JPH02260762A - Image reader - Google Patents

Abstract

PURPOSE:To suppress the influence of dust or the like upon a reproduced image by forming a solid state image pickup element and a filter integrally in a case body having dust preventing structure and separating the arrangement position of the filter apart from the focus position of an image pickup lens. CONSTITUTION:Respective near infrared ray cutting filters 6 are arranged on positions where the influence of the adhesion of dust does not appear on a reproduced image between respective CCD line sensors 3022, 2023, 3024 and a prism 3021 and these filters 6 and the CCD line sensors 3022, 3023, 3024 form respective units with box-line structure by respective case bodies 9. Thus, the solid state image pickup element such as the CCD line sensor and the filter such as a spectral distribution correcting filter are integrated in the form of a box or a cylinder in the case body with dust preventing structure and the arrangement position of the filter is separated from the focus position of the image pickup lens. Consequently, the influence of dust or the like upon a reproduced image can be removed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image reading device that primarily scans a transparent original such as a 35 mm photographic film to read an image.

[Prior art] Conventionally, CC has a large number of microphotoelectric conversion elements arranged in a light receiving part.
R (red) and G (green) for solid-state image sensors (solid-state image sensors) such as D (charge-coupled devices).

2. Description of the Related Art An image reading device is known that reads an image of a transparent original such as a photographic film using a solid-state color image sensor in which microscopic color separation filters of multiple colors of B (blue) are arranged. In this type of engagement device, generally, as shown in Fig. 2, output corresponding to only visible color rays among the light rays reaching the CCD line sensor 7 is obtained, or each visible light ray is In order to reduce the difference between the respective outputs, a correction filter 6 such as a near-infrared cut filter or a spectral distribution correction filter is provided immediately before the CCD sensor 7. Figure 3 is the CC of Figure 2.
This is an enlarged view of the area around the D line sensor 7.
Here, 8 is a cover glass that protects the CCD line sensor 7.

[Problem to be solved by the invention]

However, in the conventional example described above, by scanning the CCD line sensor 7 or a transparent document (not shown) in the sub-scanning direction, when the image of the transparent document is read by the CCD line sensor 7, the cover glass of the CCD line sensor 7 is If there is dust such as dirt on the 8th side or the 6th side of the correction filter, when the original image is reproduced by a printer, streaky noise will occur in the sub-scanning direction on the reproduced image. However, it has the disadvantage that the image quality (quality) of reproduced images is significantly degraded.

The purpose of the present invention is to eliminate the above-mentioned drawbacks, prevent the adhesion of dust such as dirt, and even if the dust adheres, the original image can be read without being affected by the dust, and the image quality can be improved. An object of the present invention is to provide an image reading device.

[Means to solve the problem]

In order to achieve such an object, the present invention provides a solid-state image sensor that receives transmitted light or reflected light from an original via an IR imaging lens and converts it into an electrical color image signal, and an optical path of the transmitted light or reflected light. The solid-state image sensor and the filter are fixed together, and the solid-state image sensor and the filter are fixed together, and the filter is arranged at a distance from the focal point of the imaging lens so as not to be affected by dust adhesion. The housing has a dustproof structure that prevents dust from entering.

[For production]

In the present invention, a solid-state image sensor such as a CCD line sensor and a filter such as a spectral distribution correction filter are integrated into a box-like or cylindrical shape using a dust-proof housing, and the position of the filter is adjusted to the focal point of the imaging lens. Since it is kept away from the camera, the influence of dust such as dirt on the reproduced image is removed, and the image quality can be improved.

That is, in the present invention, the area between the solid-state image sensor and the solid-state image sensor is completely shielded from the outside by the dust-proof housing, which prevents dust from adhering to the solid-state image sensor. Since the filter is positioned away from the focal point of the filter, even if dust adheres to the surface of the filter, it will have almost no effect on the images reproduced by a printer, etc., making it possible to more faithfully read and reproduce original images such as transparent and transparent originals. can do.

〔Example〕

The present invention will be described in detail below with reference to the drawings.

Figure 1 shows the basic configuration of an embodiment of the present invention. In this figure, 1 is a halogen lamp which is a light source for illuminating the transparent original 4, and 2 is a heat ray absorption filter for removing heat rays from the light rays emitted from the halogen lamp 1. 3 is an illumination optical system (collimator lens) that converts the light beam transmitted through the filter 2 into parallel light beams. The light beam transmitted through this illumination optical system 3 is transmitted through a transparent original 4 such as photographic film,
The light is roughly transmitted through the cover glass 8 of the CCD line sensor 7 that performs photoelectric conversion by the imaging lens 5 and is imaged onto the CCD line sensor 7 . 6 is a near-infrared light cut filter for removing near-infrared light contained in the light beam passing through the imaging lens 5.

The near-infrared light cut filter 6 cuts near-infrared light so that when dust with a diameter of α [+110] or less adheres to the surface of the filter 6, the influence of the dust will hardly appear on the reproduced image. The filter 6 is connected to the imaging lens 5 so that the relationship β>kα is satisfied between the diameter β [mm] of the light beam emitted from the light source 1 on the surface of the filter 6 and the relationship β>kα, where k is a constant.
The CCD line sensor 7 is placed sufficiently far away from the focal point of the sensor 7, with a distance of .degree. C. between the CCD line sensor 7 and the CCD line sensor 7.

Furthermore, the near-infrared light cut filter 6 and the CCD line sensor 7 are fixed in a sealed box-like or cylindrical shape with the near-infrared light cut filter 6 and the CCD line sensor 7 facing each other in a dust-proof housing 9, whereby the near-infrared light cut filter 6 and The gap with the CCD line sensor 7 is sealed to prevent dust such as dirt from entering.

FIG. 4 shows a specific circuit configuration of one embodiment of the present invention.

In this figure, 1 is a light source for illuminating a transparent document (for example, a halogen lamp), 2 is a heat ray absorption filter that removes heat rays from the light rays from the light source 1, and 3 is an illumination optical system that converts the illumination light that has passed through the filter 2 into a parallel beam. It is a system. 3004 is 35mm
A sub-scanning drive table 3005 moves a transparent original 4 such as a photographic film in the sub-scanning direction, a rotary table 3005 rotates the transparent original, and a film holder 3006 stores the transparent original 4.

3008 is a movable mirror that switches the optical path of the light beam (original image) that has passed through the transparent original 4; 3009 is a mirror that deflects the optical path of the original image; and 5 is an imaging lens that forms the original image that has passed through the mirror 3009.

3011 is a projection lens for projecting the original image reflected by the movable mirror 3008; 3012 is a mirror that deflects the optical path; 3013 is a mirror that deflects the same optical path; 3014
is a screen serving as a monitor on which the original image that has passed through the mirror 3013 is projected. 3015 is the screen 3014
3016 is the screen 3
014 is a touch panel that manually controls the trimming area.

3017 is a lamp holding member that supports the light source 1.
3018, 3019, and 3020 are CCD positioning mechanisms, 3021 is a three-color separation prism that separates the transparent original image formed by the imaging lens 5 into three colors of R, G, and B, and 3022, 3023, and 3024 are respectively This is a CCD line sensor using a C0D (charge coupled device) array that photoelectrically converts an original image of each color separated by a prism 3021.

Between the CCD line sensors 3022, 3023, and 3024 and the prism 3021, near-infrared light cut filters 6 shown in FIG. CCD line sensor 3022.3023.3 by each housing 9 in FIG.
024 to form a box-shaped unit.

Also, this CCD line sensor 3022.3023.3
024 is the corresponding CCD alignment mechanism 3018.3019
．． Fine adjustment of the reading position is performed in step 3020. 302
5 is CCD line sensor 3022.3023.3024
3026 is an adjustment signal generation source that generates a standard signal for adjustment to the analog circuit 3025; 3027 is an analog circuit section 3025 3028 is a shading correction circuit that performs shading correction on the output signal of the dark correction circuit 3027; 3029 is the output signal of the shading correction circuit 3028; A pixel shift correction circuit 3030 corrects pixel shift in the main scanning direction, and a pixel shift correction circuit 3030 converts the R, G, and B signals that have passed through the pixel shift correction circuit 3029 to Y (yellow), 1M (magenta), etc. according to the characteristics of the output device. , c (cyan). Further, 3031 is the LOG of the output signal of the color conversion circuit 3030.
Lookup table (LIJT) that performs transformations and γ transformations
It is.

3032 is a minimum value detection circuit that detects the minimum value of the output signal of the lookup table 3031, and 3033 is an under color removal (U(:R)) according to the detected value of the minimum value detection circuit 3032.
Look-up table (LOT) to obtain the control amount for
, 3034 is a masking circuit that performs masking processing on the output signal of the lookup table 3031 based on the detected value of the minimum value detection circuit 3032, and 3035 is a masking circuit that performs masking processing on the output signal of the lookup table 3033 on the output signal of the masking circuit 3034. ucn to perform undercolor removal processing based on
circuit (undercolor removal circuit).

3036 is a density conversion circuit that converts the recording density to a specified density for the output signal of the tlcR circuit 3035, and 3037 is a scaling processing circuit that converts the output signal of the density conversion circuit 3036 to a specified scaling factor. .

3038 is an interface circuit (17F) for transmitting signals between a printer or input/output terminal (not shown) and this device;
3039 is a controller that controls the entire device. The controller 3039 internally includes a CPU (central processing unit) such as a microcomputer, a ROM (read-on memory) in which processing procedures are stored in the form of a program, and a RAM used as a data storage and work area.
(random access memory), etc.

3040 is a peak detection circuit that detects the peak value of the output value inputted from the scaling processing circuit 3037 through the interface circuit 3038 and the controller 3039; 3041 is an operation unit that issues instructions to the controller 3039; 3042
is a display unit that displays the control status of the controller 3039 and the like.

3043 is a lens aperture control unit that controls the aperture of the imaging lens 5, 3044 is a lens distance ring control unit that adjusts the focus of the imaging lens 5, and 3045 is a mirror drive unit that drives the movable mirror 3008. 3046 is a trimming frame control unit that controls the trimming frame display 3015;
47 is a touch panel control unit that controls the touch panel 3016. 3048 is a rotary table rotation control section that drives and controls the rotary table 3005; 3049 is a sub-scanning control section that controls scanning of the sub-scanning drive table 3004; 3050 is a lamp light amount control circuit that controls the light amount of the light source (lamp) 1; 3051 is a lamp position driving source that adjusts the position of the light source 1 via the lamp holding member 3017.

3052 is a timing generator that generates a timing signal (clock) based on the control signal of the controller 3039; 3053 is a bus that connects each of the above-mentioned control units and processing circuits with the controller 3039; 3054 is a data line for output equipment; 3055 is a A synchronization signal line for the output device and 3056 are communication lines.

Next, the operation of each part in FIG. 4 will be explained.

The light source 1 is a light source such as a halogen lamp, and the light emitted from the light source 1 passes through a heat ray absorption film 2 and an illumination optical system 3, and then passes through a 35nm lamp placed on a film holder 3006.
+m A transparent original 4 such as photographic film is illuminated. The image of the transparent original 4 is transferred between the projection lens 3011 and the mirror 3 by switching the optical path by the movable mirror 3008.
012.3013 onto the screen 3014, or ■Mirror 3009, imaging lens 5, and three-color separation prism 3021. CC through the near-infrared light cut filter 6
It is projected onto D line sensors 3022-3024.

In the case of the above operation mode (■), the CCD line sensors 3022 to 3024 are connected to the timing generator 3.
Each CC is driven synchronously by the 052 clock.
The output signal of the D line sensor is input to an analog circuit 3025. The CCD positioning mechanisms 3018-3020 are for registering each CCD line sensor 3022-3024 with respect to the three-color separation prism 3021, and need to perform an adjustment operation at least once. The analog circuit 3025 includes an amplifier and an ADD
(analog/digital) converter, and the signal amplified by the amplifier is sent to the timing generator 30.
A/D conversion is performed by an A/D converter in synchronization with a timing clock for A/D conversion output from 52.

In this way, the dark signal level is corrected by the dark processing circuit 3027 for each of the R, G, and B digital signals output from the analog circuit 3025, and then the shading correction circuit 3028 applies dark signal level correction in the main scanning direction. The pixel shift correction circuit 30 performs shading correction.
At 29, the pixel shift in the main scanning direction is corrected by, for example, shifting the writing timing of a FIFO (first-in, first-out) buffer.

Next, the color conversion circuit 3030 performs color correction on the prism 3021 of the color separation optical system, and converts the R, G, and B signals into Y, M, and C color signals depending on the characteristics of the output device. , or converted into Y, I, and Q color signals. In the next lookup table 3031, by referring to the table, a luminance linear signal can be converted to LOG, or an arbitrary γ
Convert it.

3032 to 3037 are Y, M, C, 8K (black) mainly used for printers such as color laser copiers.
An image processing circuit for outputting an image using four colors is constructed. Here, a minimum value detection circuit 3032, a masking circuit 3034, a lookup table 3033, and an I
The combination of IcR circuit 3035 performs printer masking and OCR (undercolor removal).

Next, the density conversion circuit 3036 performs table conversion of each density signal, and the scaling processing circuit 3037 roughly performs scaling processing in the main scanning direction.
Interface circuit 303 with ° signals to M', C', and B
8 to a printer (not shown) as an output device.

The interface circuit 3038 connects a data line 3054 and a synchronization signal line 3o55 to the output device, such as R5232.
A control command communication line such as C is connected, and a general computer (for example,
It is also possible to communicate with personal computers.

On the other hand, the lamp position drive source 3051 is for adjusting the lamp position when converting the light source lamp 1, and positions the lamp 1 manually or automatically in accordance with the manual key operation on the operation unit 3041. The lamp light amount control section 3050 and the lens aperture control section 3043 are located near the CCD.
1':/Adjusts the amount of received light of the image projected onto the sensors 3022 to 3024. Further, the mirror drive unit 3045 controls the movable mirror 3008 to guide the image of the transparent original 4 to the screen 3014, or directs the image of the transparent original 4 to the screen 3014.
2 to 3024.

In the case of operation mode (3) in which the image of the transparent original 4 is projected onto the screen 3014, the trimming frame display control unit 3046 displays a trimming area to instruct trimming on the screen displayed on the screen 3014. The touch panel controller 3047 controls the touch panel 3016 for inputting the trimming area;
44 controls the focusing ring of the imaging lens 5 to focus images projected on the CCD line sensors 3022 to 3024 and the screen 3014. The adjustment signal generation source 3026 generates a signal manually input as a standard signal when adjusting the analog circuit 3025.

Next, the overall control operation of this apparatus will be explained with reference to the flowchart shown in FIG.

Note that the control procedure in this flowchart is based on the controller 3.
039 is stored in the internal ROM.

Preparation operation: When a power switch (not shown) is turned on, the controller 3039 initializes each part (step S1) and enters a state of waiting for a command input from an external device or from the operation unit 3041 via the interface circuit 3038. In this state, when the film holder 3006 with the transparent original 4 mounted thereon is set on the rotating table 3005, the image of the transparent original 4 illuminated by the light source 1 through the illumination optical system 3 including the heat ray absorption filter 2 and the condenser lens, etc. Movable mirror 3008 and projection lens 30
11 and screen 3 through mirror 3012.3013
014.

Transparent originals 4 have images in vertical and horizontal orientations, but if you want to rotate the image and project it, you can transfer the image from an external device via the interface circuit 3038 or from the operation unit 3041 to the controller 3039. When the rotation of the controller 3039 is instructed (step S9), the controller 3039
sends a rotation control command to the rotary table rotation control unit 3048 via the bus 3053 to rotate the rotary table 3005 (step S3). At this time, the film holder 3
006 is fixed to the rotating table 3005, so the rotating table 3
It rotates with 005. In this way, the transparent original 4
When the image is rotated, the image projected onto the screen 3014 is also rotated.

Next, if you want to trim the image, use the operation section 3041.
or from an external device via the interface circuit 3038 (step s4), the controller 3039 sends a manual command of trimming information to the touch panel control section 3034, and the touch panel control section 3034 displays the trimming information on the touch panel. The trimming information input from 3016 is taken into the controller 3o39 via the bus 3o53, and the controller 3o39 sends trimming frame control information created based on the imported trimming information to the trimming frame display control unit 3046 via the bus 3053. Then, the trimming area is displayed (step S5).

Next, from the operation unit 3041 or the interface circuit 3
When the external device instructs the controller 3o39 to start image reading via 038, image reading starts.
This is carried out according to the following procedure (step S6).

Optical path switching: First, the controller 3o39 outputs a drive control signal to the mirror drive unit 3045 to move the movable mirror 3008, so that the image of the transparent original 4 is transferred to the mirror 300.
9 and the imaging lens 5, the optical path is switched so that it is guided onto each of the CCO line sensors 3022 to 3024 via the three-color prism 3021 (step S7).

Dark correction signal set secondary, dark correction circuit 3027
In order to set the dark correction information to
039, the lamp light amount control circuit 3050 is controlled to turn off the lamp, or the sub-scanning control unit 304
9 to move the sub-scanning drive stand 3004 to a light-shielding position where each CCD line sensor 3022 to 3024 is shielded from light (before step S8). Next, the dark correction circuit 3027 is controlled by the controller 3039, and the dark correction circuit 3027 is controlled based on the signal that is converted into a digital signal and outputted via the analog circuit 3025.
A dark correction signal is set up (after step S8).

AE (automatic exposure adjustment): Next, controller 3039
controls the lamp light amount control circuit 3050 to
, dark correction circuit 3027, shading correction circuit 3028, pixel shift correction circuit 3029, color conversion circuit 3030, lookup table 3031, masking circuit 3034, OCR circuit 3035, density conversion circuit 3
036, the scaling processing circuit 3037 is controlled so that it is all in the through mode (manual data is output as is) (Step S9), and the data input manually to the controller 3039 via the interface circuit 3038 is controlled while performing high-speed sub-scanning. The peak detection circuit 3040 is used to detect a peak on the data (step 5lO), and then the lamp light amount control circuit 3050 is controlled so that the detected peak value approaches a certain level (step 511). The amount of light to the CC line sensors 3022 to 3024 is adjusted by changing the brightness of the light source 1 or by controlling the lens aperture control unit 3043 to change the aperture of the imaging lens 5 (step 512).

8F (autofocus) secondary, dark correction circuit 30
The signal subjected to dark correction by 27 is input to the controller 3039 via the interface circuit 3038 with the subsequent processing circuit set to through mode, and the lens distance rotation control unit 304 uses the information of the input signal.
4 to focus the imaging lens 5 (step 513).

Shading correction data set: Subsequently, each CCD line sensor 3022 to 3024 is 1o09
6. Step 514) of moving the sub-scanning drive base 3004 to the exposure position where exposure is to be performed. The lamp light amount control circuit 3050 adjusts the lamp light amount to an appropriate brightness, and the dark correction circuit 3
The shading correction data is set in the shading correction circuit 3028 while inputting the signal subjected to the dark correction in step 027 (step 515).

After selection, the pixel shift correction amount is set in the pixel shift correction circuit 3029 (step 516), and the color conversion circuit 3
Select the type of color conversion for 030, select the type of lookup table for lookup tables 3031 and 3033, select the type of masking for masking circuit 3034, and select IIc for LIGR circuit 3035.
The presence or absence of R is selected, the type of density conversion is selected for the density conversion circuit 3036, and the scaling,
The type of sharpness is selected (step S1?), and further, the light intensity of the lamp 1 is controlled to be appropriate via the lamp light intensity control circuit 3035, and the sub-scanning control section 3049
sends the sub-scanning speed and trimming information to move the transparent original 4 to the sub-scanning start position and wait (step 518).
.

Data output A: In an operation based on a read start command from the operation unit 3041 (step 519), a start command is issued to an output device (not shown) via the interface circuit 3038 (step 520), based on a synchronization signal from the output device. Then, sub-scanning is started (step 522), the image is captured while being synchronized with the output device, and the processed image data is outputted via the interface circuit 3038 (step 523).

Data output B: In the reading operation based on the reading start command via the interface circuit 3038 (step 519
), the completion of preparation is reported to the output device (not shown) via the interface circuit 3038 (step 521),
Based on the synchronization signal from the output device, sub-scanning is started (Step 522), the image is captured while being synchronized with the output device, and the processed image data is sent to the interface circuit 3038.
(step 523).

B. Example 2 FIG. 6 shows a circuit configuration of another embodiment 2 of the present invention.

In this figure, 3059 is the pixel shift correction circuit 3 of FIG.
029 is a corresponding buffer memory, 3061 is a CCD line sensor with an R color separation filter, 3062 is a CCD line sensor with a G color separation filter, 3063
is a CCD line sensor with a B color separation filter. In addition, 3064 is a CCD line sensor 3061 to 3.
CCO positioning mechanism for positioning 063, 30
65-3067 are CCD line sensors 3061-30I
Timing generator 3 (
153b). The rest of the structure is the same as that of the previous embodiment shown in FIG.

The solid-state image sensor 7 is a 3-line line sensor 3061 to 3.
063, each line sensor 3061 to 306
3 are independently driven by drive signals 3065 to 3067 output from a timing generator 3052.

Furthermore, each of the line sensors 3061 to 3063 is capable of capturing R, G, and B color-separated images using respective color filters.

The buffer memory 3059 stores each line sensor 3061 to 3.
This is a delay memory for correcting positional deviation in the sub-scanning direction in 063, and is configured using, for example, several FIFO memories. The amount of delay for each color is controller 3
039 in advance according to the sub-scanning speed.

FIG. 7 shows a cross-sectional structure of the CG[l line sensor portion of FIG. 6. As shown in FIG. 7, in this embodiment, the cover glass of the CCI line sensor 7 is removed, and a near-infrared light cut filter 6 is used as the cover glass. The near-infrared light cut filter 6 is placed at a sufficient distance 1111 from the CCD sensor 7 so that even if dust adheres to the filter surface, it will not affect the reproduced image by a printer or the like.

In addition, in the first embodiment shown in FIG. 1 described above, the near-infrared light cut filter 6 and the CCD line sensor 7 face each other by the housing 9, and have a sealed box-like structure. The casing 9 forming the structure does not have to be a plate-like body, and there is no problem even if it is made of a member that does not allow dust to pass through, such as a dust filter.

(Effects of the Invention) As explained above, according to the present invention, a solid-state image sensor such as a CCD line sensor and a filter such as a spectral distribution correction filter are integrated into a box-like or cylindrical shape using a dust-proof housing. , and the filter is arranged at a distance from the focal point of the imaging lens, so that the influence of dust particles on the reproduced image is eliminated, and the image quality is improved.

That is, in the present invention, the area between the solid-state image sensor and the solid-state image sensor is completely shielded from the outside by the dust-proof housing, which prevents dust from adhering to the solid-state image sensor. Since the filter is positioned away from the focal point of the filter, even if dust adheres to the surface of the filter, the effect of the dust will hardly appear on the image reproduced by a printer, etc., making it possible to more faithfully read and reproduce original images such as transparent originals. This has the effect of being able to.

[Brief explanation of drawings]

Figure 1 is a layout diagram showing the basic configuration of an embodiment of the present invention, Figure 2 is a layout diagram showing an example of the configuration of a conventional image reading device, and Figure 3 is an enlarged view of the area around the CCD line sensor in Figure 2. FIG. 4 is a block diagram showing a specific circuit configuration of the first embodiment of the present invention, FIG. 5 is a flowchart showing the operation procedure of the embodiment of the present invention shown in FIG. 4, and FIG. A block diagram showing the circuit configuration of another embodiment 2 of the present invention. FIG. 7 is a sectional view showing the sectional configuration of the portion shown in FIG. 6. DESCRIPTION OF SYMBOLS 1... Light source, 2... Heat ray absorption filter, 3... Illumination optical system, 4... Transparent original, 5... Imaging lens, 6... Near-infrared light cut filter, 7... - CCD line sensor, 8... cover glass, 9... housing. Dog - X Jin Figure 7

Claims (1)

[Scope of Claims] 1) A solid-state image sensor that receives transmitted light or reflected light from an original via an imaging lens and converts it into an electrical color image signal; a filter that is arranged and whose arrangement position is away from the focal position of the imaging lens so as not to be affected by the adhesion of dust; and the solid-state imaging device and the filter are fixed together, and the solid-state imaging device and the filter are fixed together. An image reading device comprising: a casing having a dustproof structure that prevents dust from entering between the filters; 2) The image reading device according to claim 1, wherein the filter is a near-infrared light cut filter or a spectral distribution correction filter.