JPS5834532Y2 - optical character reader - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an optical character reading device for reading, for example, postal codes and the like.

Conventionally, automatic postal code reading devices that read the postal code written in the red frame within a letter have performed the reading as shown in FIGS. 1 to 3.

Figure 1 shows an example of a letter. 1 is a letter, 2 is a red postal code entry frame (preprinted in this letter 1) (
(hereinafter abbreviated as red frame 2), "100" is the postal code written in this red frame.

FIG. 2 schematically shows the apparatus for reading the postal code, in which light from an irradiation lamp 11 is irradiated onto the letter 1 through a condensing lens 12.

The reflected light reflected by this letter 1 is reflected by the reflection mirror 1.
3 and enters the dichroic mirror 14.

The dichroic mirror 14 separates the reflected light from the reflecting mirror 13 into two systems, and each of the separated lights is imaged onto image sensors 16a, 16b via corresponding condenser lenses 15a, 15b.

The characteristics of the dichroic mirror 14 are red reflective, and therefore light in the red wavelength region is obtained on the image sensor 16b side, and visible light excluding red wavelengths is obtained on the image sensor 16a side.

That is, when the postal code of letter 1 as shown in FIG. 1 is read.

From the image sensor 16a, a red frame 2 is detected as shown in FIG. 3a.
A signal containing only characters (hereinafter referred to as a character signal) with the characters removed is output, and a red frame signal with characters (hereinafter referred to as a frame signal) is output from the image sensor 16b as shown in FIG.

These character signals and frame signals are then sent to a logic circuit (not shown) for identification.

However, as can be seen from the configuration shown in Figure 2, the conventional reading device uses a dichroic mirror to read two parts, one on the character side and one on the frame side.
Particularly when the 1-bit aperture of the image sensor is very small, such as several microns, a slight deviation in the lens system will affect the registration of the two images on the character side and the frame side.

For this reason, the character side. Each lens system on the frame side requires a mechanism for fine adjustment.

Further, as is clear from FIG. 2, image sensors are required on each of the character side and the frame side, which poses a problem in that this type of photoelectric conversion device becomes extremely expensive.

This idea was made in view of the above points.

It is an object of the present invention to provide an optical character reading device that has a simple configuration and can perform reliable reading when reading postal codes and the like.

An embodiment of this invention will be described below with reference to the drawings.

In FIG. 4, 21 is a lamp. 22 is a lens for condensing the light from the lamp 21 and irradiating it onto the letter 1 shown in FIG. A solid-state image sensor that forms an image, 25 is a lens for condensing the reflected light from the letter 1 onto the stripe filter 23, and 26 is a lens for focusing the transmitted light of the stripe filter 23 on the image sensor 24.

Therefore, the spectral transmission characteristics of the above stripe filter 230 have two channels of characteristics A and B, with characteristic A transmitting only red wavelengths, and special characteristic B transmitting visible light excluding red wavelengths. The structure of this stripe filter 23 is shown in FIG.

According to FIG. 5, the two channels are arranged alternately.

In FIG. 5, A1*A2...A indicates a filter group exhibiting characteristic A, and B1, B2...Bn
indicates a filter group exhibiting characteristics BY.

and. Needless to say, the number of constituent hits of characteristics A and B are arranged so as to match the number of bits of the image sensor 24.

Further, the lens 26 is for focusing the transmitted light of each bit of the stripe filter 23 onto one pit of the image sensor 24.

Further, as shown in FIG. 6, the image sensor 24 is arranged every other bit in odd and even video groups.

In FIG. 6, 31 is an even video shift register;
32 is an odd video system shift register, 331.332.
. . 33n is a photodiode, 34 is an even video line, and 35 is an odd video line.

That is, odd video line signals and even video line signals can be taken out separately from the image sensor 24.

In other words. Odd video line 3 of iK image sensor 24
5 out of the transmitted light from the stripe filter 23.

Only wavelengths having characteristic A are imaged, and among the transmitted light from the stripe filter 23, the even-numbered video lines 34 are
If only wavelengths having characteristic B are imaged, character signals can be extracted from the odd video lines 35 of the image sensor 24, and frame signals can be extracted from the even video lines 34.

These character signals and frame signals are sent to a logic circuit (not shown) for identification, and the postal code is read.

By adopting the above method, it is no longer necessary to register the literature department and the frame side as in the past.
A single image sensor can also be used to reduce the size and cost.

Although the above embodiment describes an example in which the device is used in a postal code reading device, the present invention is not limited to this and can be applied to devices that read characters written in a frame. In the embodiment described above, the type of spectral transmission characteristic of the stripe filter was selected as two channels, but the number of channels is not limited to two channels, and can be selected in various ways depending on the object to be read.

As described above, according to this invention, when reading a postal code, etc., the reflected light from one sheet of paper is separated into two channels of transmitted light using a stripe filter.

This transmitted light is focused on an image sensor consisting of two video lines (odd and even) through a condenser lens, and signals in different wavelength ranges are extracted from the two video lines from this image sensor. Therefore, it is possible to provide an optical character reading device that requires only one image sensor, reduces the size of the entire device, reduces costs, and has excellent reliability.

[Brief explanation of drawings]

Figure 1 is a plan view showing an example of a letter, Figure 2 is a configuration diagram showing a conventional reading device, Figures 3a and b are diagrams showing the characters and frames read by Figure 2, and Figure 4 is a diagram showing the structure of a conventional reading device. FIG. 1 is a configuration diagram showing a reading device according to an embodiment of the invention. FIG. 5 is an enlarged view of the stripe filter shown in FIG. 4, and FIG. 6 is a basic configuration diagram of the image sensor shown in FIG. 4. 1... Letter, 2... Postal code entry frame (
Red frame). 21... Lamp, 23... Stripe filter. 24...Image sensor 1°

Claims (1)

[Scope of utility model registration request] a light source that irradiates light onto a sheet of paper to be read; a first optical system that focuses light from the light source within a predetermined range of the sheet of paper; and a plurality of channels of light reflected from the sheet of paper with specific spectral wavelengths. an image sensor consisting of a multi-bit stripe filter that is separated into two parts, a multi-bit light-receiving element facing each bit of the stripe filter, and converting each transmitted light of the filter into an electrical signal; An optical character reading device comprising: a second optical system that focuses each transmitted light onto a corresponding light receiving element of the image sensor.