JP3209395B2 - Image information processing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an image information processing apparatus.

[0002]

2. Description of the Related Art FIG. 3 schematically shows a basic configuration of an image information processing apparatus. In the figure, reference numeral 10 denotes a subject such as a passbook, for example, and reference numerals 1a to 1f denote LEDs arranged in a single row along a longitudinal direction (horizontal direction in the drawing) of the subject 10 or multiple rows in a direction perpendicular to the paper surface. (Light-emitting diodes) and the like.
Are irradiated to these LEDs 1a to 1f. The irradiated subject 10 is, for example, a CCD (Charge Coupled Device).
e) An image is picked up by an image sensor 2 such as a line sensor or an area sensor, and analog image data from this image sensor 2 is converted into digital image data by an A / D converter 3 based on a white reference and a black reference. You.

In the image information processing apparatus described above, the white reference is a shading wave learned in advance (see a waveform X indicated by a solid line in FIG. 5), and the shading learning takes in a read waveform obtained by reading a white reference subject. This is done by doing. Therefore, when an image is taken of a plain subject, the analog image data (actual read wave) from the image sensor becomes similar to the learned shading wave.

At this time, the gain of the shading wave is controlled so that the amplitude of the shading wave matches the amplitude of the actual read wave. Therefore, the waveforms are similar and have the same amplitude, so that both waveforms are exactly the same.

[0005]

However, at the time of actual reading, the distance between the subject 10 and the subject 10 may be different from that at the time of learning the shading wave due to, for example, the subject 10 being warped, bent, or inclined. In such a case, the two waveforms will not be similar. That is, when the subject 10 warps so that the illustrated right end moves away from the image information processing apparatus, for example, as indicated by a solid line in FIG. 4, the illustrated right end of the read wave Y corresponding to the warp is ,
As shown in FIG. 5A, the image becomes darker than the right end of the shading wave X, and the right end in the drawing approaches the image information processing apparatus, for example, as indicated by a virtual line in FIG. In such a case, the right end of the read wave Z corresponding to the warp becomes brighter than the right end of the shading wave X, as shown in FIG.

As described above, when the object 10 is warped, for example, the read waves Y and Z and the shading wave X are greatly different in the vicinity of the end of the waveform, and a shading difference occurs as shown in FIG. There is a problem that the shape is not similar and the digitizing accuracy is reduced.

Accordingly, the present invention provides an image information processing apparatus capable of reducing the shading difference caused by, for example, warpage of an object, making the shading wave and the actual read wave similar, and improving the digitizing accuracy. The purpose is to provide.

[0008]

According to a first aspect of the present invention, there is provided an image information processing apparatus which irradiates a subject with a plurality of light emitting elements arranged in parallel, and irradiates the illuminated subject with the subject. An image is taken by an image sensor placed at an appropriate distance from, and analog image data from this image sensor is converted into digital image data by an A / D converter based on a shading wave and a black reference stored in advance by shading learning. The output of the analog image data and the output of the shading wave are detected at predetermined intervals in the image information processing apparatus configured to
The two outputs are compared, and the object and the image are compared.
The distance to the disensor is different from that during the shading learning.
An error detection circuit for detecting the output difference generated at a predetermined interval in the case that, in a direction to reduce the above-described output difference in accordance with the output of the error detection circuit, corresponding to the portion that has occurred the output difference
By controlling the light amount of the light emitting element, and the shading wave
A light amount control circuit for making the analog image data similar to the analog image data .

According to a second aspect of the present invention, in order to achieve the above object, in addition to the first aspect, the image information processing apparatus generates an output difference.
The light emitting element corresponding to the portion where the light emitting element is located is a light emitting element on the outside in the longitudinal direction among the light emitting elements arranged in parallel.

According to the image information processing apparatus of the first or second aspect, for example, the error detection circuit is used to capture a portion where the difference between analog image data from the image sensor and a previously stored shading wave becomes large. The difference between the portions corresponding to the outside in the longitudinal direction of the subject is detected at predetermined intervals, and the light amount control circuit reduces the difference in accordance with the output of the error detection circuit, and the light emission substantially corresponds to the portion where the difference increases. For example, among the light emitting elements arranged in parallel, the light quantity of the light emitting element on the outside in the longitudinal direction is controlled. Therefore, the shading difference caused by, for example, warpage of the subject is reduced, and the shading wave and the actual analog image data (read wave) are made similar.

[0011] Image processing apparatus according to claim 3, in order to achieve the above object, in addition to claim 1, the presence or absence of light quantity control of the light emitting elements of the light amount control circuit, Shejin
Switching means for switching not to be performed during learning .

According to the image information processing apparatus of the third aspect, the light amount control for the light emitting element by the light amount control circuit is not performed by the switching means as needed, for example, during shading learning. During shading learning, normal shading learning is performed to obtain an optimal shading wave.

[0013] Image processing apparatus according to claim 4, in order to achieve the above object, in addition to claim 1, comprising a low pass filter for smoothing the output of the error detecting circuit, the time constant of the low-pass filter, The subject and the image sensor
It is characterized in that it is set to be long enough to follow a change in the distance to the satellite.

According to the image information processing apparatus of the fourth aspect, the output of the error detection circuit is smoothed by the low-pass filter, the influence of the subject such as characters and patterns is reduced, and the low-pass filter is used. According to the time constant set to be longer, the object follows, for example, a warp or the like.

The image processing apparatus according to claim 5, in order to achieve the above object, in addition to claim 1 or 4, the error detection circuit, a predetermined difference between the output of the shading wave at the output of the analog image data A read-and-hold sample-and-hold circuit that samples and holds at intervals of
A shading wave sample-and-hold circuit that samples and holds the difference in output at a predetermined interval; and a bottom-hold circuit that holds the bottom level of the output of the read-wave sample-and-hold circuit. A time constant is set, and a difference between the output of the bottom hold circuit and the output of the shading wave sample and hold circuit is detected.

According to the image information processing apparatus of the fifth aspect, the read-wave sample-and-hold circuit uses
The portion where the difference from the shading wave in the analog image data is large is sampled and held at a predetermined interval,
The shading wave sample and hold circuit samples and holds the portion where the difference in the shading wave becomes large at predetermined intervals, the bottom hold circuit holds the bottom level of the output of the read wave sample and hold circuit, and the bottom hold circuit The difference between the output according to the arbitrary time constant and the output of the shading wave sample and hold circuit is detected and becomes the error detection circuit output.
Since the bottom level of the output of the read wave sample and hold circuit is held by the bottom hold circuit,
The influence of the subject, for example, characters, patterns, etc. is reduced, and the subject can follow, for example, warp, etc. with an arbitrary time constant of the bottom hold circuit.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram illustrating an image information processing apparatus according to an embodiment of the present invention. In the figure, reference numeral L denotes an LED group as a light emitting element for irradiating the subject 10 (see FIG. 3) such as a passbook, for example. Each of the LEDs 1a to 1f constituting the LED group L is actually As shown in FIG. 3, they are arranged in a single row along the longitudinal direction of the subject 10 (see FIG. 3) or in multiple rows in a direction perpendicular to the plane of FIG. These LEDs 1a to 1f
Is connected to the constant current circuit 5, and the LED 1a
The total light amount of 1 to 1f is controlled by the total light amount control means 4 according to a PWM (pulse width modulation) signal. Then, the amplitude of the read wave (analog image data) is
For example, the total light amount of the LEDs 1a to 1f is set to 1 volt.

The subject 10 irradiated to the LEDs 1a to 1f
Is imaged by an image sensor 2 such as a line sensor or an area sensor composed of, for example, a CCD (Charge Coupled Device). The analog image data from the image sensor 2 is amplified by an amplifier 6, and the A / D converter 3
Is input to

The analog image data from the image sensor 2 is also input to a bottom hold circuit 7, which holds the bottom level of the analog image data. That is, as shown in FIG. 5, since the analog image data is negative data with respect to the Ref (reference) voltage serving as the black reference, the bottom level (the lowest point in the figure) is held. Then, the digital value which has been subjected to the shading learning and stored in advance is analog-converted by the D / A converter 8 based on the bottom level and output as a shading wave. That is, the bottom level of the shading wave is determined by the bottom level of the bottom hold circuit 7, and its amplitude is made equal to the amplitude of the read wave. Then, the shading wave whose amplitude is made the same as the amplitude of the read wave is input to the A / D converter 3.

The A / D converter 3 has an R signal of, for example, 5 volts, which serves as a black reference, in addition to the read wave and the shading wave described above.
The ef voltage is input. Therefore, the read wave is converted into digital image data by the A / D converter 3 based on the shading wave and the black reference.

Here, if the object 10 has the above-described warpage, bending, inclination, etc., the distance between the object 10 and the read wave and the shading wave are different from each other when the shading wave is learned. Instead, the digitizing accuracy is reduced.

Therefore, in the present embodiment, an error detection circuit 9 which takes in the read wave and the shading wave and detects a difference between portions where the difference between the read wave and the shading wave becomes large at predetermined intervals, In the direction of reducing the difference in accordance with the output of the detection circuit 9, a light amount control circuit 15 for controlling the light amount of the LED substantially corresponding to a portion where the difference increases.
a and 15b.

The error detection circuit 9 includes a first read-wave sample-hold circuit 9a that samples and holds the read wave at a predetermined time interval according to the first timing signal, and a shading wave for a predetermined time according to the first timing signal. A first shading wave sample and hold circuit 9aa for sampling and holding at an interval, a second reading wave sample and hold circuit 9b for sampling and holding a reading wave at predetermined time intervals according to a second timing signal, The second sample-and-hold circuit 9bb for sampling and holding at a predetermined time interval according to the timing signal 2 and the first sample-and-hold circuits 9a and 9aa compare the outputs of the first sample-and-hold circuits 9aa and 9aa to output a first error signal. And the second sample-and-hold circuits 9b and 9bb A second comparator 11b for outputting a second error signal by comparing the output, and a.

Sample hold circuits 9a, 9aa, 9
b and 9bb are each composed of, for example, an analog switch and a capacitor. Further, the timing based on the first timing signal is, for example, the subject 10
3 corresponds to the left end portion in FIG. 3 (the lower right portion of the solid line shown in FIG. 5), and the timing according to the second timing signal is the same as that in FIG. It corresponds to the right end portion (the portion to the right of the solid line shown in FIG. 5).

Therefore, the first comparator 11a outputs the difference (first error signal) between the read wave and the shading wave at the left end of the subject 10 in the longitudinal direction (see FIG. 3), and outputs the second error signal. The comparator 11b outputs a difference (second error signal) between the read wave and the shading wave at the right end of the subject 10 in the longitudinal direction (see FIG. 3).

Low-pass filters 12a and 12b are connected to the first and second comparators 11a and 11b, respectively. Therefore, the first and second error signals are smoothed by the low-pass filters 12a and 12b, respectively, so that the influence of, for example, characters and patterns is reduced. Also, these low-pass filters 12a, 1
The time constant of 2b is set to be longer, so that the object 10 has a follow-up property with respect to, for example, warpage.

Each of the low-pass filters 12a and 12b has a light amount control circuit 1 comprising an npn transistor, for example.
5a and 15b are respectively connected. That is, the output terminal of the low-pass filter 12a is connected to the base of the first transistor 15a, and the LED 1a,
1b, the emitter is connected to the ground, the output terminal of the low-pass filter 12b is connected to the base of the second transistor 15b, and the LE is connected to the collector.
D1e and 1f are connected to the ground of the emitter, respectively.

Therefore, as shown by the solid line in FIG. 4, for example, when the subject 10 warps upward in the figure (the read wave corresponds to FIG. 5A), the second error signal due to the shading difference is generated. As a result, the light quantity control circuit 15b acts to cancel the second error signal (reduce the difference). That is, according to the second transistor 15b, the LEDs 1e, 1
The current of f increases, and the light amount of the LEDs 1e and 1f is increased.

As shown by the imaginary line in FIG. 4, for example, when the object 10 warps downward in the figure (the read wave corresponds to FIG. 5B), the second error signal due to the shading difference is generated. Occurs, and LE is generated according to the second transistor 15b.
The current of D1e, 1f decreases, and the light amount of the LEDs 1e, 1f is weakened.

When the subject 10 is warped to the left as shown in the figure, a first error signal is generated due to a shading difference, and the LED 1 is turned on according to the first transistor 15a.
When the current of the LEDs 1a and 1b increases and the amount of light of the LEDs 1a and 1b increases, for example, when the subject 10 warps to the lower left in the figure, a first error signal due to a shading difference is generated, and the first error signal is generated according to the first transistor 15a. LED 1a, 1
The current of b decreases, and the light amount of the LEDs 1a and 1b is weakened.

As described above, in the present embodiment, for example, an image is taken by the error detection circuit 9 as a portion where the difference between the read wave (analog image data) from the image sensor 2 and the previously stored shading wave becomes large. The difference between the portions corresponding to the outside of the subject 10 in the longitudinal direction is detected at predetermined intervals, and the difference is reduced in a direction in which the difference is reduced in accordance with the output of the error detection circuit 9 by, for example, transistors 15a and 15b as a light amount control circuit. L in the longitudinal direction out of the LEDs 1a to 1f approximately corresponding to the larger portion
The light amounts of the EDs 1e and 1f (1a and 1b) are controlled to reduce the shading difference caused by, for example, warpage of the subject 10 so that the shading wave and the actual read wave (analog image data) are made similar. Therefore, it is possible to improve the digitizing accuracy.

The output of the error detection circuit 9 is smoothed by the low-pass filters 12a and 12b to reduce the influence of, for example, characters and patterns on the subject 10, and the time constant set to be longer than the low-pass filters 12a and 12b. Thus, the object 10 is made to have a follow-up property with respect to, for example, warpage, so that the above-described effect can be further enhanced.

Here, for example, at the time of shading learning, the LED is set so that the amplitude of the read wave becomes, for example, 1 volt.
When setting the light amounts of the whole 1a to 1f, the similarity compensation as described above is not performed. That is, the transistor 1
It is necessary to provide a switching unit that does not temporarily control the light amount of the LEDs a, b (e, f) by the LEDs 5a, 15b.

Therefore, in the present embodiment, the low-pass filters 12a and 12b and the transistors 15a and 15b
Switching means 13 capable of switching the application of the default voltage is provided between each of the bases.

That is, the default voltage is applied by the switching of the switching means 13, and the transistors 15a, 1
5b so that the light amount control for the LEDs 1e, 1f (1a, 1b) is not performed at the time of shading learning,
At the time of shading learning, normal shading learning is performed to obtain an optimal shading wave, so that the above-described effects can be further enhanced.

By the way, when reading waves are sampled and held by the reading wave sample and hold circuits 9a and 9aa, if there are, for example, characters or patterns, an inappropriate level is sampled and held.

Therefore, in the present embodiment, a countermeasure as shown in FIG. That is, the first bottom hold circuit 14a that holds the bottom level of the output of the first read wave sample / hold circuit 9a is provided between the first read wave sample / hold circuit 9a and the first comparator 11a. , Between the second read-wave sample-and-hold circuit 9b and the second comparator 11b.
A second bottom hold circuit 14 that holds the bottom level of the output of the second read-wave sample-hold circuit 9b
b are provided respectively.

Accordingly, as described above, when reading waves are sampled and held by the reading wave sample and hold circuits 9a and 9b, even if there are, for example, characters, patterns, and the like, the bottom hold circuits 14a and 14b use the bottom level circuits 14a and 14b. The level without characters, patterns, etc. is held, and the influence of the characters, patterns, etc. is reduced.

However, if the bottom level is kept held in this way, it becomes impossible to cope with the warpage of the subject 10 (warpage is no longer detected). Accordingly, in the present embodiment, these bottom hold circuits 14a,
14b, discharge resistors 14aa and 14bb are provided, respectively, so that the discharge is gradually performed so that the bottom level can gradually follow the warpage.

That is, the bottom hold circuits 14a, 1
4b holds the bottom level of the output of the read-wave sample-hold circuits 9a and 9b, thereby reducing the influence of the subject 10 due to, for example, characters and patterns, and the discharge resistance 14a of the bottom-hold circuits 14a and 14b.
Since a and 14bb (arbitrary time constants) are made to follow the object 10 such as warpage, the above-described effects can be further enhanced.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the invention. Needless to say, for example, in the above-described embodiment, an LED that roughly corresponds to a portion where the difference between the read wave and the shading wave is large is:
The left end in FIG. 3 is a pair of LEDs 1a and 1b, and the right end in FIG. 3 is a pair of LEDs 1e and 1f, but is not limited thereto.
For example, at the left end in FIG.
a, the outermost LED 1f at the right end in FIG.
It is good. Also, LEDs 1a, 1b (1e, 1f)
Can be connected to different transistors, respectively, to control the light amount more optimally. Furthermore, the control is not limited to the LEDs on both sides.

In the above embodiment, the light emitting element is an LED as the optimum one. However, the light emitting element can be replaced with, for example, an incandescent lamp.

[0043]

As described above, according to the image information processing apparatus of the first or second aspect, the difference between the analog image data from the image sensor and the previously stored shading wave is increased by the error detection circuit. For example, a difference between portions corresponding to the outside of the imaged subject in the longitudinal direction is detected at predetermined intervals, and the light amount control circuit reduces the difference in accordance with the output of the error detection circuit. For example, by controlling the light amount of the light-emitting elements on the outside in the longitudinal direction among the light-emitting elements arranged side by side as the light-emitting elements corresponding to the shading wave and the actual analog image by reducing the shading difference caused by, for example, warpage of the subject. Since the data (read wave) is configured to have a similar shape, the digitizing accuracy can be improved.

According to the image information processing apparatus of the third aspect, in addition to the first aspect, the light amount control of the light emitting element by the light amount control circuit is performed by the switching means as required, for example, during shading learning. Since the shading learning is not performed and the normal shading learning is performed so as to obtain an optimal shading wave, the above-described effect can be further enhanced.

According to a fourth aspect of the present invention, in addition to the first aspect, the output of the error detection circuit is smoothed by a low-pass filter to reduce the influence of a subject, for example, a character or a pattern. Since the low-pass filter is configured to have a follow-up property with respect to, for example, warpage of the subject by using a longer time constant, the above-described effect can be further enhanced.

According to a fifth aspect of the present invention, in addition to the first or fourth aspect, a portion where the difference from the shading wave in the analog image data becomes large is determined by the read-wave sample-and-hold circuit. Sample and hold at intervals, sample and hold the shading wave in the portion where the difference is large by the shading wave sample and hold circuit at predetermined intervals, and hold the bottom level of the output of the read wave sample and hold circuit by the bottom hold circuit. Then, the difference between the output of the bottom hold circuit according to an arbitrary time constant and the output of the shading wave sample hold circuit is detected and output as an error detection circuit, and the bottom hold circuit outputs the bottom of the output of the read wave sample hold circuit. By holding the level, for example, Character, the influence of the pattern or the like is reduced,
In addition, since the configuration is such that an arbitrary time constant of the bottom hold circuit can follow a subject such as a warp, the above-described effect can be further enhanced.

[Brief description of the drawings]

FIG. 1 is a circuit diagram illustrating an image information processing apparatus according to an embodiment of the present invention.

FIG. 2 is a circuit diagram illustrating another example of the error detection circuit in the image information processing apparatus.

FIG. 3 is a schematic diagram of a basic configuration of an image information processing apparatus.

FIG. 4 is a schematic diagram for explaining the warpage of a subject.

5A and 5B are diagrams illustrating a relationship between a shading wave and a read wave when a subject warps, in which FIG. 5A illustrates a case where the subject warps as indicated by a solid line in FIG. This is when warped as shown by the imaginary line in FIG.

[Explanation of symbols]

1a to 1f Light emitting element 2 Image sensor 3 A / D converter 9 Error detection circuit 9a, 9b Sample hold circuit for reading wave 9aa, 9bb Sample hold circuit for shading wave 10 Subject 11a, 11b Comparator 12a, 12b Low pass filter 13 Switching Means 14a, 14b Bottom hold circuit 14aa, 14bb Discharge resistor 15a, 15b Light quantity control circuit X Shading wave Y, Z Analog image data

Claims (5)

(57) [Claims] An object is illuminated by a plurality of juxtaposed light-emitting elements, and the illuminated object is appropriately removed from the object.
Captured by an image sensor at a distance of, the analog image data from the image sensor, previously Sheji
An image information processing apparatus configured to convert the digital image data by A / D converter on the basis of the shading wave and black reference stored by ring learning, an output of the analog image data of the shading wave
Output at predetermined intervals, and these two outputs
Comparing the distance between the subject and the image sensor.
An error detection circuit for detecting an output <br/> difference generated when the release is different from when the shading learning at predetermined intervals, in a direction to reduce the above-described output difference in accordance with the output of the error detecting circuit, has occurred the output difference part by controlling the light amount of the light emitting elements corresponding to the said shading wave Ana that
An image information processing apparatus, comprising: a light amount control circuit for making log image data similar . 2. The image processing apparatus according to claim 1, wherein, the light emitting elements corresponding to the portion that occurs the output difference before
Image information processing apparatus, characterized in that the longitudinal outer light emitting elements of the serial juxtaposed light emitting element. 3. An image processing apparatus according to claim 1, wherein the presence or absence of the light amount control with respect to the light emitting element by the light amount control circuit, the switching <br/> obtain switching means so as not performed when shading learning An image information processing apparatus provided with. 4. The image information processing apparatus according to claim 1, further comprising: a low-pass filter for smoothing an output of said error detection circuit, wherein a time constant of said low-pass filter is set to a value between said subject and said input signal.
An image information processing apparatus which is set to be long enough to follow a change in the distance between the image sensor and the image sensor . 5. An image information processing apparatus according to claim 1 or 4, wherein the error detection circuit, out of the shading wave at the output of the analog image data
A read-wave sample-hold circuit that samples and holds a difference from a force at a predetermined interval; a shading-wave sample-hold circuit that samples and holds the difference in the output of a shading wave at a predetermined interval; and the read-wave sample-hold circuit. And a bottom hold circuit for holding a bottom level of the output of the above. An arbitrary time constant is set in the bottom hold circuit, and the difference between the output of the bottom hold circuit and the output of the shading wave sample hold circuit is calculated. An image information processing apparatus characterized by detecting.