JPH0795363A - Picture reader - Google Patents

Abstract

PURPOSE:To prevent missing of a picture area and an output of picture data in an undesired area by improving the precision of detection of an end of an original almost without increase in the processing time of the entire reading. CONSTITUTION:The reader is made up of a line sensor 22, scanning systems 26, 90, 95 scanning an original picture with relative movement between the line sensor 22 and the original picture and a CPU 91 which varies a ratio of a moving quantity of a scanning system to a sampling frequency of the line sensor 22 between a scanning area of the scanning system corresponding to a closely approached part of an original picture end and other area, detects a difference of an output signal of the line sensor 22 between an inner area and an outer area of an original picture to recognize a scanning position equivalent to the original picture end. That is, the scanning speed is reduced or the sampling frequency is increased in the scanning moving area for the detection of the end of the original picture after automatic focus control.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus, and in particular, it reads image information as an electric signal by scanning a plurality of linear photoelectric conversion elements relative to an optically formed image. The present invention relates to an image reading device.

The apparatus of the present invention can also be applied as an applied device to an image scanner for a reflective original or a transparent original, or an image reading unit for a copying machine or a facsimile.

[0003]

2. Description of the Related Art Conventionally, as an image reading apparatus of this type, for example, a plurality of light receiving elements arranged in a line form an image obtained by forming reflected light of an original image or an image obtained by forming transmitted light of an original film. There is known an image reading device for reading with a line sensor such as a CCD having a line. This image reading device sequentially electrically scans and outputs the detection data of the light receiving element corresponding to each pixel in the line direction of the line sensor, and in the lateral direction, the mechanical data between the original image and the line sensor. By mechanically scanning and moving by the dynamic scanning system, 2
It is configured to obtain dimensional image information.

In the external data processing device connected to the output side of such an image reading device, it is specified to output the image data of the entire region from one end to the other end of the image region to be read without excess or deficiency. In this case, the control system of the data processing device is to grasp the correspondence between the position of the end of the image area and the scanning movement position of the mechanical scanning system.

Further, when the positional accuracy of the image area to be read is particularly required, an image reading apparatus is provided which performs a detecting operation for detecting the position of the document edge as a preliminary operation before the regular image reading operation. There is. This device, for example, when a stepping motor is used as the drive source of the mechanical scanning system, the characteristic difference between the image data inside the image area and outside the image area while the image is scanned by the movement of the scanning system once. When it is extracted, it is determined that it is the document end, and the cumulative number of drive pulses from the home position of the stepping motor at this time is stored in the memory.
At the time of the next regular image reading scan, control is performed so that the output of the image data is started or the output of the image data is ended when the accumulated value of the drive pulses of the stepping motor reaches the accumulated drive pulse number. There is.

In particular, when the original is a film loaded in the slide mount, there are many variations in the outer dimensions of the slide mount and the opening size of the aperture portion, and therefore the original (film) is supported by a method of supporting the slide mount from the outside. When is set, it is difficult to secure the scanning position accuracy for the actual image portion to be read. Therefore, the detection operation for detecting the position of the document edge as described above is performed as a preliminary operation before the normal image reading operation.

[0007]

However, in the conventional apparatus as described above, it is generally required that the preliminary operation as described above be processed in a short time. In order to meet this requirement, the moving speed of the scanning system is to be met. If the edge of the image is detected at a high speed, the amount of movement of the scanning system with respect to the sampling interval time of the line sensor becomes large, and thus the resolution of detecting the position of the edge of the document is lowered. For this reason, the conventional device cannot completely prevent the image area to be read from being missing or the image data from being output in an unnecessary area. In particular, when the original is a film, the read image data is often enlarged and printed out, so that the position error in the reading range is very noticeable.

On the contrary, if the moving speed of the scanning system in the document edge detection area is slowed by giving priority to the detection resolution,
This preparatory operation takes time, which increases the processing time of the entire reading operation.

In view of the above-mentioned problems, an object of the present invention is to improve the accuracy of document edge detection without increasing the processing time of the entire reading operation, and to eliminate image areas and unnecessary areas. An object of the present invention is to provide an image reading device that prevents the output of image data.

[0010]

In order to achieve the above object, the present invention provides a photoelectric conversion means for reading an original image in which light receiving elements are linearly arranged, and the relative photoelectric conversion means and the original image. Output means of the photoelectric conversion means between the scanning means for scanning the original image by the automatic movement and the scanning area of the scanning means and the other scanning area corresponding to the vicinity of the edge of the original image. The end portion of the original image is detected by changing the ratio of the moving amount of the scanning unit to the time and detecting the difference in the output signal of the photoelectric conversion unit between the inner area side and the outer area side of the original image. And a control unit for recognizing the scanning position corresponding to.

In a preferred aspect of the present invention, the control means has a moving speed of the scanning means between a scanning area of the scanning means and another scanning area corresponding to a proximity portion of an end portion of the original image. Is variable.

As another aspect of the present invention, preferably, the control means includes the photoelectric conversion means between a scanning area of the scanning means and another scanning area corresponding to a proximity portion of an end portion of the original image. The output signal extraction interval time is variable.

As another aspect of the present invention, preferably, the control means further comprises detection means for detecting information relating to the vertical and horizontal directions of the original image or the size of the original image, and the control means includes detection information of the detection means. The scanning movement region in which the ratio of the movement amount of the scanning unit to the output signal extraction interval time of the photoelectric conversion unit changes is changed according to the above.

Further, the present invention preferably further has an auto-focusing means for automatically focusing and focusing the image light from the original image on the light receiving element of the photoelectric conversion means. The control means recognizes a scanning position corresponding to an end portion of the document image after the operation of the automatic focusing means is performed.

As another aspect of the present invention, preferably, the apparatus further comprises a document illuminating means for varying the amount of illumination light to the original, and the control means changes the output signal extraction interval time of the photoelectric conversion means. It is characterized in that the change of the illumination light amount is synchronized.

[0016]

With the above structure, the image reading apparatus of the present invention has the sampling interval time (output signal extraction interval time) of the line sensor (light receiving element) within the detection scanning area at the document edge.
The amount of movement of the scanning system (scanning means) with respect to is reduced, which increases the detection resolution of the document edge position,
The detection accuracy is improved. By referring to this detection data at the time of the next regular image reading scan and outputting the image data,
It is possible to effectively prevent the loss of the image area and the output of the image data of the unnecessary area, which have occurred in the related art as described above.

The operating range for finely adjusting the movement amount of the scanning system with respect to the sampling interval time of the line sensor is
Since it is limited to the detection scanning area in the vicinity of the document edge, it is possible to minimize the time loss related to the document edge detection operation, and prevent an increase in the processing time of the entire reading operation.

[0018]

Embodiments of the present invention will now be described in detail with reference to the drawings.

(First Embodiment) FIG. 1 shows the structure of a reading mechanism of an image reading apparatus according to the first embodiment of the present invention. The apparatus of this example is an image reading apparatus for a film original having a scanning system for scanning an image by moving a line sensor.

The light-transmitting original films 1a, 1b, 1c and 1d shown in the exploded perspective view of FIG. 1 (general number 1)
Are slide mounts 2a, 2b, 2c and 2d, respectively.
It is loaded and protected (general number is 2).
The film carriers 6 and 7 sandwich and support the respective original films 1 via the respective slide mounts 2. After the original films 1 are sandwiched, the film carriers 6 and 7 are joined to each other and integrally inserted into the apparatus main body. It is operable. Further, the film carriers 6 and 7 are provided with an opening at a position corresponding to the position of each original film 1, so that irradiation light from one direction can pass through the original film 1 and then be emitted in another direction. Has become. Further, the film carriers 6 and 7 may be inserted into the main body of the apparatus with the longitudinal direction thereof oriented in the Y direction as shown by the solid line in FIG. As shown in
It is also possible to insert it with its longitudinal direction facing the X direction. At the position directly below the arrow A, the film carriers 6, 7 or 6 ', which are separately inserted from both directions,
The original film 1 sandwiched by 7'is positioned in the same plane and in such a positional relationship that the film centers intersect at the same position.

An arrow A ₀ indicates the direction of incidence of illumination light from an illumination means (not shown) for illuminating the original film 1. At the position immediately below the arrow A ₀ , the arrow Y direction or the arrow X
The original film 1 (1c in the figure) in the film carriers 6, 7 (or 6 ', 7') inserted from the direction is illuminated. By changing the inserting direction of the film carrier, the reading direction of the original film 1 can be switched at the same original setting position.

The image forming lens 10 is for forming an image of the original film 1c on a line sensor 22 described later. The orientation of the image formed by the imaging lens 10 is as shown by reference numerals 8 and 9. When the longitudinal direction of the original film 1 is the Y direction at the original setting position, the projection image 8 is formed, and the original film is formed. When the longitudinal direction of 1 is the X direction, the projected image 9 is formed. The imaging lens 10 is held by a holding mechanism (not shown) so as to be movable in the Z direction (optical axis direction), and can be moved integrally with a pin 11 fixed to the lens barrel.

The lens lever 12 can be swung about a swing shaft 13 fixed to the main body of the apparatus, and the pin 11 is inserted into an elongated hole opened on the left side of the lens lever 12 on the other side. The action surface 12a is formed by being bent in the horizontal direction.

The lens drive motor 14 is arranged on the lower rear side of the lens lever 12, and an eccentric cam 15 is fixed to the output rotation shaft 14a thereof. The eccentric cam 15 has a shape capable of making contact with the lever acting surface 12a of the lens lever 12, and the lever acting surface 12a is displaced by the eccentric shape as the lens driving motor 14 rotates. Due to this displacement, the lens lever 12 swings up and down about the swing shaft 13, whereby the imaging lens 10 can be moved up and down via the pin 11. The lens drive motor 14 is configured by a stepping motor (also referred to as a pulse motor), and has a main body CPU 91 (see FIG. 2) described later.
The rotation amount is generated in accordance with the number of drive synchronization pulses from (see).

The drive base 30 has a box-shaped auxiliary drive plate 3 having a surface 39a parallel to the drive base 30 on the back side thereof.
9 is integrally fixed. Surface 39 of drive assist plate 39
The drive shaft 33 is rotatably supported by a and the drive base 30 via a bearing (not shown). A wire pulley 34 is fixed to the front end of the drive shaft 33, and a large pulley 3 for a timing belt is attached to the rear end thereof.
5 is fixed. The scanning motor 26 is a driving auxiliary plate 39.
Is fixed to the surface 39a. The output shaft 28 of the scanning motor 26 projects rearward from the drive assisting plate 39,
A small pulley 29 for a timing belt is fixed to the end of 8. The scanning motor 26 is configured by a stepping motor, and produces a rotation amount according to the number of drive synchronization pulses from a scanning CPU 90 (see FIG. 2) described later.

The timing belt 36 is wound around the small pulley 29 and the large pulley 35, and transmits the rotational force of the scanning motor 26 to the drive shaft 33. A pair of driven pulleys 31 and 32 are rotatably supported at left and right upper portions of the drive base 30, and a wire 37 wound around a wire pulley 34 integrated with the drive shaft 33 is wound around the driven pulleys 31 and 32. ing. The moving direction of the wire 37 is changed by switching the rotating direction of the wire pulley 34.

The terminal 37a at the right end of the wire 37 is hooked on the right hook of the movable locking plate 38, and the terminal 37b at the left end of the wire 37 is connected to the locking plate 38 via a tension spring 40. It is hooked on the left side hook part.
The wire 37 is tensioned by a tension spring 40 with an appropriate tension to form a closed loop.

On the other hand, the sensor unit 20 is attached to the upper surface of the sensor support 21. A line sensor 22 is mounted on the sensor unit 20, and the light-receiving surface of the sensor faces upward. The image of the original is optically formed directly above the sensor support 21,
The pair of scanning rails 25 and 26 are arranged at positions corresponding to this image formation and fixed to the apparatus main body.

A sensor driver substrate 92 (see FIG. 2), which will be described later, is arranged inside the sensor support 21, and the sensor unit 20 is driven and image data is taken in through this substrate. The image data in each line direction (Y direction) of the line sensor 22 is the sensor driver board 92.
Are sequentially read out for each pixel in accordance with the synchronization signal. At the same time, two-dimensional image data is obtained via the sensor driver board 92 by mechanical scanning in the X direction of the sensor support 21 that is guided and moved by the scanning rails 25 and 26.

The locking portion 21a fixed to the front surface of the sensor support 21 is inserted into the screw plate 38a by passing a screw (not shown) into the screw hole 38a at a position overlapping the upper surface of the movable locking plate 38. It is fixed so that the drive system and the sensor system are connected. That is, the rotation of the scanning motor 26 depends on the pulley 2
It is converted into horizontal movement of the locking plate 38 attached to the wire 37 via 9, 35, etc., whereby the sensor support 21 moves in the X direction via the locking portion 21a.

Document direction switches 4 and 5 are arranged in an operation section (not shown) of the apparatus main body. The manuscript direction switches 4 and 5 transmit information regarding the direction of the manuscript film 1 to the control system by being pressed by the operator depending on the direction of the manuscript film 1. In this example, if the operator presses the original document direction switch 4 when the longitudinal direction of the original film 1 is the Y direction and the original document direction switch 5 when the longitudinal direction of the original film 1 is the X direction, the control system causes the original film film at this time. The direction of 1 will be recognized. It should be noted that it is also possible to automate by disposing a micro switch instead of the switches 4 and 5 in the insertion path of the film carriers 6 and 7.

FIG. 2 shows the configuration of the control system in this embodiment.

The sensor driver 92 is a main body CPU
(Central processing unit) The line sensor 22 is driven according to the sampling synchronization signal supplied from 91, and the line data (line image data) from the line sensor 22 is driven.
To extract. The data of each pixel arranged in one line of the line sensor 22 is sampled all at once by a line data sampling synchronization signal having a cycle corresponding to the storage time during photoelectric conversion. Further, each pixel data in the sampled line is sequentially extracted according to the main scanning synchronization signal of the sensor driver 92 and transferred to the image processing unit 99 through the sensor driver 92.

The illumination lamp 19 illuminates the original film 1 in the direction of arrow A _{0 with} respect to the original setting position in FIG. 1, and its power is supplied from the illumination power source 94. The illumination power supply 94 receives a command from the CPU 91 of the main body, and the illumination lamp 1
9 is turned on and off.

The original direction switches 4 and 5 are respectively O
Information regarding the direction of the original film 1 is transmitted to the main body CPU 91 depending on the N or OFF state.

The lens drive motor driver 93 is a main body C
The motor drive synchronization signal is supplied from the PU 91, and the excitation circuit of the lens drive motor 14 is driven so that the rotation amount of the motor has a one-to-one correspondence in accordance with the motor drive synchronization signal. The lens driving motor 14 moves the imaging lens 10 in the Z direction by the rotation operation thereof so that the projection image of the original film 1 is focused on the light receiving surface of the line sensor 22. The operation procedure of the motor 14 will be described later with reference to FIG.

The scanning CPU 90 communicates with the main body CPU 91 to determine the start and stop timings or rotational positions of the scanning motor 26 and the drive synchronization pulse supply pattern during acceleration / deceleration or constant speed driving. The drive synchronization pulse is transmitted to the scan motor driver 95 with the determined supply pattern. An operation program of the scan CPU 90 shown in FIG. 4 and the like is stored in the ROM 88 in advance, and
It is sequentially read by 90. Further, the parameters and the like necessary for the calculation for the above determination are stored in the RAM 89 in advance. The scan motor driver 95 receives a motor drive synchronization signal from the scan CPU 90, and drives the excitation circuit of the scan motor 26 so that the rotation amount of the motor corresponds to the motor drive synchronization signal in a one-to-one correspondence.

The image processing unit 99 corrects or supplements the image data extracted by the line sensor 22 and processes it into data desired by the operator. The processed image data is transferred to the interface 96 based on a command from the main body CPU 91.

The interface 96 is an external data processing device 5 connected to the output side of the latter stage of the image reading device.
00, data relating to the read image area and control signals such as a scan start signal or a scan end signal are exchanged, these data and signals are transmitted to the main body CPU 91, and the image data from the image processing unit 99 is transferred to external data Output to the processing device 500.

The main body CPU 91 controls the operation of each of the above functional blocks while taking timing. The operation program is stored in advance in the ROM 97, and the main body CPU 91 executes the control operation while sequentially reading the program during operation. Further, the main body CPU 91 also executes the calculation for the automatic focusing operation, which will be described later, and the calculation for the document edge recognition based on the image data extracted from the line sensor 22.

The RAM 98 stores variables necessary for the above-mentioned control of the main body CPU 91, results of operations, image data created by the image processing unit 99, and the like. The stored data and the like are read out to the main body CPU 91 as needed.

FIG. 3 is a diagram showing the relationship between the setting direction of the original film 1 and the scanning speed in the above embodiment. FIG. 3A shows the projected images 8 and 9 to be read corresponding to the setting direction of the original film 1. Indicates range and direction. The end of each projected image corresponds to the opening end of the aperture of the slide mount 2 on which the original film 1 is loaded. The image edges 8a and 9a indicate image edges on the home position side of the sensor support 21, and the image edges 8b and 9b indicate image edges on the opposite side of the edge portions 8a and 9a.

FIG. 3B shows the relationship between the scanning position coordinates of the line sensor 22 and the scanning speed during the document edge detection operation of the projected image 8, and the abscissa is the scanning position of FIG. 3A. It is equivalent to the coordinates.

FIG. 3C shows the relationship between the scanning position coordinates of the line sensor 22 and the scanning speed during the document edge detection operation of the projected image 9, and the abscissa is the scanning position of FIG. It is equivalent to the coordinates.

In this embodiment, the operation procedure from the mounting of the original film 1 to the detection of the original edge is as follows.

(1) First, the operator first inserts the film carriers 6 and 7 holding the original film 1 into the apparatus main body, and turns on the original direction switch 4 or 5 depending on the setting direction of the original film 1.

(2) The main body CPU 91 receives the signals from the document direction switches 4 and 5 and activates the illumination power supply 94 to turn on the illumination lamp 17 to illuminate the film document 1. As a result, the projected image of the original film 1 is transferred to the line sensor 22.
Is formed on the scanning surface of.

(3) Next, the scanning CPU 90 activates the scanning motor driver 95 to start scanning movement for detecting the document edge. Here, the scanning drive pattern shown in FIG. 3B is executed when the document direction switch 4 is ON, and the scanning drive pattern shown in FIG. 3C is executed when the document direction switch 5 is ON. Run.

The following (4) to (6) are operations in the pattern shown in FIG. 3B when the document direction switch 4 is ON, that is, when the longitudinal direction of the document film 1 is the Y direction. It describes the procedure.

(4) The sensor support 21, which was initially located at the first home position P ₀ outside the projection image area, is subjected to a series of acceleration, high-speed steady speed v ₁ and deceleration driving due to the autofocus operation, and the line The sensor 22 displays the central position P _{3 of the} projected image.
To be moved to.

This is because when the original is a film as in this example, the thickness of the slide mount varies greatly, the projected image on the line sensor is out of focus, and the optical resolution is lowered. This is because the automatic focusing operation is first required before the accurate image edge detection is performed.

(5) The operating principle of the automatic focusing is that the amount of contrast between adjacent pixels on the line is calculated from the line data extracted at every predetermined rotation angle during one rotation of the lens drive motor 14, and each of them is calculated. The point where the contrast amount at each rotation angle becomes the maximum value is the in-focus point. The main body CPU 91 sets the number of drive synchronization pulses corresponding to the rotation angle position of the lens drive motor 14 when it is determined to be the in-focus point to R
Once stored in the AM 98, the rotation is stopped at the time when this rotation position is reached in the rotation operation of the next cycle, and the position is held. This makes it possible to obtain a projected image that is accurately focused on the scanning surface of the line sensor 22, and secures the optical resolution necessary for detecting the document edge.

(6) After the automatic focusing operation, the sensor support 21 is driven again at high speed to move to the document edge detection area. If the position of the document edge predicted to shift due to an actual error is within the range of scanning positions P _{6 to} P ₇ with respect to the logical nominal position of the document edge 8 b on the projected image, scanning is performed within this range. The moving speed is changed to the low speed v ₂ . The actual scanning movement speed decelerates from the position P ₅ which is in front of the falling distance required for deceleration from the high speed scanning movement speed v ₁ to the low speed image edge detection speed v ₂ .

The flowchart of FIG. 4 shows an example of the operation sequence of the scan CPU 90 relating to the document edge determination and detection in this embodiment.

In step 101 and step 102, in order to control the movement of the sensor support 21, the drive synchronization signal to the scan motor driver 95 issued from the scan CPU 90 is counted up by the scan CPU 90. As a result, the cumulative count number C _N from when the sensor support 21 is at the first home position is the scan CPU.
It is stored in the count register in 90.

In the next step 103, the line sensor 2
Whether or not the second scanning position has reached the point P ₆ is determined by the cumulative count number C _N of the scanning motor drive synchronization signal. Count C _N of the scan motor drive synchronization signal necessary for the scanning position reaches the point P ₆ can be calculated from the scan amount of one pulse corresponding to the scan motor drive synchronization signal, when the value and N _6, actual If the count number C _N does not reach this value N ₆ , the process returns to step 101 to continue counting up the scanning motor drive synchronization signal, and when the actual count number C _N reaches N ₆ , the process proceeds to the next step 104.

In step 104, the scanning CPU 90 reduces the frequency of the drive synchronization signal of the scanning motor 26 in order to reduce the scanning speed to v ₂ .

FIG. 5 shows the relationship between the line data sampling sync signal and the scan motor drive sync signal, which is shown in FIG.
Shows the relationship between the line data sampling sync signal and the scan motor drive sync signal in the normal state, and FIG.
Shows the relationship between the line data sampling synchronization signal and the scan motor drive synchronization signal in the document edge detection operation area.
The example of the timing chart of FIG. 5 shows that the scanning system moves in the X direction by a distance corresponding to one line width every time 6 pulses of the scanning motor drive synchronization signal are input.
Normally, as shown in FIG. 5A, the line data is sampled once by the movement of 6 pulses of the scanning motor drive synchronization signal, but in the document edge detection operation area, the line data shown in FIG. ), Line data is sampled twice by the movement of 6 pulses of the scanning motor drive synchronization signal. Therefore, at the time of detecting the document edge, twice the detection resolution can be obtained for the same movement amount of the scanning system.

In step 105, the scanning CPU 90 stores the sampling data of the line sensor 22 as an initial value in the address M ₁ portion in the RAM 98 via the main body CPU 91 and secures it as comparison data for later document edge detection.

In steps 106 and 107, the scan CPU 90 increments the drive synchronization signal of the scan motor 95 by 1 as in steps 101 and 102 described above. As a result, the cumulative count number C _N from the home position of the sensor support 21 is stored in the count register in the scan CPU 90. The value of the cumulative count number C _N is also transmitted to the main body CPU 91 and is used as a reference by the main body CPU 91 as a variable corresponding to the position coordinate of the document edge.

In step 108, the scanning CPU 90 sends the sampling data at the current scanning position of the line sensor 22 to the address M ₂ in the RAM 98 via the main body CPU 91.
To be stored in the department.

In step 109, the scan CPU 90 contents the address M ₂ which is the current sampling data and the contents of the address M ₁ which is the data sampled one pulse before the scan motor drive synchronizing signal with respect to the current scanning position. Are compared to determine whether or not the document edge has been reached. Since the detected light amount is obviously different between the region where the transmitted light of the original film 1 is projected and the region where the illumination light is shielded by the outside of the aperture frame of the aperture of the slide mount 2, the difference in the detected light amount is taken as the difference of the sampling data. If detected, it can be determined whether or not the document edge has been reached. If the document edge is not recognized, the process proceeds to step 110, and if it is recognized as the document edge, the process proceeds to step 113.

In step 110, the scan CPU 90 determines whether the scan position is within the detection range of the document edge or has deviated from the pulse count number C _N of the motor drive synchronization signal. Assuming that the count number of the scan motor drive synchronization signal required for the scanning position to reach the point P ₇ is N ₇ , if the actual count pulse number C _N exceeds N ₇ , the document edge cannot be recognized. Since it has reached the outside of the scheduled area for detection scanning, the routine proceeds to step 111, where a warning display or the like is performed as an error operation.

The actual count pulse number C _N is N ₇
If it has not reached, the process proceeds to step 112 and the content of the address M ₂ which is the sampling data of the line sensor 22 at this time is stored in the address M ₁ in the RAM 98 via the main body CPU 91. Is stored by transfer and the contents of address M ₁ are updated,
Prepare as comparison data for the next document edge recognition.
Then, the process returns to step 106. This operational loop is repeated until the document edge is recognized in step 109. When the document edge is recognized, the process proceeds to step 113.

In step 113, the scanning CPU 90 stores the count number C _N of the scanning motor drive synchronization signal when the document edge is recognized in the register X _b in the main body CPU 91 via the main body CPU 91. The contents of this register _Xb correspond to the scanning position of the projected image end 8b.

In the next step 114, the scanning CPU 90
Scans the line sensor 22 to the second home position P ₁₀ which is symmetrical to the first home position with respect to the center of the image.
Increase from ₂ to high speed v ₁ . The second home position P ₁₀ serves as a reference position for reverse scanning movement in the reverse direction described later.

In this embodiment, the second home position P ₁₀
Performs detection of image edge 8a in the course of the inverted scanning movement in the opposite direction from, and the detection area is scanned at high speed v _3. This procedure is described in (7) to (8) below.

[0068] (7) with respect to the nominal theoretical position of the sheet edge 8a on the projection image, the actual position of the sheet edge which is expected to deviate by an error scanning position P ₁₃ ~ of (B) in FIG. 3 P
_If it is in the range of ₁₄ , the scanning movement speed changes to the low speed v ₄ in this range. The actual scanning movement speed decelerates from the position P ₁₂ which is in front of the fall distance required for deceleration from the high speed scanning movement speed v ₃ to the low speed image edge detection speed v ₄ .

(8) The operation sequence relating to the document edge determination and detection is the same as that shown in FIG.
The count number C _N of the scan motor drive synchronization signal when a is recognized is stored in the register X _a in the main body CPU 91. The contents of this register X _a is equivalent to a scanning position of the projected image edge 8a.

Next, the operation procedure in the pattern shown in FIG. 3C when the original direction switch 5 is ON, that is, when the longitudinal direction of the original film 1 is the X direction, is described in (9) below. ~ (12).

(9) The operation from the first home position P ₀ to the automatic focusing operation is the same as that described in the items (4) and (5) when the document switch 4 is ON.
Relative nominal theoretical position of the document edge 9b on the projection image, the actual location of the document edge that is expected to deviate by an error is to be in the range of scan position P ₁₆ to P _17, the scanning in the range The moving speed is changed to the low speed v ₂ . The actual scanning movement speed decelerates from the position P ₁₅ before the falling distance required for deceleration from the high speed scanning movement speed v ₁ to the low speed image edge detection speed v ₂ .

(10) The operation sequence relating to the document edge determination and detection is similar to the procedure shown in the flow chart of FIG. 4, and the count number C _N of the scanning motor drive synchronization signal when the document edge 9b is recognized. Is stored in the register X _b in the main body CPU 91. The content of this register _Xb corresponds to the scanning position of the projected image end 9b. After that, the scanning movement speed v ₂ is further reduced, and the scanning system is stopped at the scanning position P ₁₀ .

(11) The detection of the document edge 9a is performed in the process of reverse scanning movement from the second home position P _{10 in the} reverse direction, and the detection area is scanned at high speed v ₃ . Relative nominal theoretical position of the sheet edge 9a on the projection image, the actual location of the document edge that is expected to deviate by an error in the range of the scanning position P ₂₀ to P ₂₁ of FIG. 3 (C) Then, in this range, the scanning movement speed changes to the low speed v ₄ . The actual scanning movement speed decelerates from the position P ₁₉ which is in front of the falling distance required for deceleration from the high speed scanning movement speed v ₃ to the low speed image edge detection speed v ₄ .

(12) The operation sequence related to the document edge determination and detection is the same as that shown in FIG. 4 described above, and the count number C _N of the scanning motor drive synchronization signal when the document edge 9a is recognized is determined by the main body. stored in the register X _a in the CPU 91. The content of this register X _a corresponds to the scanning position of the projected image end 9 a.

According to the above operation procedure, the original end of the original film 1 can be detected, and the image data is output while referring to the contents of the registers _Xa and _Xb at the time of the normal image reading performed at the next scanning movement. By measuring the timing, it is possible to output the image data of the entire area from one end to the other end of the target image area without excess or deficiency.

As a result, the characteristic effects of this embodiment are as follows.

Since the control system of the apparatus recognizes the setting direction regarding the document length and width in advance of the document edge detection operation and limits the document edge detection area according to this recognition information, the detection operation time can be minimized. .

Since the automatic focusing operation is performed to maximize the optical resolution before the document edge detection is performed in the detection area, the image edge detection can be performed with high accuracy.

(Modification of the First Embodiment) The detection of the set direction in the vertical and horizontal directions of the original does not necessarily have to be performed by the switch as described above, and the original end detection area is reached as shown in FIG. It is also possible to detect the set direction by extracting the image data during the scanning movement until then and determining the detected light amount pattern of the image data in the Y direction.

FIG. 6 shows the directions of the projected images 8 and 9 to be read corresponding to the setting direction of the original film 1, and
The distribution pattern of the detected light amount of the line sensor 22 when receiving these projected images is shown. The end of each projected image corresponds to the opening end of the aperture of the slide mount 2 in which the original film 1 is filled. The image edges 8c and 9c indicate one image edge in the Y-axis direction, and the image edges 8d and 9d indicate the other image edge on the opposite side. When the longitudinal direction of the original film 1 is the Y-axis direction, as shown by the solid line waveform in FIG. 6, a pattern having a high detected light amount is obtained over the detection pixels S ₁ to S ₂ of the line sensor 22. When the longitudinal direction of the original film 1 is the X-axis direction, the detection pixels S ₃ to S of the line sensor 22 are detected as shown by the waveform of the one-dot chain line in FIG.
_A pattern with a high amount of detected light can be obtained over ₄ periods. Since S _{1 to} S ₂ has a wider pixel range than S _{3 to} S _4, it is possible to detect the set direction in the vertical and horizontal directions of the document by determining the distribution pattern of the detected light amount. As a result, the document edge detection operation area can be automatically switched.

The above-described method is not limited to the case of detecting the set direction of the document in the vertical and horizontal directions, but may be the document edge detection for the document of different sizes if the vertical and horizontal relationship ratio of the document to be used is clear. It can also be applied to. That is, by determining the image width in the Y direction, the position of the document edge in the X direction can be predicted, and the scanning area for detecting the document edge can be switched according to the document size by this prediction.

(Second Embodiment) In the first embodiment of the present invention described above, the speed of movement of the scanning system is changed in the detection area at the document edge, but the data sampling of the line sensor is performed in the same detection area. The object of the present invention can also be achieved by reducing the interval time. This can be realized by adding the function of changing the sampling interval of the sensor to the sensor driver 92 of FIG. 2 described in the first embodiment. In this case, it is not always necessary to change the moving speed of the scanning system in the document edge detection area. Hereinafter, this will be described as a second embodiment of the present invention.

In this embodiment, the function of changing the sampling interval of the sensor is added to the sensor driver 92 described in the first embodiment, and the illumination power supply 94 of FIG. The light quantity variable function of 19 is added, and the main body CPU 91 controls these functions. Other configurations are similar to those described with reference to FIGS. 1 and 2.

FIG. 7 shows the operation of this embodiment. FIG. 7A shows the direction of the projected image 8 to be read, and FIG. 7B shows the scanning position coordinates of the line sensor 22. The relationship with the scanning speed is shown. FIG. 7C shows the line sensor 2
2 shows the relationship between the scanning position coordinates and the sampling frequency of the line sensor 22, and FIG. 7D shows the relationship between the scanning position coordinates of the line sensor 22 and the light amount of the illumination lamp 19. The abscissa of (A) of FIG. 7 is (B), (C),
It is equivalent to the scanning position coordinates in (D). The timing chart of FIG. 8 shows changes in the line data sampling synchronization signal in the vicinity of the document edge detection area.

The line sensor 22 on the sensor support 21 shown in FIG. 1 _first moves from the first home position P ₀ to the projected image central position P ₃ at a high steady speed v ₁ , and temporarily moves to the central position P ₃ . Stop. Body CP at this position P ₃
U91 performs an autofocus operation. Next, the line sensor 22 moves toward the second home position P _{10 at} the high-speed steady speed v ₁ . Detection zone of the sheet edge 8b is between the first embodiment and the same coordinate position P ₆ to P _7, document edge remains speed of the v ₁ from the time when it reaches the coordinate position P ₆ in the middle movement of the The detection operation of 8b is performed, the second home position P ₁₀ is reached, and the operation is stopped.

The flowchart of FIG. 9 shows the operation sequence of the main body CPU 91 relating to the document edge detection in the second embodiment of the present invention.

At the stage immediately before the start of scanning movement of the sensor support 21, the line sensor 22 on the sensor support 21 is
Is in the first home position P ₀ . Here, in step 201, the initial value 0 is input to the count register in the main body CPU 91 which stores the pulse count number C _N of the scanning motor drive synchronization signal.

In step 202, the sampling data of the line sensor 22 is stored as an initial value in the address portion M ₁ in the RAM 98, and is secured as comparison data for later document edge detection.

In steps 203 and 204, the pulse is counted up each time the scanning motor drive synchronization signal is detected, and the count value C _N is stored in the count register.

In step 205, the line sensor 22
Whether or not the scanning position of has reached the point P ₆ is determined by the count number C _N of the scanning motor drive synchronization signal. That is, the count number C _N of the scan motor drive synchronization signal required for the scan position to reach the point P ₆ can be calculated in advance from the scan movement amount corresponding to one pulse of the scan motor drive synchronization signal, and this value is N _6. If the actual count number C _N does not reach this N ₆ , the process returns to step 203 to continue counting up the scan motor drive synchronization signal, and when the actual count number C _N reaches N ₆ , the process proceeds to the next step 206. .

In step 206, as shown in FIG. 7C, the sensor driver 92 increases the sampling frequency of the line sensor 22 from f ₀ to f _{1 according} to a command from the main body CPU 91. This makes it possible to finely detect the amount of movement of the scanning system per sampling interval,
It is possible to improve the resolution of the document edge detection. At this time,
As shown in FIG. 8, the sampling interval time becomes shorter, the accumulation time at the time of photoelectric conversion of the line sensor 22 decreases,
Since the amount of light for detecting the image edge becomes insufficient, the main body CPU 91 causes the illumination power source 9 to increase the amount of light of the lamp.
Control 4

At step 207, the sampling data of the line sensor 22 at this time is stored in the address portion M ₂ in the RAM 98.

In step 208, the contents of the address M ₂ which is the current sampling data are compared with the contents of the address M ₁ which is the data sampled one pulse before the scanning motor drive synchronizing signal with respect to the current scanning position. It is determined whether or not the document edge has been reached. This discriminating method can be realized in the same manner as the above-mentioned first embodiment. If it is not recognized as the document edge, the process proceeds to step 209, and if it is recognized as the document edge, the process proceeds to step 212.

In step 209, it is determined whether the scanning position is within the detection range of the document edge or has deviated from it by the pulse count number C _N of the motor drive synchronization signal.
That is, assuming that the count number of the scan motor drive synchronization signal required for the scan position to reach the point P ₇ is N ₇ , if the actual count pulse number C _N exceeds N ₇ , the document edge is recognized. Since it has reached the out-of-range of the scanning for detection without being able to do so, the routine proceeds to step 210, and processing such as an error display warning as an error operation is performed. If the actual count pulse number C _N has not reached N ₇ , it means that it is within the detection target range, so the routine proceeds to step 211, where the line sensor 22 of the line sensor 22 at this time is stored in the address portion M ₁ in the RAM 98. Address M ₂ which is sampling data
Is stored, the contents of address M ₁ are updated, and prepared as comparison data for the next document edge recognition. Then, the process returns to step 203. This operational loop is repeated until the document edge is recognized in step 208. When the document edge is recognized, the process proceeds to step 212.

In step 212, the count number C _N of the scanning motor drive synchronizing signal when the document edge is recognized is stored in the register X _b in the main body CPU 91. The contents of this register _Xb correspond to the scanning position of the projected image end 8b. Further, if the film original 1 to be used is of a standard specification and has good dimensional accuracy, a scanning motor corresponding to the scanning position from the position indicated by the register _Xb to the original end 8a based on the standard specification value. It is also possible to calculate the number of pulses of the drive synchronization signal. That is, from the document edge 8a to the document edge 8
If the number of pulses of the scanning motor drive synchronization signal corresponding to the distance on the standards to b and C _D, the number of pulses of the above and reducing the C _D from the value of the register X _b is obtained. Storing the difference value in register X _a.

In step 213, as shown in FIG. 7C, the sampling frequency of the line sensor 22 is set to f ₁
To normal f ₀ . At this time, the sampling interval time becomes longer as shown in FIG. 8, and at the same time, the lamp light quantity is returned to the original standard value as shown in FIG. 7D.

If the document edge is detected by the above operation procedure and the output timing of the image data is controlled by referring to the contents of the registers _Xa and _{Xb in} the next reading operation, the image data with high positional accuracy is output. can do.

As a result, the following points can be mentioned as characteristic effects of this embodiment.

Even in the image edge detection area, it is not necessary to reduce the moving speed of the scanning system, and the total processing time of the reading operation can be shortened.

In the image edge detection area, the accumulation time at the time of photoelectric conversion of the line sensor 22 is reduced. However, since the lamp light quantity is increased at this time, the desired detection ability can be maintained.

(Third Embodiment) A third embodiment of the present invention will be described with reference to FIG.

FIG. 10 shows an example in which the present invention is applied to an image reading apparatus in which the scanning means is an optical mirror system. In particular, this embodiment is suitable for a reflection original, and the sampling interval time is changed in the original edge detection area as in the second embodiment.

The sensor unit 50 is at a fixed position in the main body of the apparatus, and the line sensor 51 is mounted on it. The reflection original 52 is horizontally installed on the glass surface (not shown) of the original table above the apparatus of this embodiment.

The first mirror base 53 supports the first mirror 54 which is inclined by 45 ° with respect to the horizontal plane with the reflecting surface facing right.
It is supported by the scanning rail 59 so as to be movable in the X direction. The second mirror base 55 supports the second mirror 56 and the third mirror 57, and similarly to the first mirror base 53, is supported by the scanning rail 59 so as to be movable in the X direction. The second mirror 56 has a reflecting surface to the left and has a 4
The third mirror 57 is tilted by 5 °, and the reflecting surface of the third mirror 57 is set to the left, and the relative angle to the second mirror 57 is set to 90 °. The imaging lens 58 is arranged below each of the mirror bases, and as shown by arrows A ₁ , A ₂ , A ₃ , A ₄ , and A ₅ , the first mirror 54, the second mirror 56, and the third mirror 57. This is for forming an image of the reflected light of the original document 52 reflected and incident on the line sensor 51 of the sensor unit 50.

A drive gear 62 is fixed to the output shaft 61 of the stepping motor 60. The drive shaft 64 is rotatably supported with respect to the main body of the apparatus, and the driven gear 6 is provided at one end thereof.
3 is fixed, and the driven gear 63 meshes with the drive gear 62. The wire pulley 6 is attached to the other end of the drive shaft 64.
5 is fixed, and the wire 70 for moving the mirror system is wound around the wire pulley 65.

The wire 70 has a second pulley 6 rotatably supported by the second mirror base 55 from one end 70a thereof.
7 is wound around the wire pulley 65, wound around the wire pulley 65 several times, and then wound around a first pulley 66 rotatably supported on a pulley shaft 71 fixed to the apparatus body. , The other end 70b of the wire 70, after being wound around the second pulley 67 again, pulls the spring 6
It is supported by the apparatus main body via 8. First pulley 66
The wire 70 and the first mirror base 53 are joined by the joining member 69 on the way from the to the second pulley 67.

In the above structure, the stepping motor 6
When 0 rotates, the wire pulley 65 rotates via the drive gear 62 and the driven gear 63. Then, the first mirror base 53 moves as much as the wire pulley 65 winds the wire 70. As a result, the image of the original 52 is scanned. The second mirror base 55 is the first on the principle of a moving pulley.
The amount of movement is half that of the mirror base 53. Arrows A ₁ , A ₂ , A ₃ , A ₄ , A ₅ of the light flux path (optical path) from the original 52
1/2 Of, in the reciprocating path of the A _2, A ₄ of the amount of movement
Since the total optical path length remains unchanged regardless of the scanning position of the first mirror table 53, the image of the original 52 can always be projected onto the line sensor 51 of the sensor unit 50 and can be read. There is.

A linear encoder 82 is arranged on the left rear side of the first mirror base 53, and a pulse signal corresponding to the displacement of the displacement detection head 81 in the X direction is sent to the linear encoder 8.
It can be generated from 2. Since the displacement detection head 81 and the first mirror base 53 are connected by the connecting pin 80, the scanning position of the first mirror base 53 with respect to the original can be detected by counting the pulse signals from the linear encoder 82. . In a mirror scanning system in which the moving component has a large mass, even if the transmission system from the drive source to the mirror section has a difficulty in rigidity and the like, the position of the mirror base near the original scanning surface as in the present embodiment is set. By directly detecting and using this as the control information of the scanning position, the detection accuracy of the document edge can be improved as compared with the case where the position is controlled based on the drive synchronization signal of the drive source.

A series of scanning movement patterns at the time of original end detection scanning in this embodiment is basically the same as the drive mode shown in FIG. 7 of the second embodiment. However, the imaging lens 5
If the depth of field of 8 is deep, it is not necessary to perform the autofocus operation. Therefore, in this case, it is not necessary to stop the scanning system at the scanning position P ₃ for the automatic focusing operation, and it is possible to drive at a constant speed at the high speed v ₁ from the scanning positions P ₂ to P ₉ .

In the operation procedure shown in FIG. 9 of the second embodiment, the flow is advanced every time the drive synchronization signal of the scanning motor is counted up, and the end of the document is determined. The procedure for determining the document edge in the present embodiment is different in that the same operation procedure is performed depending on the pulse signal of the linear encoder 82. As described above, by applying the present invention, the document edge can be detected accurately and at high speed even for a reflective document.

As a result, the following points can be mentioned as the characteristic effects of this embodiment.

It can be applied to a reflection original by forming a mirror scanning system.

In the mirror scanning system in which the moving component has a large mass, even if the transmission system from the driving source to the mirror section has a difficulty in rigidity and the like, the position of the mirror base near the original scanning surface is detected, By using this detection information as control information of the scanning position, the accuracy of detecting the document edge can be further improved as compared with the case where the position is controlled based on the drive synchronization signal of the drive source.

(Others) In each of the above embodiments, when the scanning system is in the image edge detection area, either the scanning movement speed is changed or the line data sampling interval time is changed. However, if both functions are used together, that is, if the scanning movement speed is changed and the sampling interval time is changed at the same time, the resolution of the document edge detection is further improved without extending the total processing time of the reading operation. be able to.

[0115]

As described above, according to the present invention, it is possible to increase the detection accuracy of the document edge position and output image data with reference to this detection information. Therefore, according to the present invention, the data of the image area desired by the user can be output without excess or deficiency, the data output in which the necessary image area is lacking and the data output of the unnecessary area can be prevented, and the document edge can be prevented. Since the time lost due to the detection operation can be minimized, it is possible to obtain the effect that the processing time of the entire reading operation is hardly increased.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an internal structure of a first embodiment of the present invention in which the present invention is applied to an image reading apparatus for a film original having a structure in which a line sensor as a scanning system moves.

FIG. 2 is a block diagram showing a circuit configuration of a control system in the first embodiment of the present invention.

FIG. 3A is a plan view showing directions of projected images 8 and 9 corresponding to a setting direction of the original film 1 in the first embodiment of the present invention, and FIG. 3B is an original end with respect to the projected image 8. 9 is a graph showing the relationship between the scanning position coordinates of the line sensor 22 and the scanning speed during the detection operation, and (C) is the line sensor 2 during the document edge detection operation for the projected image 9.
It is a graph which shows the relationship between 2 scanning position coordinates and scanning speed.

FIG. 4 is a flowchart showing an operation procedure related to document edge determination and detection in the first embodiment of the present invention.

5A is a timing chart showing a relationship between a line data sampling synchronization signal and a scanning motor drive synchronization signal in a normal time, and FIG. 5B is a line data sampling synchronization signal in a document edge detection operation area; 7 is a timing chart showing a relationship with a scan motor drive synchronization signal.

FIG. 6 is a projected image 8 corresponding to the setting direction of the original film 1.
Line sensor 22 when receiving image light and direction 9 and
It is a conceptual diagram which shows the distribution pattern of the detected light amount of.

FIG. 7A is a diagram showing a direction of a projected image 8 in the second embodiment of the present invention, and FIG. 7B is a graph showing a relationship between scanning position coordinates of the line sensor 22 and speed. Yes, (C) is a graph showing the relationship between the scanning position coordinates of the line sensor 22 and the data sampling frequency of the line sensor, and (D) shows the relationship between the scanning position coordinates of the line sensor 22 and the light amount of the lamp. It is a graph.

FIG. 8 is a timing chart showing a change in sampling synchronization signal of line data in the vicinity of a document edge detection area in the second embodiment of the present invention.

FIG. 9 is a flowchart showing an operation procedure related to document edge determination and detection in the second embodiment of the present invention.

FIG. 10 is a perspective view showing an internal structure of a third embodiment of the present invention in which the present invention is applied to an image reading apparatus having an optical mirror system as a scanning unit.

[Explanation of symbols]

 1 Original Film 2 Slide Mount 4, 5 Original Direction Switch 10 Imaging Lens 14 Lens Driving Motor 22 Line Sensor 26 Scanning Motor 51 Line Sensor 53 First Mirror Stand 55 Second Mirror Stand 58 Imaging Lens 60 Scanning Motor 81 Detection Head 82 Linear encoder 88,97 ROM 89,98 RAM 90 Scan CPU 91 Main body CPU 92 Sensor driver 93 Lens drive motor driver 94 Lighting power supply 95 Scan motor driver 99 Image processing unit

Claims (6)

[Claims] 1. A photoelectric conversion means for reading an original image, in which light receiving elements are arranged linearly, and a scanning means for scanning the original image by relative movement of the photoelectric conversion means and the original image, While varying the ratio of the movement amount of the scanning unit to the output signal extraction interval time of the photoelectric conversion unit between the scanning region of the scanning unit and the other scanning region corresponding to the proximity of the end portion of the original image, And a control unit for recognizing a scanning position corresponding to an end portion of the document image by detecting a difference between output signals of the photoelectric conversion unit between the inner region side and the outer region side of the document image. Characteristic image reading device. 2. The control means makes variable the moving speed of the scanning means between the scanning area of the scanning means and the other scanning area corresponding to the vicinity of the end portion of the document image. The image reading device according to claim 1. 3. The control means makes the output signal extraction interval time of the photoelectric conversion means variable between the scanning area of the scanning means and the other scanning area corresponding to the vicinity of the edge of the original image. The image reading device according to claim 1 or 2, wherein 4. A detection means for detecting information about the vertical and horizontal directions of the original image or the size of the original image, the control means further comprising: an output signal of the photoelectric conversion means according to the detection information of the detection means. 4. The image reading apparatus according to claim 1, wherein the scanning movement region in which the ratio of the movement amount of the scanning unit to the extraction interval time changes is changed. 5. The automatic focusing means for automatically focusing and focusing the image light from the original image on the light receiving element of the photoelectric conversion means, and the control means is provided for the automatic focusing means. The image reading apparatus according to claim 1, wherein a scanning position corresponding to an end portion of the document image is recognized after the operation is performed. 6. The apparatus further comprises a document illuminating unit for varying an illumination light amount to the document, and the control unit synchronizes a change of an output signal extraction interval time of the photoelectric conversion unit with a change of the illumination light amount. The image reading device according to any one of claims 3 to 5, wherein: