JPS58182784A - Optical information reader - Google Patents

Abstract

PURPOSE:To read accurately the information on a recording medium, by selecting either one of two different types of light sources in accordance with the type of the drop-out color printed on a recording medium as well as the type of the information recording means. CONSTITUTION:Two types of light sources are provided to irradiate an area of a recording medium 5 where the information is written. One of these two light sources is equal to a pink color fluorescent lamp 1 that has the peak of energy with wavelengths 610-620nm; and the other light source is equal to a near infrared fluorescent lamp 2 that has the peak of energy with wavelengths 740- 750nm. These two light sources are selectively used. Thus the reflected light on the medium 5 is made incident to a photoelectric transducer 8 via a reflecting mirror 6 and an image forming lens 7.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical information reading device, and more particularly to a light source that applies illumination light for reading information to an information written portion of a medium when reading information.

This type of device illuminates the information writing area of the recording medium with a light beam from a light source, makes the reflected light enter a photoelectric conversion element, and reads the written information by converting the reflected light into an electrical signal. I am doing shi. On the recording medium handled by this type of device, as shown in Fig. 1, there is a frame and an item U for specifying the information writing position and information content.
etc. are printed in a color called a dropout color that provides a sufficiently low contrast to the background color (color of the paper surface of the medium, etc.) at the wavelength of the irradiation light used for photoelectric conversion. Information such as characters read by the device is generally written in this frame 1 by handwriting or by printing using a printer device in a color that has a sufficiently high contrast with the background color.

The contrast between the dropout color and the color of information characters and the like with respect to the background color varies depending on the wavelength of the irradiated light. In other words, by using illumination light with a certain wavelength, the colors of the dropout colors and information characters etc. are limited to obtain the contrast described above. To give an example of this, if near-infrared radiation light with a wavelength of 750 to 75 Qnm is used, information characters etc. will be limited to those written with a black pencil, etc., and if written with a black ballpoint pen, the information will be difficult to read. cannot be performed reliably.

Conventionally, this type of device uses a single light source that emits irradiation light with a wavelength suitable for the characteristics of the dropout color printed on the media being handled, the color of the information characters written, or the type of writing instrument. Was. Therefore, it was not possible to read information from the recording medium using a dropout collar other than the specified one, a writing instrument, or the like.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an optical information reading device capable of reading information from recording media using various dropout colors and various information writing means.

According to the present invention, there is provided a plurality of types of light sources having spectral energy at different wavelengths and means for selecting one of them, and information is written on a recording medium using irradiation light from the selected light source. An optical information reading device is obtained which is characterized in that it reads .

Next, refer to Figure 2, which shows the spectral sensitivity characteristic diagram of the optical system consisting of the light source and photoelectric conversion element (COD) of the reading device, and the spectral reflection characteristic diagram of the dropout color and information writing means printed on the recording medium. The present invention will now be described in detail.

As light source A, a pink fluorescent lamp with a peak of light energy at a wavelength of 610 to 620 nm, as light source B,
When using a near-infrared luminescence lamp with an energy peak at a wavelength of 740 to 750 nm, the overall spectral sensitivity characteristics exhibited by these two light sources and the photoelectric conversion element (COD) are as follows.
The visible optical system IA has a peak at 610-620 nm, and the near-infrared optical system IB has a peak at 740-750 nm.

On the other hand, as dropout colors and information writing means such as character frames printed or written on a recording medium, here we use spectral spectroscopy when using blue and orange dropout colors and black pencil and black ballpoint pen information writing means. Let's examine the reflection characteristics. The spectral reflection characteristic ID of the blue dropout color has one reflectance peak near the wavelength of 45 Qnm, shows a decrease in reflectance until about 55 Onm, and then increases again, and shows a high reflectance at about 650 nm or more. The spectral reflection characteristic 2D of the orange dropout color shows low reflectance at wavelengths of 600 nm or less, and high reflectance at wavelengths above 600 nm. In addition, the spectral reflection characteristic IB of a black pencil always shows a low reflectance at each wavelength, and the reflection characteristic of a black ballpoint pen is at wavelength 60.
The emissivity is low below 0 nm, and continues to increase up to 900 nm, and above 900 nm, the emissivity shows a high value that is almost constant over each wavelength.

Using this characteristic diagram, we will examine the contrast of each dropout color and each information writing means in an optical system having the two types of spectral sensitivity characteristics described above. Contrast P, C05 of each dropout color and the target point of each information means with respect to the background color (Print Contrast
Signal) is the spectral sensitivity characteristic S(λ) of the optical system,
It is expressed as follows using the spectral sensitivity characteristic rw(λ) of the white paper portion (background color) and the spectral reflection characteristic γ, (λ) of the target point.

=5- where [λ1. λ, ] is theoretically [0, oo), but it is approximated by the wavelength distribution range of the overall spectral sensitivity characteristic depending on the light source used. In other words, in the case of visible optical system lA, C
500,780). Furthermore, since the spectral reflection characteristic W of the blank paper portion is almost constant, if we set γW(λ)=K (constant), then equation (1) becomes as follows.

When expressing the contrast value using equation (2), the contrast value of the dropout color is 0.15 or less,
The contrast value of the information writing means needs to be 06 or more.

First, when the spectral sensitivity characteristics of the near-infrared optical system are estimated for each contrast value by two people, the reflection characteristics ID and 2D of the dropout color are both [λ1. Range 6 of λ,] is a concave circle and has an almost constant value (K, = 80%). Therefore (2
) formula becomes further. By substituting =85 (%) and =80 (%) into the above equation, P, C, B = 0.06.It can be seen that both are suitable as dropout colors in this optical system. The reflection characteristics IB of a black pencil as a means of writing information are approximately constant values (K,
= 1o%). Therefore, the contrast is K as before.

p, C, S = 1--z, substituting = lO (%) into 9% = 85%, and get P,
C, S=0.88 is obtained. P, C, S = 0.8
8) From 0.6, it can be seen that a black pencil is suitable as a means of writing information in this optical system. On the other hand, considering the reflection characteristics 2B of a black ballpoint pen, γ parameter λ) is λ=
The reflectance gradually increases from around 600 nm and shows a fairly high reflectance (30 to 50%) in the near-infrared range. Therefore (2
), the numerators 1□S(λ)γ and (λ)dλ of the subtraction terms in λ2 have considerably large values, so the contrast value becomes relatively low.

That is, it can be seen that a black ballpoint pen is not suitable as an information writing means in this optical system.

Next, consider each contrast value in the spectral sensitivity characteristic lA in the visible range optical system.The reflection characteristic 2D of the dropout color in the 0-year-old range shows a low reflectance up to around λ = 550 nm, but at λ = 580 nm. Since #1 has a constant high reflectance (approximately 80%) when exceeding 1? S(λJr
p(λ)dri41? stλ)dλ is 1
1 larger value, and therefore the contrast value becomes lower. Considering that the reflection characteristic ID of the blue dropout color exhibits a small reflectance near λ = 610 to 62 Qnm, where the spectral sensitivity characteristic IA reaches its peak value, the subtraction term becomes a small value, and the contrast value becomes quite large. It gets expensive. That is, it can be seen that in the visible range optical system, orange colors can be used as the dropout color, but blue cannot be used.

Since the reflection characteristics IB of a black pencil used as an information writing means are the same as those in the near-infrared region, a high contrast of P, C, and S=0.88 can be obtained. The reflection characteristic 2B of the black ballpoint pen gradually increases near λ = 600 nm and shows high reflectance in the near-infrared region, but considering that the spectral sensitivity characteristics of this optical system are sufficiently low at λ = 700 to 800 nm. When combined, the subtraction term becomes sufficiently small, resulting in high contrast. That is, it can be seen that in the visible range optical system, either information writing means can be used.

Now, in an optical information reading device, it is desirable to be able to use various dropout colors and use various information writing means such as a pencil, a ballpoint pen, and a felt-tip pen. As a dropout color, colors that exhibit low reflectance in visible range optical systems and high reflectance in near-infrared optical systems, such as the reflection characteristic ID of the blue dropout color shown as an example, include purple, There are many colors such as green and brown, but the color that shows high reflectance in both optical systems, that is, the wavelength 550.
It has spectral reflection characteristics with a sharp rise around ~600 nm,
Moreover, colors that give a strong sense of contrast to the human eye,
Limited to orange and red colors. Furthermore, as a means for writing information, a black pencil is a writing instrument that exhibits low reflectance in both optical systems.

It is limited to ballpoint pens for OCR, and commercially available black ballpoint pens and black felt-tip pens exhibit high reflectance in near-infrared optical systems as shown in spectral reflection characteristics 2B in FIG.

From the above, it is clear that devices that read information using optical systems in the visible range, that is, devices that use a lamp or the like with an energy peak in the range of 610 to 620 nm as a light source,
Dropout color is limited to on-register and red. In addition, for devices that perform information reading using a near-infrared optical system, that is, devices that use a lamp with an energy peak in the range of 740 to 75 Qnm as a light source, the means for writing information is limited to a black pencil or a ballpoint pen for OCR. Next, with reference to FIG. 3 showing one embodiment of the present invention, the present invention will be explained in detail with reference to FIG. There are two types of light sources that irradiate the information section.
One is a pink changing light lamp 1 that has an energy peak at a wavelength of 610 to 620 nm, and the other has a wavelength of 740 to 750 nm.
This is a near-infrared wall lamp 2 having an energy peak at nm. Two types of fluorescent lamps 1 and 2 are connected to high frequency lighting devices 3 and 4, respectively. The high-frequency lighting devices 3 and 4 operate when the selection signal S is obtained by switching the switch SW, and turn on the connected fluorescent lamps.

The irradiated light emitted from the light source 1 or 2 is transmitted to the recording medium 5.
A part of the reflected light is changed in its optical path by a reflecting mirror 6 and enters an imaging lens 7. The image focused by the lens 7 provides optical information to a photoelectric conversion element 8, such as a CCD, placed at a certain distance from the lens 7. The reflected light transmitted in this way conveys various contrast changes with respect to the white paper surface depending on the written information.p1
The photoelectric conversion element obtains this information and converts the written information 9 into an electrical signal. Therefore, the device can determine the content of the written t* information based on this electrical signal.

The information reading device having the optical system mechanism according to the present invention can use various dropout colors or various information writing means on the recording medium. That is, if you want to use various dropout colors on the recording medium, limit the information writing means to black pencils and ballpoint pens for OCR, and use the near-infrared region as the optical system for bladder removal.
That is, select the high frequency lighting device 4 by the switch SW,
Information can be read by turning on the near-infrared wall light 2. Also, if you want to use a variety of information writing tools, such as writing instruments, change the dropout color to orange,
Limited to red colors, use a visible range optical system as the optical system, that is, select the high frequency lamp 3, and select the color fluorescent lamp l of the bottle.
The information can be read by lighting up.

As explained above, the present invention provides optical information by selecting one of two types of light sources according to the type of dropout color printed on the recording medium and the type of information writing means. The reading device has the advantage of being able to read information from recording media using various dropout colors and various information writing means with a set of optical system mechanisms, and is of great practical value.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a recording medium handled by an optical information reading device, FIG. 2 is a spectral sensitivity characteristic diagram and a spectral reflection characteristic diagram illustrating the principle of the present invention, and FIG. 3 is a diagram showing one example of the present invention. 0 which is a schematic diagram of the optical system mechanism of the optical information reading device showing an example. ...Recording medium, 6...Reflection mirror 2-17...Imaging lens, 8...Photoelectric conversion element. =13-

Claims (1)

[Claims] comprising a plurality of types of light sources that emit irradiation light of different wavelengths, and means for selecting one of the plurality of types of light sources to emit light,
Information tl written on the recording medium by applying irradiation light onto the recording medium from the selected one light source.
- An optical information reading device characterized by reading.