JPS6349830B2 - - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention is directed to manual scanning of character information consisting of a plurality of characters recorded on, for example, a price tag, using a hand-held reader. The present invention relates to an information reading device that optically reads information.

(Prior Art) Recently, as an information input means, a hand-held reading means called a hand scanner, which optically directly reads character information consisting of a plurality of numbers or letters recorded on a recording medium such as a price tag, has been provided. Various types of optical information reading devices have been developed and put into practical use. In these information reading devices, there are cases where there is no distance between the tip of the handheld reading means and the surface of the recording medium, that is, when the tip of the reading means is in close contact with the surface of the recording medium. It is necessary to reliably read the character information on the recording medium even if there is a gap of about 1.0 mm. However, when the gap becomes extremely large, a certain image is formed on the surface of the photoelectric conversion element within the reading means, and is captured as an extremely small image due to optical action. Therefore, in such a case, character recognition may become impossible or may lead to misreading. In this case, abnormal information may be input, or it may become impossible to read only accurate information.

(Problems to be Solved by the Invention) As described above, it has been impossible for the information reading device including the conventional hand-held reading means to read only accurate information.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an information reading device that can eliminate the above-mentioned drawbacks, prevent the input of abnormal information, and reliably read only more accurate information.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention detects the level of a read signal output from a reading means in an information reading device and sets a predetermined value in advance. The present invention is characterized in that the conduction of the read signal outputted from the reading means is controlled based on the detection result and an operation control signal inputted from the outside.

(Operation) According to the present invention, the read signal output from the reading means is not directly subjected to processing. The level of the read signal output from the reading means is detected. This detected level is compared with a set value in terms of magnitude. Next, this comparison result and an externally inputted operation control signal are supplied to the gate means. The gating means controls conduction of the read signal based on the input. This allows the information reading device to read information accurately.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a hand-held reader, in which a main body 2 includes a light source 3 that irradiates light onto a recording medium P such as a price tag, and a light source 3 that emits light reflected from the recording medium P through an optical system 4. Photoelectric conversion prevention 5
etc. are stored. Output of the above reader 1,
That is, the output signal of the photoelectric conversion blocker 5 is supplied to the video signal amplifier 7 via the cable 6, and the output of this amplifier 7 is supplied to the level detection circuit 8. This level detection circuit 8 is for determining the distance l between the tip of the reader 1 and the surface of the recording medium P based on the optical reflectivity of the recording medium P. This circuit 8
is a peak value detection circuit 9 consisting of, for example, a diode D, a capacitor C, and a resistor R, and a comparator 10.
It consists of This comparator 10 detects the peak value or compares the output of the circuit 9 with a reference voltage E that is set corresponding to a pre-readable value, and depending on the comparison result, it has two values of "1" and "0". Outputs a conversion signal. The output of the level detection circuit 8 is the gate circuit 1
1, and this gate circuit 1
1 is supplied with a control signal from an external interface (not shown). Here, the gate circuit 11 performs a logical product (AND) of two inputs.
The negation of is performed using three circuits and is well known. Generally, the output of the gate circuit 11 is supplied to the signal control circuit 12 together with the output of the amplifier 7. This signal control circuit 12 controls the output signal of the amplifier 7 according to the output of the gate circuit 11, and includes an NPN type transistor 13 connected as an emitter follower to which the signal of the amplifier 7 is supplied with good timing, and this transistor. It is connected between the emitter side of gate circuit 13 and ground and is turned on by the output signal of gate circuit 11.
It is mainly composed of an NPN type transistor 14 which is turned off. The output of the signal control circuit 12, that is, the signal output from the emitter of the transistor 13, is supplied to a subsequent signal processing section, for example, a quantization circuit 15.

In this configuration, when manual scanning is performed by holding the reader 1 in hand and moving it in a predetermined direction over the recording medium P, the light from the light source 3 is irradiated onto the recording medium P. The reflected light is imaged on a photoelectric conversion element 5 via an optical system 4 and converted into an electrical signal. The output signal of this photoelectric conversion element 5 is amplified by an amplifier 7 and then supplied to a level detection circuit 8. The level detection circuit 8 determines whether the distance l is a predetermined distance or not based on the signal. If the recording medium P is illuminated by the light source 3, the brightness that the photoelectric conversion element 5 senses is determined by the light reflectance of the recording medium P. That is,
If the distance l between the tip of the reader 1 and the surface of the recording medium P is [l=0], the signal amplitude will be large,
It is clear that under the condition [l>0], the larger the distance l becomes, the smaller the signal amplitude becomes.

By utilizing such an effect, the above distance l
The details are explained below. Now, as the output signal A of the amplifier 7, if [l=0], for example, a signal _A1 as shown by the solid line in Figure 2a is obtained, and if the distance l becomes large, a signal _A2 as shown in the figure Suppose that we obtain this signal
A ₁ and A ₂ , that is, the output signal A of the amplifier 7 is supplied to a peak value detection circuit 9 . Here, by making the values of the capacitor C and the resistor R, which determine the charging/discharging time constants, very large, the output signal B of the peak value detection circuit 9 is transmitted to the amplifier as shown by the broken line in FIG. 2a. 7 is expressed as a substantially DC voltage component according to the amplitude of the output signal. However, comparator 10
compares the output signal B and the reference voltage E,
If [B>E], a “1” signal is output, and if [B<E], a “0” signal is output. In this way, the distance l is detected, and if the distance l is smaller than a preset value, a "1" signal is output, and if it is larger, a "0" signal is output. Note that the reference voltage E is desirably set to a value corresponding to the signal amplitude value when the distance l becomes approximately 5 mm experimentally.

Therefore, when the output of the level detection circuit 8 is a "1" signal, if the control signal from the external interface is a "1" signal, the output of the gate circuit 11 is a "0" signal. Therefore, the transistor 14 is turned off, and the output signal of the amplifier 7 (video signal A) is sent to the quantization circuit 15 through the transistor 13, and predetermined signal processing is performed.
When the output of the level detection circuit 8 is a "0" signal, even if the above control signal is a "1" signal, the NAND circuit 1
1 becomes the "1" signal, so the transistor 14 is turned on, and the output signal A of the amplifier 7 becomes the "1" signal.
is held at the emitter potential of transistor 14. That is, in this circuit, the signal A is at ground potential (zero volts), and no matter what signal is input, no signal is sent out thereafter.

In this way, the output of the level detection circuit 8 is “1”
In the case of a signal, that is, if the distance l is smaller than a predetermined value, the read signal obtained from the reader 1 is processed, and if the output of the level detection circuit 8 is a "0" signal, that is, the distance If l is larger than a predetermined value, processing of the read signal is stopped. Therefore, it is possible to eliminate unrecognizable characters or misreadings caused by the extremely large distance l, prevent abnormal information from being input, and read only more accurate information.

In the above embodiment, before the read signal obtained from the reader is quantized,
Although the control is performed according to the output of the level detection circuit, similar effects can be obtained even if the control is performed after the quantization process is performed. Specifically, as shown in FIG. 3, for example, the output signal of the amplifier 7 is directly supplied to the quantization circuit 15 and quantized, and then the output signal of the level detection circuit 8 and the control signal from the IBU interface are sent to the gate. Supplied to circuit 16. The output of this gate circuit 16 is sent to a character detection/cutout section 17, and the output of this character detection/cutout section 17 is sent to a character recognition section 18. Here, the gate circuit 16 is a circuit that realizes logical product of two inputs. Therefore, in this case, if at least one of the output of the level detection circuit 8 and the control signal is a "0" signal, the quantization circuit 1
The output (character signal) of 5 is not transmitted thereafter.

[Effects of the Invention] As detailed above, according to the present invention, it is detected whether the output of the hand-held reading means has reached a predetermined level, and based on this detection result and an external control signal, the hand-held By controlling the processing of the read signal obtained from the type reader, it is possible to provide an information reading device that can prevent the input of abnormal information and reliably read only more accurate information.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
Figures a and b are main signal waveform diagrams for explaining the operation of the same embodiment, and Fig. 3 is a configuration diagram showing another embodiment of the present invention. P...Recording medium, 1...Hand-held reader, 8...
Level detection circuit, 11, 16...gate circuit, 1
2...Signal control circuit, 15...Quantization circuit.

Claims (1)

[Claims] 1. Manually scanning the recording medium with a reading means,
In an information reading device that reads the information by obtaining a reading signal corresponding to the information on the storage medium, detecting the level of the reading signal output from the reading means and determining whether the level of the reading signal output from the reading means is greater than a predetermined value set in advance. The present invention is characterized by comprising: a detection means for detecting whether the detection means is active, and a gate means for controlling conduction of the read signal output from the reading means based on the output of the detection means and an operation control signal input from the outside. Information reading device.