a digital value by the A/D converter 32, for each pixel. Here, the brightness value data for each pixel of the image of the train 1 converted into digital values by the A/D converter 32 is stored in the image memory 124 in a manner as shown in FIG. That is, one pixel 33 is composed of 8 bits,
The brightness of the pixel 33 is converted into an 8-bit digital quantity and stored in the image memory 124.

Further, under the control of the control device CTR11, the CCD camera 2 captures an image of the train 1 while being irradiated with infrared light from the infrared irradiation device 3, and also captures an image of the train 1 for each pixel of the captured image of the train 1. The brightness value of is stored as an analog quantity. When the gate 27 is opened by the control device CTRII, the CCD camera 2 detects the train 1 stored as an analog value.
The brightness value for each pixel of the image is output through a gate 27 to an A/D converter similar to the A/D converter 32 shown in FIG. Like the A/D converter 32, this A/D converter converts the analog value into a digital value and then outputs it to the image memory 25.

The image memory [25 is also configured in the same manner as the image memory 124, and stores brightness value data for each pixel of the image of the train 1 converted into digital values by the A/D converter. The manner in which the image memory n25 stores the brightness value data for each pixel of the image of the train 1 converted into digital values by the A/D converter is the same as described above.

When the gate 28 is opened by the control device CTRII, the image memory I24 outputs the pixel-by-pixel brightness value data of the image of the train 1 stored until then to the differential image memory 30 through the gate 28.

Similarly, when the gate 29 of the image memory 25 is opened by the control device CTR11, the pixel-by-pixel brightness value data of the image of the train 1 that has been stored until then is outputted to the differential image memory 30 through the gate 29.

Under the control of the control device CTRII, the differential image memory 30 stores the brightness value data for each pixel of the image of the train l formed only by sunlight output from the image memory 124 through the gate 28 and the image memory lI2 through the gate 29.
Find the difference in brightness for each corresponding pixel between the column formed by the superimposition of sunlight and infrared light output from 5+ and the brightness value data for each pixel of the image of ■. The difference values of all the pixels forming the image are stored in the order of +1 for each pixel. At the same time, the difference image memory 30 stores the difference values of brightness of all the pixels stored in each pixel unit.
Output to character reader 8.

The character reader 8 performs image processing upon receiving the brightness difference value data of all pixels stored in each pixel unit output from the difference image memory 30, and processes the data by passing through this image processing process. Train number (OIT)
) is read and a code corresponding to the read train number (OIT) is output.

Next, the control operation of the above configuration will be explained.

When the train 1 enters the station premises, the light entering the optical switch 37 is blocked and the optical switch 37 is temporarily turned OFF. As a result, the logic level of the output signal from the optical switch 37 changes as shown in FIG. ON at the time indicated by code 39 of waveform A
It becomes OFF.

Thereafter, just before the train 1 decelerates and stops at the correct position inside the station, the tail end of the train 1 passes through the section where the light source 35, the light switch 37, and the reflector 36 are facing each other, and the light source 35 illuminates the train 1. The light is reflected by the reflector 36 and enters the optical switch 37 again, so the optical switch 3
7 is turned ON.

Therefore, the logic level of the output signal from the optical switch 37 changes from OFF to ON at the time point 40 of waveform A in FIG. When the optical switch 37 changes from OFF to ON, the above-mentioned timer starts driving (the time indicated by reference numeral 41 in waveform B in FIG. 4), and stops driving after a certain period of time (10 seconds in this embodiment) has elapsed. (Symbol 4 of waveform B in Figure 4)
2). When the timer stops driving, the timer drive stop detection means outputs a stop detection pulse as shown by waveform C in FIG. 4. That is, the train 1 stops at the regular stopping position in the station premises. 10 seconds after the entire train 1 passes through the opposing section between the light source 35, the light switch 37, and the reflector 36, the train stops at the regular stop position in the station. It is assumed that the vehicle is stopped at the parking position. When viewed in this way, even if train 1 has not actually stopped, it is on the verge of stopping, so there is no problem with the CCD camera 2 capturing an image of the part where the train number (OIT) of train 1 is written. do not have. When the timer drive stop detection means, that is, the stop detector 20 outputs a stop detection pulse as shown in waveform C in FIG. The data is transferred to the memory 124. When the transfer of the captured image by the CCD camera 2 to the image memory 124 is completed, the control device CTRII closes the gate 26, drives the infrared irradiation device 3, and opens the gate 27. When the infrared irradiation device 3 starts operating, the train 1 is irradiated with infrared rays from the infrared irradiation device 3, so that the CCD camera 2 records the train number (OIT) irradiated with the infrared rays along with sunlight. An image of the site will be taken. This image is transferred from the CCD camera 2 to the image memory II 25 through the gate 27. When the transfer of the captured image by the CCD camera 2 to the image memory 1125 is completed, the control device CTRII closes the gate 27 and opens the gates 28 and 29.

By opening the gates 28 and 29, the image data stored in the image memory I24 and the image memory port 25, respectively, is given to the differential image memory 30, and the differential image memory 30 stores the correspondence between the two images as described above. The difference value in brightness between the pixels is calculated and stored.

Here, noise such as shadows and reflections formed by sunlight irradiation is of course not only caused by the image captured by the CCD camera 2 when only sunlight is irradiated, but also by the superimposition of sunlight and infrared light. It also exists in the image taken by the CCD camera 2 when it is illuminated by the target. Therefore, as mentioned above, there is a difference between the image captured by the CCD camera 2 when sunlight and infrared light are irradiated in a superimposed manner and the image captured by the CCD camera 2 when only sunlight is irradiated. , if we take the difference in brightness values between corresponding pixels, we can find that when only sunlight is irradiated from the image component captured by the CCD camera 2 when sunlight and infrared light are irradiated in a superimposed manner. CC of
One component of the image taken by the D camera 2 is canceled, and only the image formed by irradiation with infrared rays remains. In other words, it is possible to obtain an image equivalent to that obtained by irradiating only infrared rays in a pitch-dark place where there is no sunlight, and therefore an image with stable image quality that is always free from the influence of sunlight can be obtained. It will be. The character reader 8 searches for characters from the image thus obtained, reads the found characters using a general character discrimination method, and outputs a code corresponding to the read characters.

As explained above, according to an embodiment according to the present invention,
It is possible to obtain images with negligible effects of sunlight using infrared illumination, which is invisible to the human eye, so it eliminates changes in subject images caused by sunlight, which are always a problem when processing images of outdoor subjects. To counter the brightness of sunlight, which does not need to be taken into account and which cannot be overcome by using artificial lighting, it is possible to reduce the brightness of passengers such as drivers by using things like camera flashes. This eliminates problems such as nuisance and nuisance to people in the vicinity, and it also makes image processing easier because images with stable image quality can always be captured.

Although the image processing device according to this embodiment has been described as being used to read train numbers, the image processing device according to this embodiment can be used to capture any object as long as it is stationary. By using , image processing can be easily performed.

For example, when reading the number of a bicycle stopped at a gate, substantially the same effect as reading a train number can be obtained.

Furthermore, if the image processing device according to this embodiment is applied only to a completely stopped subject, the stop+detection pulses output from the stop detector 20 and the stop detector 20 are not required.

〔Effect of the invention〕

As explained above, according to the present invention, an image output from the imaging means when the illumination means is illuminating the subject, and an image output from the imaging means when the illumination means is not illuminating the subject. Since we decided to read the image information based on the comparison result between It is possible to provide an image processing device that can obtain high-quality images and thereby accurately read image information without requiring a complicated image processing process.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an overall functional configuration of an image processing device according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a partial functional configuration of an image processing device according to an embodiment of the present invention. FIG. 3 is a schematic diagram of a station premises in which an image processing device according to an embodiment of the present invention is used, and FIG.
FIG. 5 is a timing chart showing the operation of a stop detector included in an image processing device according to an embodiment of the present invention, and FIG. 6 is a block diagram showing the overall functional configuration of an image processing device according to the prior art. is an explanatory diagram showing the relationship between an image processing device according to the prior art and a train, and FIGS. 7 and 8 are diagrams showing images in which train numbers are recorded, captured by the image processing device according to the prior art. It is. 1... Train, 2... CCD camera. 3... Infrared irradiation device, 8... Character reader, 11... Control device C
T.R. 24... Image memory 1125... Image memory ■, 3
0...Difference image memory. Applicant's agent Mr. Sato Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Scope of Claims] 1. Imaging means for capturing an image of a subject and outputting an image of the subject, illumination means for illuminating the subject, and lighting from the imaging means when the illumination means is not illuminating the subject a first storage means for receiving and storing the output image;
a second storage means for receiving and storing an image output from the imaging means when the illumination means is illuminating the subject; and a second storage means for receiving and storing an image output from the imaging means when the lighting means is illuminating the subject; An image processing apparatus comprising: means for reading image information based on a comparison result with an image stored in a storage means. 2. The image processing apparatus according to claim 1, wherein the illumination means is an infrared irradiation device.