GB2122048A - Image pickup apparatus - Google Patents
Image pickup apparatus Download PDFInfo
- Publication number
- GB2122048A GB2122048A GB08313173A GB8313173A GB2122048A GB 2122048 A GB2122048 A GB 2122048A GB 08313173 A GB08313173 A GB 08313173A GB 8313173 A GB8313173 A GB 8313173A GB 2122048 A GB2122048 A GB 2122048A
- Authority
- GB
- United Kingdom
- Prior art keywords
- image
- ccd
- photoelectric conversion
- conversion element
- pickup apparatus
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
- H04N1/19—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using multi-element arrays
- H04N1/191—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using multi-element arrays the array comprising a one-dimensional array, or a combination of one-dimensional arrays, or a substantially one-dimensional array, e.g. an array of staggered elements
- H04N1/192—Simultaneously or substantially simultaneously scanning picture elements on one main scanning line
- H04N1/193—Simultaneously or substantially simultaneously scanning picture elements on one main scanning line using electrically scanned linear arrays, e.g. linear CCD arrays
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Facsimile Scanning Arrangements (AREA)
- Image Processing (AREA)
- Facsimile Heads (AREA)
Abstract
An image pickup apparatus comprising a lens for focusing an image picked up from an original, a half-mirror located in the path of light focused by the lens, and a photoelectric conversion element assembly consisting of at least one photoelectric conversion element receiving a transmitted image and at least one photoelectric conversion element receiving a reflected image. The two types of elements are arranged alternately with each other, such that each receives part of the complete original. Thus, even when the original is not placed flat against the image pickup plate, double images do not occur, the images on each element being contiguous. Also, increased resolution of the picked-up image can be obtained at low cost and with simple construction. <IMAGE>
Description
SPECIFICATION
Image pickup apparatus
Background of the invention
Field of the invention
The present invention relates to an image pickup apparatus in a facsimile or copying machine and the like, more particularly to an image pickup apparatus using a plurality of photoelectric conversion elements.
Description of the prior art
Conventional image pickup apparatuses, such as disclosed in Japanese Unexamined Patent
Publication (Kokai) No. 55-48,779, use a plurality of pairs of lenses and photoelectric conversion elements.
Charge-coupled devices (CCD) have commonly been used as the photoelectric conversion elements. CCD's of 2048 bits are now commercially available. Use of a single CCD of 2048 bits for copying a B4 size original (257x364 mm), however, results in a poor image resolution of 8 bits/mm. To increase the resolution, two CCD's of 2048 bits are used. This increases the resolution of B4 size originals to 1 6 bits/mm and the resolution of A3 size originals (297x420 mm) to 13 bits/mm.
Such conventional image pickup apparatuses, however, involve high production costs due to their double CCD construction. More importantly, if the portion of the original corresponding to the connecting portions of the two CCD's is not pressed flat against the glass image-pickup plate, that portion of the original will be picked up as a double image.
This double image phenomenon will be explained with reference to Figs. 1A and 1 B, mentioned in the "brief description of the drawings". In usual cases, an original 4 is placed
in close contact on a glass plate 5. Then, the image in the range of Xa of the original 4 is projected to a photoelectric conversion element 2a through a lens 1 a. At the same time, the image in the range of Xb is projected to a photoelectric conversion element 2b through a lens 2b. Thus, the entire range of the original 4 is picked up using the photoelectric conversion elements 2a and 2b.
As shown in Fig. 1 B, however, if the original 4 is off from the glass plate 5 with spacing Ah, the image of the original 4 in a domain of length As is projected both to the photoelectric conversion element 2b through the lens 1 b and to the photoelectric conversion element 2a through the lens 1 a. Therefore, the domain As isepicked up by both photoelectric conversion elements. Scanning of the photoelectric conversion elements 2a and 2b under this condition results in double images in the domain As of copies obtained from the facsimile or copying machine. The length As in which the double image is picked up is given by the following equation.
As=2 Ah h tan 0 where, 0 is half the angle with which the half
length of the original is viewed at the position of the lens, and Ah is the spacing of the original from the glass plate. Figure 2 shows an example of normal copy on the left side and a double image corresponding to the left side example on the
right side.
Summary of the invention
The object of the present invention is to provide an image pickup apparatus wherein a double image does not occur even when the original is not placed flat against the image pickup plate, and wherein good image resolution is achieved at low cost and with a simple construction.
According to fundamental aspect of the present invention, there is provided an image pickup apparatus, comprising a lens for focusing an image from an original; a half-mirror located at the focused light path of the lens; and a photoelectric conversion element assembly consisting of at least one photoelectric conversion element receiving a transmitted image and at least one photoelectric conversion element receiving a reflected image. The two kinds of photoelectric conversion elements are arranged alternately with each other. The transmitted-image photoelectric conversion element performs photoelectric conversion of an image transmitted through the half-mirror and focused. The reflected-image photoelectric conversion element performs photoelectric conversion of an image reflected by the half-mirror and focused.
Brief description of the drawings
Figures 1 A and 1B show the constitution of a prior art image pickup apparatus;
Fig. 2 is a diagram exp.laining the double image in Fig. 1B; Fig. 3 shows the constitution of an image pickup apparatus according to a first embodiment of the present invention;
Figs. 4A and 4B are diagrams for explaining the embodiment of Fig. 3;
Fig. 5 shows the constitution of an image pickup apparatus according to a second embodiment of the present invention;
Fig. 6 shows the constitution of an image pickup apparatus according to a third embodiment of the present invention;
Fig. 7 is a block circuit diagram of an example of a control circuit in the image pickup apparatus in Fig. 3;
Fig. 8 is a time chart of the circuit in Fig. 7; and
Fig. 9 is an example of an arrangement of image sensors in the apparatus using the control circuit of Fig. 7.
Description of the preferred embodiments
An image pickup apparatus according to a first embodiment of the present invention is explained with reference to Fig. 3, Fig. 4A, and Fig. 4B. In
Fig. 3, reference numeral 1 is a lens, 2a and 2b are photoelectric conversion elements comprising a photoelectric conversion element assembly, 3 is a half-mirror, 4 is an original, 5 is a glass plate on which the original 4 is placed, 6 is a lamp, and 7 is a mirror.
The original 4 is placed on the glass plate 5 with the side to be copied face down. It is Irradiated with light from below by the lamp 6. which is placed so as not to interrupt the light paths and to eliminate shadows appearing at the periphery of a thick original and which usually comprises a pair of lamps or a single lamp and a reflecting plate (not shown). The image reflected from the original 4 is reflected by the mirror 7, then only the image passing through the lens 1 is focused and arrives at the half-mirror 3. The reflection mirror 7 is provided to make the optical system compact and can be omitted if there is sufficient room. The focused image arriving at the halfmirror 3 is divided into transmitted light and reflected light by the half-mirror 3.The OA portion of the original 4 is projected on the O'A' portion of the reflected-image photoelectric conversion element 2a as a real image, while the OB portion of the original 4 is projected on the
O"B portion of the transmitted-light photoelectric conversion element 2b as a real image. In this apparatus, since the points 0' and 0" have an identical common optical axis as clear in Fig. 3, the double image of the conventional apparatus is eliminated. Below, the elimination of the double image is explained in further detail with reference to Figs. 4A and 4B showing the constitution of this embodiment.
In Figs. 4A and 48, the lamp 6 and the
reflection mirror 7 shown in Fig. 3 are omitted.
The half-mirror 3 is located with an appropriate
inclination for the light path (e.g., 45 degrees), the
photoelectric conversion element 2a is located
horizontally (figure shows back face), and the
photoelectric conversion element 2b is located vertically (figure shows upper side). In Fig. 4A, the original 4 is placed on the glass plate 5 in close contact. The image obtained from the photoelectric conversion elements in this state is a
normal image, as shown at the left side of Fig. 2.
In Fig. 4B, similar to Fig. 1 B, the original 4 is placed on the glass plate 5 with a spacing Ah. In this state, since, in the image for the original 4, the optical axis of the portions divided to the two photoelectric conversion elements is common, no
double image portion corresponding to the domain
As of Fig. 1 B appears and a normal image is picked up, as shown in the left side of Fig. 2.
In Fig. 5, the constitution of an image pickup apparatus according to a second embodiment of the present invention is shown. In the apparatus, the objective image is divided into three portions.
Each portion is supplied to one of three photoelectric conversion elements. Therefore, the photoelectric conversion element assembly comprises a transmitted image photoelectric conversion element 2nl and two reflected-image photoelectric conversion elements 2n2 and 2n3:
The transmitted-image photoelectric conversion element and the two reflected-image photoelectric conversion elements are alternately arranged to handle alternate divided portions of the objective image. The other constitutions are similar to the first embodiment.
In Fig. 6, the constitution of an image pickup apparatus according to a third embodiment of the present invention is shown. In the apparatus, the objective image is divided into nine portions, each of which is supplied to one of nine photoelectric conversion elements. The photoelectric conversion element assembly comprises five transmitted-image photoelectric conversion elements 2' 2'n1, 2'n4, 2'n5, 2'n8, and 2'n9 and four reflected-image photoelectric conversion elements 2'n2, 2'n3, 2'n6, and 2'n7. The five transmitted-image photoelectric conversion elements and the four reflected-image photoelectric conversion elements are alternately arranged to handle alternate divided portions of the objective image. The other constitutions are similar to the first embodiment.
Any number of photoelectric conversion elements can be used so the performance of the lens 1 allows. Thus, increased resolution of the picked up image can be achieved with a comparatively simple apparatus. Of course, even in these cases, generation of double images can be eliminated.
Figure 7 is a block circuit diagram of a control circuit of the image pickup apparatus constructed as shown in Fig. 3 and having two CCD image sensors for photoelectric conversion elements.
Figure 8 is a time chart of the control circuit. After receiving an image pickup start signal from a switch on an operation board (not shown) or processor (not shown), a CCD start-stop logic circuit 11 starts to control the image pick-up with a supply of clock pulses from a clock circuit 12. A
CCD-1 control circuit 13 and a CCD-2 control circuit 14 supply several kind of pulses, for example, transmitting pulses, transmitting gate pulses, and reset pulses to the CCD-1 image sensor 2a and the CCD-image sensor 2b at an appropriate timing. These pulses are supplied to the CCD-1 image sensor 2a and the CCD-2 image sensor 2b through CCD drivers included in the
CCD-1 control circuit 1 3 and the CCD-2 control circuit 14, respectively. As a result, the CCD-1 image sensor 2a and the CCD-2 image sensor 2b output video outputs. These two video outputs are sent to an analog switch 21 through a CCD-1 video amplifier 1 5 and a CCD-2 video amplifier 16, a CCD-1 sample-hold circuit 17 and a CCD-2 sample-hold circuit 18, and amplifiers 1 9 and 20, respectively. An analog switch 21 connects the two video outputs from the CCD-1 image sensors 2a and the CCD-2 image sensor 2b for a continuous video signal.
After generation of a line index signal commanding the start of scanning, the CCD-1 control circuit 13 drives the CCD-1 image sensor 2a and, for example, takes out a video output of 2048 bits. After N1 clock pulses are counted, the
CCD-2 control circuit 14 immediately drives the
CCD-2 image sensor 2b and, for example, takes out a video output of 2048 bits, as with the CCD
1- image sensor 2a. After N2 clock pulses are counted, the CCD start-stop logic circuit 11 immediately switches the analog switch 21 to connect the video output from the CCD-1 image sensor 2a with the video output from the CCD-2 image sensor 2b and obtain a continuous video signal of one line.
The CCD-1 image sensor 2a and the CCD-2 image sensor 2b are arranged so that portions of
the video outputs overlap. The arrangement of the two sensors 2a and 2b is shown in Fig. 9. A portion xl on the original 4 forms an image on both anal portion of the CCD-1 image sensor 2a and a b1 portion of the CCD-2 image sensor 2b. A portion x2 on the original 4 forms an image on both an a2 portion of the CCD-1 image sensor 2a and a b2 portion of the CCD-2 image sensor 2b.
As shown in Fig. 3, since the image sensors 2a and 2b are arranged three dimensionally, overlapped image formation is performed, as mentioned above. Also, the video outputs of the hatched portions 31 and 32 in Fig. 8 are eliminated. For example, if both the hatched portions 31 and 32 are 48 bits, the effective video signal in a scanning line is 4000 bits out of 4096 bits. The N 1 is 2048-48x2=1952. N2 is 2000.
If the CCD image sensors 2a and 2b are arranged at appropriate positions by adjusting the positions along the X direction, the eliminated portions 31 and 32 may be 0 bit. Generally, since it is preferable not to require a high accuracy of dimension regarding the distance between an external form of a package and effective elements in the CCD image sensor, so as to increase the production yield, it is desirable that, in a typical design, overlap of the picture signals be adopted and the electrical and mechanical margin corresponding to the difference between N2 and N1 be taken into account.
Although the above-mentioned values are used for simplification of explanation, in practical applications, dummy bits are provided or surplus shift pulses are required by the characteristics of the CCD image sensors. Further details are omitted as they are easily understandable by persons with ordinary skill in the art.
Claims (6)
1. An image pickup apparatus comprising:
a lens for focusing an image picked up from an original;
a half-mirror located at a path of light focused by said lens;
a photoelectric conversion element assembly consisted of at least one photoelectric conversion element receiving a transmitted image and at least one photoelectric conversion element receiving a reflected image, said two types of photoelectric conversion elements being arranged alternately with each other, said transmitted image photoelectric conversion element performing photoelectric conversion of an image
transmitted through said half-mirror and focused,
said reflected-image photoelectric conversion
element performing photoelectric conversion of
an image reflected by said half-mirror and focused.
2. An image pickup apparatus as defined in
claim 1, wherein said photoelectric conversion
element assembly consists of one transmittedimage photoelectric conversion element and one
reflected-image photoelectric conversion element.
3. An image pickup apparatus as defined in
claim 1, wherein said photoelectric conversion element assembly consists of one transmitted
image photoelectric conversion element and two
reflected-image photoelectric conversion elements.
4. An image pickup apparatus as defined in claim 1, wherein said photoelectric conversion element assembly consists of five transmittedimage photoelectric conversion elements and four
reflected-image photoelectric conversion elements.
5. An image pickup apparatus as defined in claim 2, wherein pickup apparatus includes a
CCD-1 image sensor corresponding to said reflected-image photoelectric conversion element, a CCD-2 image sensor corresponding to said transmitted-image photoelectric conversion element, and a control circuit, for controlling said photoelectric conversion elements and for processing the output of said photoelectric conversion elements, comprising:
a clock circuit for generating clock pulses;
CCD start-stop logic circuit receiving an image pickup start signal and clock pulses for controlling the start and stop of image pick-up;
a CCD-1 control circuit receiving the clock pulses and the output of said CCD start-stop logic circuit for supplying control pulses to said CCD-1 image sensor::
a CCD-1 video amplifier for receiving video output from said CCD-1 image sensor;
a CCD-1 sample-hold circuit receiving the output of said CCD-1 video amplifier and the control signal from said CCD-1 control circuit for sampling and holding the sampled video signal;
a CCD-2 control circuit receiving said clock pulses and the output of said CCD start-stop logic circuit for supplying control pulses to said CCD-2 image sensor;
a CCD-2 video amplifier for receiving video output from said CCD-2 image sensor;
a CCD-2 sample hold circuit receiving the output of said CCD-2 video amplifier and the control signal from said CCD-2 control circuit for sampling and holding the sampled video signal; and
an analog switch receiving the video signal from said CCD-1 sample-hold circuit and the video signal from said CCD-2 sample-hold circuit, for connecting the two video signals to a continuous video signal by control of the control signal from said CCD start-stop logic circuit.
6. An image pickup apparatus substantially as hereinbefore described with reference to the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57086318A JPS58202661A (en) | 1982-05-21 | 1982-05-21 | Image pickup device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8313173D0 GB8313173D0 (en) | 1983-06-22 |
| GB2122048A true GB2122048A (en) | 1984-01-04 |
Family
ID=13883480
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08313173A Withdrawn GB2122048A (en) | 1982-05-21 | 1983-05-13 | Image pickup apparatus |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS58202661A (en) |
| DE (1) | DE3318189A1 (en) |
| GB (1) | GB2122048A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2159365A (en) * | 1984-05-23 | 1985-11-27 | Dainippon Screen Mfg | Method for increasing resolution of array sensor and system therefor |
| GB2160058A (en) * | 1984-05-28 | 1985-12-11 | Ricoh Kk | Line image sensor for image processing apparatus |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0614658B2 (en) * | 1985-08-20 | 1994-02-23 | 大日本スクリ−ン製造株式会社 | Image reader |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4005285A (en) * | 1975-10-30 | 1977-01-25 | Xerox Corporation | Optical system for extending photosensor array resolution |
| US4092632A (en) * | 1977-05-02 | 1978-05-30 | Xerox Corporation | Crossover arrangement for multiple scanning arrays |
| EP0019777A1 (en) * | 1979-05-29 | 1980-12-10 | International Business Machines Corporation | Electronically abutting parts of an electronic image produced by linear arrays of photosensitive elements |
-
1982
- 1982-05-21 JP JP57086318A patent/JPS58202661A/en active Pending
-
1983
- 1983-05-13 GB GB08313173A patent/GB2122048A/en not_active Withdrawn
- 1983-05-19 DE DE19833318189 patent/DE3318189A1/en not_active Ceased
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4005285A (en) * | 1975-10-30 | 1977-01-25 | Xerox Corporation | Optical system for extending photosensor array resolution |
| US4092632A (en) * | 1977-05-02 | 1978-05-30 | Xerox Corporation | Crossover arrangement for multiple scanning arrays |
| EP0019777A1 (en) * | 1979-05-29 | 1980-12-10 | International Business Machines Corporation | Electronically abutting parts of an electronic image produced by linear arrays of photosensitive elements |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2159365A (en) * | 1984-05-23 | 1985-11-27 | Dainippon Screen Mfg | Method for increasing resolution of array sensor and system therefor |
| GB2160058A (en) * | 1984-05-28 | 1985-12-11 | Ricoh Kk | Line image sensor for image processing apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3318189A1 (en) | 1983-11-24 |
| JPS58202661A (en) | 1983-11-25 |
| GB8313173D0 (en) | 1983-06-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |