JPH09266525A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep the resolution of a photodetecting signal without depending on the intensity change of external light by providing a gain control means for changing a gain on the stage to process the photodetecting signal or a photodetecting time control means for changing the photodetecting time of a photodetection part. SOLUTION: In the state of just making external light incident, a photodetecting signal S is preserved in a field memory 30 as digital signal data. Thus, a signal subtracting the photodetecting signal S in the state of just making the external light incident from a photodetecting signal, for which a halogen lamp 40 is turned on in the state of making the external light incident, can be provided. In that case, when the external light or the quantity of light from a light source is changed corresponding to a reading position, the gain in the state of generating an image corresponding to the change in the known or detected quantity of light is controlled and the intensity ratio of the photodetecting signal can be made almost constant. Besides, by controlling the photodetecting time while recognizing the photodetecting signal S preserved in the field memory 30 and illuminance data in a ROM 70 for illuminance distribution data, the resolution of the photodetecting signal can be kept without depending on reflected light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has an image reading apparatus having means for holding the illuminance of external light and capable of generating an image which is not affected by the external light under each environment even when the external light is incident. Is provided.

[0002]

2. Description of the Related Art Conventionally, in a monaural image reading apparatus, the ratio of the amount of reflected light of the external light in the reflected light is determined by reading with a structure that shields the external light or by using a light source of light brightness such as a halogen lamp. I reduced the number and read the image. However, even with this method, the influence of outside light cannot be excluded, and different images can be obtained depending on the difference in outside light environment.
JP-A-2-26657 is a patent for changing the light amount of the LED light source according to the intensity of external light, but this has a different problem to be solved from the present invention, and the content is to keep the sum of the external light intensity and the LED light source intensity constant. Is. Japanese Patent Laid-Open No. 4-178788 discloses a patent for detecting the intensity of external light and controlling the light signal storage time of the line image sensor. However, this has an extra circuit for measuring the intensity of external light for a known amount of light. . In a color image reading apparatus that performs color separation by light sources, when three light sources 1, red, green, and blue 3 for red, green, and blue are individually turned on, the reflected light is read by a light receiving unit 4 and each color is read. An image to be captured was generated, and they were combined to generate a color image. In addition, JP-A-6-15
There is also an invention in which a color image is generated by always turning on only one color and turning off the other two colors as described in 2863. Further, in the case of a color image reading apparatus that performs color separation using color filters, there is a method of capturing a color image using a color CCD in which red, green, and blue color filters are mounted on a solid-state image sensor (CCD). is there. However, in both monaural and color, these methods require use with the outside light blocked in order to obtain an image that is not affected by the outside light. However, these methods cannot produce the same image under each environment because the effect of external light appears on the generated color image.

[0003]

[Problems to be Solved by the Invention]

[Problem of Claim 1] As described above, the conventional technique has a problem that the same image cannot be generated under each environment when external light is incident. An object of the present invention is to provide an image capturing device capable of obtaining a capture target image that is not affected by the illuminance of external light even when external light is incident.

[Problem of Claim 2] As described above, the conventional technique has a problem that the same color image cannot be generated under each environment when external light is incident. An object of the present invention is to provide a color image capturing device capable of obtaining a capture target image that is not affected by the illuminance of external light even when the external light is incident.

[Problem of Claim 3] As described above, the prior art has a problem that the same color image cannot be generated under each environment when external light is incident. An object of the present invention is to provide a color image capturing device capable of obtaining a capture target image that is not affected by the illuminance of external light even when the external light is incident.

[Problem of Claim 4] As described above, in the inventions of Claims 1 to 3, the reflected light from the object to be captured by the external light is received by the light receiving section and is generated, and the external light. And an image is generated based on the reflected light from the capture target by the light source. In this method, when receiving the reflected light from the target to be captured by only the external light, since the external light intensity is unknown, always receive with the same gain, if the external light intensity is strong, in the amplification stage of the received light signal, It is possible that the amplifier gain cannot be normally secured due to the limitation of the dynamic range of the amplifier. It is an object of the present invention to maintain the dynamic range of the received light signal in the image capturing device described in any one of claims 1 to 3 without depending on the change in the external light intensity.

[Problem of Claim 5] As described above, in the inventions of Claims 1 to 3, the reflected light from the object to be captured by the external light is received by the light receiving section and is generated, and the external light. And an image is generated based on the reflected light from the capture target by the light source. In this method, when the light source is fixed and the illuminance is non-uniform in the reading target area by using CCD in the light receiving part, the dynamic range of the CCD is limited, so that the light receiving time is constant over the entire acquisition target area. Then, there is a drawback that the dynamic range of the received light signal is limited by the maximum reflected light amount and the minimum reflected light amount of the capture target area, and the resolution of the received light signal is lowered. The object of the present invention is claim 1.
It is an object of the present invention to maintain the resolution of a light reception signal without depending on the dynamic range of the amount of reflected light from the object to be captured by the light source.

[Problem of Claim 6] Claims 1 to 5
In the inventions up to the above, when a light source with a constant light quantity is used, when the external light intensity increases, the signal of the reflected light quantity from the target to be captured by the external light in the received light signal also increases, and the dynamic range of the light receiving element increases. Is constant, the dynamic range of the signal of the reflected light amount from the object to be captured by the light source is reduced and the resolution is reduced. An object of the present invention is to provide the image capturing device according to any one of claims 1 to 5 without depending on a change in intensity of external light.
The purpose is to maintain the resolution of the received light signal.

[0009]

[Means for Solving the Problems]

[Claim 1] According to the present invention, it is possible to know the influence of external light on the reflected light when a single light source or a plurality of light sources is irradiated by pre-scanning the reflected light from the object to be captured by only the external light. Therefore, the effect of external light is removed.

[Claim 2] The invention of the present application pre-scans the reflected light from the object to be captured by only the external light, thereby reflecting the external light when irradiating the red light source, the green light source and the blue light source. By knowing the effect on light, the effect of external light is removed.

[Claim 3] According to the present invention, the reflected light from the object to be captured by only the external light is pre-scanned through the red filter, the green filter, and the blue filter, so that the red filter and the green filter when the light source is irradiated. By knowing the influence of the external light on the reflected light when passing through the blue filter, the influence of the external light is removed.

[Claim 4] The present invention is claim 1
In the image reading device according to any one of claims 1 to 3, by knowing the illuminance distribution of the external light or the light source to the acquisition target, and adjusting the gain of the received light signal, the reading by the change of the illuminance of the light source to the acquisition target is performed. The effect on the image is removed.

[Claim 5] The present invention is claim 1
In the image reading device according to any one of claims 1 to 3, by knowing the illuminance distribution of the external light or the light source to the acquisition target, and adjusting the light receiving time, a read image due to uneven light source illuminance to the acquisition target is obtained. The effect of is removed.

[Claim 6] The present invention is claim 1
In the image reading device according to the present invention, the intensity of the external light is known and the illuminance of the light source is adjusted to maintain the resolution of the received light signal without depending on the intensity change of the external light.

[Claim 1] In the image reading apparatus according to the present invention, when the external light is incident on the object to be read, the received light signal 1 is obtained only when the external light is incident, and the external light is incident. Therefore, the light receiving signal 1 is subtracted from the light receiving signal when the light source is turned on to obtain a single or a plurality of light receiving signals, and an image is generated based on that. In an environment where external light is incident, it is possible to eliminate the influence of external light on the read image.

[Claim 2] In the color image reading apparatus according to the present invention, when the external light is incident on the object to be read, the received light signal 2 is only when the external light is incident, and the external light is incident. When the red light source is turned on, the received light signal 3, the green light source is turned on when the external light is incident, and the blue light source is turned on when the external light is incident. From the received light signal 5, the received light signal 6 is obtained by subtracting the received light signal 2 from the received light signal 3, the received light signal 7 is obtained by subtracting the received light signal 2 from the received light signal 4, and the received light signal 2 is subtracted from the received light signal 5. Since the color image is generated based on the received light signal 8 and the received light signal 6, the received light signal 7 and the received light signal 8, it is possible to remove the influence of the outside light on the read image in the environment where the outside light is incident. Becomes

[Claim 3] The color image reading apparatus according to the present invention, when external light is incident on the reading object,
The received light signal 9 passing through the red filter only when external light is incident, the received light signal 10 passing through the green filter only when external light is incident, and the blue filter only when external light is incident are displayed. Passed the received light signal 11, the received light signal 12 passed through the green filter when the light source was turned on with the outside light incident, and the passed green signal when the light source was turned on with the outside light entered. From the received light signal 13 and the received light signal 14 obtained by subtracting the received light signal 9 from the received light signal 12 from the received light signal 14 that has passed through the blue filter when the light source is turned on in the state where the outside light is incident, obtain the received light signal 15 from the received light signal 13 Since the light reception signal 16 obtained by subtracting the light reception signal 10 is obtained and the light reception signal 17 obtained by subtracting the light reception signal 11 from the light reception signal 14, a color image is generated based on the light reception signals 15, 16 and 17. , In an environment where light is incident, it is possible to eliminate the influence of external light on the read image.

[Claim 4] In the image reading apparatus according to the present invention, when the external light or the amount of light from the light source changes depending on the reading position, the light received when an image is generated according to a known or detected change in the amount of light. Since the signal gain is adjusted, it is possible to keep the intensity ratio of the received light signal substantially constant under the environment where the illuminance changes in the capturing target area due to the external light or the light source.

[Claim 5] The image reading apparatus according to the present invention adjusts the light receiving time of the light receiving portion according to a known change when the external light or the light amount from the light source changes depending on the reading position. It is possible to maintain the resolution of the received light signal without depending on the dynamic range of the reflected light amount from the capture target.

[Claim 6] The image reading device according to the present invention has a means for detecting the amount of external light when the intensity of external light is increased by using a light source having a constant amount of light, and the amount of external light is large. In this case, the amount of light of the light source is also increased, and the amount of change between the amount of light received when only external light is received and the amount of light received when the external light is incident on the light source to receive light Since there is a means for following the change, it is possible to maintain the resolution of the received light signal without depending on the change in the intensity of outside light.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment] FIG. 1 shows an embodiment of the present invention. FIG.
1 is a schematic diagram of an image reading device, which includes a halogen lamp 40, a light quantity adjusting unit 43, a photo sensor 20, and an A / D converter 2.
1, an optical system 11, a CCD 13, and a scanning motor 12
, Scan adjusting unit 19, light receiving time adjusting unit 18, variable gain difference amplifier 15, gain adjusting unit 14, A / D converter 16, integrator 75, and field memories 30, 31.
, Integrator 76, D / A converter 17 and controller 6
0 and an illuminance distribution data ROM 70.

The function of each block in FIG. 1 will be described. The lens 11 focuses the reflected light from the capture target 10 on the light receiving unit 13. The scanning motor 12 causes the scanning adjustment unit 19 to move the C
The CD 13 is moved to scan the object to be captured. The halogen lamp 40 is controlled by the light amount adjusting unit 43 as a light source. The light receiving unit 13 outputs a light receiving signal according to the reflected light from 10 which is incident during the time adjusted by the light receiving time adjusting unit 18. The variable gain difference amplifier 15 amplifies a signal obtained by subtracting the signal input to the inverting input from the signal input to the non-inverting input to a signal level that can be easily processed in the subsequent stage with the gain set by the gain adjusting unit. The A / D converter 16 converts the received light signal in the analog signal format output from 15 into a digital signal. The integrator 75 restores the compression of the dynamic range of the received light signal, which is performed by the gain adjustment and the light receiving time adjustment. The field memories 30 and 31 store the received light signal value of only the outside light and the received light signal calculation value when the halogen lamp 40 is turned on, respectively, in the range of the target area. Photo sensor 2
0 measures the external light intensity. The A / D converter 21 converts the output from the photo sensor 20 into a digital signal. The integrator 76 integrates 30 data according to the dynamic range of the received light signal. The D / A converter 17 creates a differential signal of the received light signal from the output of 76. ROM for illuminance distribution data
Reference numeral 70 indicates the illuminance distribution data on the document table 80 when the light source is illuminated. The controller 60 controls the electric system.

FIG. 2 is a main flowchart of the first embodiment,
FIG. 3 shows a flow chart of image reading using only external light, FIG. 4 shows a flow chart of image reading at the time of light source irradiation, and FIG. 5 shows a flow chart of light reception signal amplification at the time of light source irradiation. The present embodiment will be described according to the flowcharts using FIGS. 1 to 5 described above.

First, as shown in S1, the image is read only by the external light. In S10, the controller 60 measures the external light intensity with the photo sensor 20, and S11
At the gain adjusting unit 1
By writing in 4, the gain of the variable gain difference amplifier 15 is set. Next, in S12, the light receiving time t1 is written in the light receiving time adjusting unit 18 to set the light receiving time of the CCD 13. In S13, the scanning adjustment unit 19 writes the scanning data into the scanning adjustment unit 19 so that the CCD adjusts the light reception and scanning of the CCD. In S14, the reflected light when only the external light from the capture target 10 is irradiated is imaged on the CCD 13 by the lens 11. In S15, CCD1
The light-reception signal output from 3 is amplified A1 times by the variable gain difference amplifier 15 and input to the A / D converter 16. In S16, the A / D converter 16 converts the received light signal into a digital signal and outputs it to the integrator 75. A magnification of 1 is set in the integrator 75 by the controller 60, and the received light signal that has been converted into a digital signal is directly written in the field memory 30 in S17I. S13 and subsequent steps are continuously performed until the scanning is completed.

Then, the process proceeds to S2. In S20, the controller 60 reads the field memory 30 and writes the light source light amount in the light amount adjustment circuit 43 based on the value. Further, in S22, the illuminance data for the scanning position of the light source is read from the illuminance distribution data ROM 70, added to the current light amount of the light source, and the necessary gain for the current scanning position is calculated and written in the gain adjusting unit 14. In S23, the light amount adjustment circuit 43 turns on the halogen lamp 40, and the external light and the reflected light from the capture target 10 by the halogen lamp 40 are
In step S24, scanning is performed in the same manner as when irradiating only the external light. In S25, the controller 60 calculates the light receiving time t2 from the sum of the average value of the light amount of the light source and the external light amount, and writes the light receiving time in the light receiving time adjusting unit 18. Then, in S26, the light is received. A light reception signal is output from the CCD 13, and at the same time, in S40, the image reading result of only the external light for the current scanning position is read from the field memory 30 and input to the integrator 76. In S41,
From the controller 60 to the integrator 76, t2 / (A1 · t
1) Double is set, and the image reading result with only external light for the current scanning position is multiplied by t2 / (A1 · t1) and output, and is converted into an analog signal by the D / A converter 17 in S42. And input to the inverting input of the difference amplifier 15. In S44, the outside light and the halogen lamp 4
With respect to the received light signal of the reflected light from the capture target 10 due to 0, only the received light signal of the reflected light from the halogen lamp 40 is amplified by the variable amplification amplifier and input to the A / D converter 16. In S28, the received light signal converted into a digital signal by the A / D converter 16 is input to the integrator 75.
In S29, the controller 60 reads the illuminance data with respect to the scanning position of the light source from the illuminance distribution data ROM 70, and the signal 1 calculates the integrated value for each data and the integrator 75
Is input to In S30, the received light signal output from the integrator 75 is held in the field memory 31. S
If the scanning of the entire area to be taken in 31 is not completed in S31, the processing is continued from S24, and if the scanning is completed, the halogen lamp is turned off in S23. The controller 60 reads the data from the field memory 31, performs image processing such as edge enhancement in S3, and outputs the data to an external output in S4.

In the above embodiment, the received light signal 1 only when external light is incident is stored in the field memory 30 as digital signal data, so that the halogen lamp 40 is turned on when external light is incident. Since a signal obtained by subtracting the received light signal 1 from the received light signal is obtained,
The problem described in can be solved. Further, by setting the gain of the variable gain difference amplifier based on the amount of outside light detected by the photo sensor, the problem described in claim 4 can be solved. Further, by knowing the received light signal 1 and the illuminance data in the illuminance distribution data ROM 70 stored in the field memory 30 and adjusting the light receiving time, the problem described in claim 5 can be solved. Further, the field memory 30 is read out, the sum of the written numerical values is divided by the number of scans, and the average value of the external light illuminance is calculated,
The problem described in claim 6 can be solved by increasing or decreasing the light amount of the halogen lamp based on the value.

[Second Embodiment] FIG. 6 shows an embodiment of the present invention. FIG. 6 is a schematic diagram of the image reading apparatus, which is the same as FIG. 1 except for a part, the same parts are denoted by the same reference numerals, and only the changes will be described below. The change is red LE
A red LED array 140 in which D is arranged two-dimensionally and a green LED array 141 in which green LEDs are arranged two-dimensionally
A blue LED array 142 in which blue LEDs are two-dimensionally arranged, light quantity adjusting units 143, 144, 145, field memories 130, 131, 132, 133, and an image generating circuit 135.

The function of each block in FIG. 6 will be described only as a modification from the first embodiment. The red LED array 140 is controlled by the light amount adjusting unit 143 as a red light source. The green LED array 141 serves as a green light source and serves as a light quantity adjusting unit 14.
Controlled by 4. The blue L array 142 is controlled by the light amount adjusting unit 145 as a red light source. Further, the field memories 130, 131, 132, and 133 respectively receive a received light signal value of only external light, a received light signal calculated value when the red LED array is lit, a received light signal calculation value when the green LED array is lit, and a received light signal when the blue LED array is lit. Save each calculated value within the range to be captured. Image generation circuit 1
Reference numeral 35 generates a color image based on the field memories 131, 132, 133.

FIG. 7 is a main flowchart of the first embodiment,
FIG. 8 shows a flowchart for reading an image when the light source is irradiated.
In FIG. 8, the light source is only replaced with a halogen lamp and an LED array. The flow chart for reading an image only with external light and the flow chart for amplifying the received light signal when illuminating the light source are the same as those in FIGS. The operation of the present embodiment will be described only with respect to the changed portions from the first embodiment according to the flowcharts using FIGS. 6, 7, and 8 described above.

In step S50, the image is read using only external light. The operation at this time is the same as that shown in the first embodiment, and the received light signal 2 only by the external light is transmitted to the field memory 130.
Is stored in Subsequently, in S51, image reading is performed when the red LED is lit. S60 as in the case of the first embodiment
To S62, and in S63, the light source adjustment unit 1
Reference numeral 43 turns on the red LED array 140. Then S6
Steps 4 to S69 are performed in the same manner as in the first embodiment, and the light reception signals integrated in S70 are stored in the field memory 131. If the scanning of the entire area to be captured has not been completed in S71, the process continues from S64, and if the scanning has been completed, the red LED array 140 is turned off in S72.
Similar to the image reading when the red LED array 140 is lit, the light reception signal when the green LED array is lit in S52 is stored in the field memory 132, and the light reception signal when the blue LED array is lit in S53 is stored in the field memory 133. It In S54, the image generation unit 135 adjusts the color balance based on the data stored in the field memories 131, 132, 133 and outputs a color image signal. In S55, the controller 60 performs image processing such as edge enhancement and outputs the result to an external output in S56.

In the above embodiment, the received light signal 2 only in the state where the outside light is incident is stored as the digital signal data in the field memory 130, so that the red LED array 140 and the green LED array in the state where the outside light is incident. 1
41, since a signal obtained by subtracting the light receiving signal 2 from each light receiving signal when the blue LED array 142 is turned on is obtained,
The problem described in claim 2 can be solved.

[Third Embodiment] FIG. 9 shows an embodiment of the present invention. FIG. 9 is a schematic view of the image reading apparatus, and FIGS.
The same parts are indicated by the same numbers except for a part, and only the changes will be described below. The changes are the CCD 213 with color filter and the shift register 29.
0.

The function of each block in FIG. 9 will be described only with respect to changes from the first and second embodiments. C with color filter
The CD is a light-receiving element provided with red, green, and blue color filters alternately, and is alternately output in the order of red, green, and blue. The shift register 290 is for collectively transmitting the received light signal data stored in the field memory 31 in the order of red, green, and blue to the image generation unit 135 when the red, green, and blue data are collected.

FIG. 10 shows a main flowchart of the first embodiment. The flow chart of image reading using only external light and the flow chart of image reading when illuminating the light source are the same as those in FIGS. The operation of this embodiment will be described only with reference to the flowcharts of FIGS. 9 and 10 and only the changed portions from the first and second embodiments.

In S80, the image is read only by the external light. The operation at this time is similar to that shown in the first embodiment, and the received light signal 18 only by the external light is transmitted to the field memory 30.
Is stored in The light reception signal 18 is configured in the order of a light reception signal of light transmitted through the red filter, a light reception signal of light transmitted through the green filter, and a light reception signal of light transmitted through the blue filter. Subsequently, in S81, image reading is performed when the halogen lamp is turned on. The operation at this time is also similar to that shown in the first embodiment, and the received light signal calculation values are alternately arranged in the order of red, green and blue.
Stored in 1. In S82, the field memory 31
The light reception signal data stored in the order of red, green, and blue are input to the shift register 290, and when the red, green, and blue data are complete, are collectively sent to the image generation unit 135 to adjust the color balance. , Is output. In S83, the controller 60 performs image processing such as edge enhancement, and outputs it to an external output in S84.

In the above-described embodiment, the received light is received only when external light is incident, and the received light signal by the light transmitted through the red filter, the received light signal by the light transmitted by the green filter, and the received light signal by the light transmitted by the blue filter are in this order. By storing the received light signal 18 alternately configured as the digital signal data in the field memory 30, the received light signal by the light transmitted through the red filter when the halogen lamp 40 is turned on in the state where the outside light is incident, the green light A signal obtained by subtracting the light reception signal 18 from the light reception signal that is configured alternately in the order of the light reception signal of the light that has passed through the filter and the light reception signal of the light that has passed through the blue filter is obtained, and therefore the problem described in claim 3 is solved. can do.

However, the present invention is not limited to the above Embodiments 1, 2, and 3.

[0038]

【The invention's effect】

[Claim 1] As described in the first embodiment, according to the present invention, when the external light is incident on the object to be read, the received light signal 1 is obtained only when the external light is incident, Obtain the single or multiple received light signals by subtracting the received light signal 1 from the single or multiple received light signals when the single or multiple light sources are turned on with light incident, Since an image is generated in the image, it is effective in removing the influence of the external light on the read image in the environment where the external light is incident.
Further, by considering the illuminance distribution data, it is possible to eliminate the difference in illuminance between the center and the edge of the image, and it is possible to remove the external light more accurately.

[Claim 2] As described in the second embodiment, according to the present invention, when the external light is incident on the object to be read, the received light signal 2 is only when the external light is incident.
And a received light signal 3 when the red light source is turned on with external light incident, a received light signal 4 when the green light source is turned on with external light incident, and an external light incident state The light receiving signal 6 obtained by subtracting the light receiving signal 2 from the light receiving signal 3 and the light receiving signal 7 obtained by subtracting the light receiving signal 2 from the light receiving signal 4 are obtained from the light receiving signal 5 when the light source of
The light-receiving signal 2 is subtracted from the light-receiving signal 8 to obtain a light-receiving signal 8, and a color image is generated based on the light-receiving signals 6, 7, and 8; It is effective in eliminating the effect.

[Claim 3] As described in the third embodiment, according to the present invention, when the external light is incident on the object to be read, the red filter is passed only when the external light is incident. A received light signal 9, a received light signal 10 that has passed through the green filter only when external light is incident, and a received light signal 11 that has passed through the blue filter only when external light has entered,
Light reception signal 12 passing through the green filter when the light source is turned on with external light incident, light reception signal 13 passed through the green filter when the light source is turned on with external light incident, and external light The light reception signal 15 obtained by subtracting the light reception signal 9 from the light reception signal 12 is obtained from the light reception signal 14 that has passed through the blue filter when the light source is turned on when the The signal 16 is obtained, the light reception signal 17 obtained by subtracting the light reception signal 11 from the light reception signal 14 is obtained, and a color image is generated based on the light reception signal 15, the light reception signal 16, and the light reception signal 17, so that external light is incident. It is effective in removing the influence of external light on the read image under the environment.

[Claim 4] As described in the first embodiment, according to the present invention, when the external light or the light amount from the light source changes depending on the reading position, the change is known or detected. Since the gain of the received light signal is adjusted when an image is generated, it is effective in keeping the intensity ratio of the received light signal almost constant in an environment where the illuminance changes within the capture area due to external light or a light source. is there.

[Claim 5] As described in the first embodiment, according to the present invention, when the external light or the light amount from the light source changes depending on the reading position, the light receiving section receives light according to a known change. Since the time is adjusted, it is effective in maintaining the resolution of the received light signal without depending on the dynamic range of the amount of reflected light from the object to be captured by the light source.

[Claim 6] As described in the first embodiment, according to the present invention, a means for detecting the amount of outside light is used when the intensity of outside light increases by using a light source with a constant amount of light. When the amount of external light is large, the amount of light of the light source is also increased, and the amount of light received when only external light is received and the amount of light received when external light is incident on the light source Since it has a means to make the amount of change follow the amount of incident light,
It is effective in maintaining the resolution of the received light signal without depending on the change in the intensity of external light.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an embodiment of an image reading apparatus according to the present invention.

FIG. 2 is a main flowchart of the operation of the image reading apparatus shown in FIG.

3 is a flowchart of image reading using only external light in the operation of the image reading apparatus shown in FIG.

FIG. 4 is an image reading flowchart of the operation of the image reading apparatus shown in FIG. 1 when a light source is irradiated.

5 is a flowchart of light reception signal amplification at the time of light source irradiation in the operation of the image reading apparatus shown in FIG.

FIG. 6 is a schematic view of an embodiment of a color image reading device according to the present invention.

7 is a main flowchart of the operation of the color image reading apparatus shown in FIG.

8 is an image reading flowchart of the operation of the color image reading apparatus shown in FIG. 6 when a light source is irradiated.

FIG. 9 is a schematic view of an embodiment of a color image reading device according to the present invention.

FIG. 10 is an operation main flowchart of the color image reading apparatus shown in FIG.

[Explanation of symbols]

 10 Capture Target 11 Optical System 12 Scanning Motor 13 CCD 14 Gain Adjusting Section 15 Variable Gain Difference Amplifier 16 A / D Converter 17 D / A Converter 18 Light Reception Time Adjusting Section 19 Scanning Adjusting Section 20 Photo Sensor 21 A / D Converter 30 Field memory 31 Field memory 40 Halogen lamp 43 Light intensity adjustment unit 60 Controller 70 Illuminance distribution data ROM 75 Integrator 76 Integrator 80 Document table 130 Field memory 131 Field memory 132 Field memory 133 Field memory 135 Image generation unit 140 Red LED array 141 Blue LED array 142 Green LED array 213 CCD with color filter 290 Shift register

Claims (6)

[Claims] 1. A single or a plurality of light sources, a means for turning on and off the single or a plurality of light sources, and a means for receiving reflected light from a reading object when the single or a plurality of light sources are irradiated. In an image reading apparatus having means for generating an image from the received light, when the external light is incident on the reading target, the received light signal is obtained only when the external light is incident, and the external light is incident. In this state, a single or a plurality of light receiving signals when the single or a plurality of light sources are turned on are obtained by subtracting the light receiving signal from the light receiving signal, and the subtracted light receiving signal and the light source An image reading device characterized by integrating an illuminance distribution and generating an image. 2. The image reading device according to claim 1,
A red light source, a green light source, a blue light source, a means for turning on and off each light source, a means for receiving reflected light from the reading target when the light source is illuminated, and a color image from the received signal. In a color image reading device including a generating unit, when external light is incident on an object to be read, a first light reception signal only when the external light is incident, and a red light source when the external light is incident The second light-receiving signal when the light was turned on, the third light-receiving signal when the green light source was turned on with the outside light incident, and the blue light source was turned on with the outside light incident. From the fourth received light signal, the fifth received light signal obtained by subtracting the first received light signal from the second received light signal is obtained, and the sixth received light signal is obtained by subtracting the first received light signal from the third received light signal. Get the received light signal,
The first light receiving signal is subtracted from the fourth light receiving signal to obtain the seventh light receiving signal, and the fifth light receiving signal, the sixth light receiving signal, the seventh light receiving signal and the illuminance distribution data of each light source are integrated. And a color image reading apparatus characterized by generating a color image. 3. The image reading apparatus according to claim 1,
When the light source, the means for turning on the light source, and the light source are illuminated,
In an image reading device equipped with a means for receiving the reflected light from the object to be read and a means for generating an image from the signal received through each color filter having a red filter, a green filter, and a blue filter on the optical path, the external light is read. When incident on the object, the first received light signal that has passed through the red filter only when external light is incident, the second received signal that has passed through the green filter only when external light has entered, and The third light-receiving signal that has passed through the blue filter only when light is incident, the fourth light-receiving signal that has passed through the green filter when the light source has been turned on while external light has been incident, and the external light is incident. The fifth light-receiving signal that has passed through the green filter when the light source is turned on in the above state, and the sixth light signal that has passed through the blue filter when the light source has been turned on when external light has entered.
From the received light signal of, obtain a seventh received light signal obtained by subtracting the first received light signal from the fourth received light signal, and obtain an eighth received light signal obtained by subtracting the second received light signal from the fifth received light signal. , From the sixth received light signal to the third
A color image reading apparatus, wherein a color image is generated based on the seventh light receiving signal, the eighth light receiving signal, and the ninth light receiving signal by obtaining a ninth light receiving signal obtained by subtracting the light receiving signal of. 4. The image reading apparatus according to any one of claims 1 to 3, wherein the light reception signal is processed as the known light amount or the detected light amount increases in accordance with a known light amount or a change in the detected light amount. An image reading apparatus having a gain adjusting means for reducing the gain at the step of performing the image reading. 5. The image reading device according to any one of claims 1 to 3, further comprising: a light receiving time adjusting unit that reduces the light receiving time of the light receiving unit as the known light amount increases in response to a change in the known light amount. An image reading device characterized by having. 6. The image reading apparatus according to any one of claims 1 to 5, further comprising means for detecting a light quantity of external light, and when the light quantity of the external light is large, the light quantity of the light source is also increased. An image reading apparatus having means for making the amount of change between the amount of received light when only receiving light by itself and the amount of received light when illuminating a light source when external light is incident follow the amount of incident light. .