JPH0679151B2 - Image trimming method and apparatus - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for trimming a document image read by a scanner.

(Prior Art) In order to print with a color original image, it is necessary to create a plurality of, for example, three or four types of separated versions for each specific color of the original image. Conventionally, a so-called color separation scanner has been used in which the above is performed in the state of an electric signal. Further, in recent years, image editing work has been performed using a computer layout scanner system equipped with a large magnetic disk device.

(Problems to be Solved by the Invention) However, in the above layout system, the scanner captures an image in a wider range than the actual trimming range, displays the captured image on the display, and performs the trimming work. However, there is a problem that not only a large-capacity storage device is required, but also trimming work takes a long time and work efficiency is poor.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an image trimming method and apparatus that can obtain a decomposed image directly trimmed by a scanner.

(Means for Solving the Problem) In order to achieve this object, the present invention first performs pre-scanning with respect to a predetermined range of an original by the first image reading means, and then temporarily stores the read image signal in the image memory. , Display the image signal stored in this image memory on the monitor,
The trimming range is designated by the coordinate designating unit for the displayed image, the reading range of the second image reading unit is calculated based on the data from the coordinate designating unit, and the second range is calculated based on the calculation result. Image reading means scans the original to obtain a trimmed color separated image.

Next, the present invention relates to a first image reading means for reading a predetermined range of an original, an image memory for storing the image signal of the original read by the first scanning by the first image reading means, and the image memory. A monitor that reads out the stored image signal and displays the image, a coordinate value specifying unit that displays a trimming mark on the image displayed on the monitor and specifies the coordinate value of the trimming range of the image, and the coordinate value. Control means for calculating the range of the original read by the second image reading means based on the data from the designating means, and the trimmed image read by the second image reading means based on the data from the control means. Provided is an image trimming device including an image signal processing unit that performs color separation.

(Operation) In the present invention, the image signal read by the first image reading means in the pre-scan is temporarily stored in the image memory and then displayed on the monitor, and the trimming range is adjusted by the coordinate designating means with respect to the displayed image. Designate and calculate the reading range of the second image reading means based on the designated trimming range,
Based on the result of this calculation, the second image reading means can automatically trim the image and read the image to obtain a trimmed color separated image.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the apparatus of the present invention. In the figure, 1 is a reading scanning drum, 2 is an exposure scanning drum, 3 is a reading head, 4 is an exposure head, 5 is a controller, and 6 is a controller. Is a drum drive unit, 7 is an image signal processing unit, 8 is a film exposure unit, 9 is a one-dimensional image sensor, 10 is a lens,
11 is a stepping motor, 12 is a rotary ethane coder, 13 is a linear encoder, 14 is a preamplifier, 15 is a peak hold circuit, 16 is an A / D (analog / digital converter), 17 is a bidirectional bus driver, 18 is a buffer memory,
19 is an address counter, 20 is an address selector, 21 is a stepping motor driver, 22 and 23 are input / output controllers, 2
4 is an image memory, 25 is a monitor, 26 is a coordinate designation device, 2
7 is a gate. Note that F is an original image to be trimmed.

The reading / scanning drum 1 is intermittently driven by a stepping motor 11 in a predetermined cycle at the time of scanning before trimming, which will be described later.
During reading exposure (hereinafter referred to as main scanning), the drum driving unit 6 rotates together with the exposure scanning drum 2 at a constant synchronous speed.

The reading head 3 and the exposure head 4 are driven by a head driving mechanism (not shown), and are synchronized with the rotation of the scanning drums 1 and 2 during main scanning, intermittently at a predetermined cycle in a direction indicated by an arrow in FIG. To move continuously to scan the surface of the scanning drums 1 and 2. Then, at this time, the image signal S read from the original image F by the reading head 3 becomes an image signal S _S which has been subjected to a predetermined process by the image signal processing unit 7, and a predetermined portion is extracted by the gate 27 and the trimming image signal is obtained. After S _T , the image is supplied to the film exposure unit 8 and the image of the unexposed film (not shown) held on the scanning drum 2 is exposed by the exposure head 4, and the color-separated exposure for platemaking is performed. Get the film. Therefore, the operation during this main scan is
The operation of the scanner is the same with 27 open.

The one-dimensional image sensor (hereinafter, referred to as IS) 9 is composed of a CCD type one-dimensional solid-state image pickup device, etc. sequentially and a reading signal transfer unit by the clock C _K, and it serves to obtain an image signal S _P performs reading of line by line the image signals from the image projecting mirrored original F through the lens 10.

Here, the signal S _T is the scanning start signal of one line of IS9, signal E _N is also ended signal.

The stepping motor 11 receives I / O2 from the controller 5 during the pre-scan.
2 is driven and controlled via a driver 21 for each completed the reading of one line image signals S _P output by IS9, the scanning drum 1 by a predetermined rotation angle is rotated in the direction of the arrow, the original F by IS9 It works to read the image signal over the entire area.

In the above description, the one-line image reading scan by the IS9 is hereinafter referred to as line scanning, and the image signal reading scan by the rotation of the scanning drum 1 is hereinafter referred to as surface scanning.

The rotary encoder 12 detects the rotational angle position of the scanning drum 1 and supplies a position signal P _Y representing it to the control device 5.

The linear encoder 13 detects the position of the read head 3,
It serves to supply the control device 5 with a position signal P _X representing it.

Peak hold circuit 15 accepts the image signal S _P output from IS9 through the preamplifier 14, for reading IS9 clock C
The peak value of the image signal S _P is held in synchronization with _K , so that only the peak value of each pixel of the image signal S _P is A /
Operates as supplied to D16.

The bidirectional bus driver 17 is an A / D 16 which is a buffer memory for an image signal converted into, for example, 4-bit digital data.
When the image signals are read from the buffer memory 18, they are supplied to the control device 5, respectively.

Address counter 19 counts the clock C _K, serve to specify the address of one line of the image signal to be written to the buffer memory 18 by operating the address selector 20 by the count data. The address selector 20 uses the read address data R _E from the control device 5.
It also serves to read the image data for one line from the buffer memory 18.

The image memory 24 stores the image signal data read from the buffer memory 18, and stores the image signal data of the entire document F.

The monitor 25 functions to reproduce the image of the original image F by the image signal stored in the image memory 24.

The coordinate designation device 26 is provided with an input operation mechanism such as a keyboard switch and a joystick, and arbitrarily moves the position of a rectangular trimming mark of a preset size reproduced on the image display surface of the monitor 25 by the control device 5. To generate a position signal P _XY for

The gate 27 is an analog gate capable of gating the image signal S _S , and a gate signal G _T supplied from the controller 5
And operates to generate a trimming image signal S _T by extracting a part of the image signal S _{S at} a predetermined timing.

The control device 5 is operated by various programs incorporated as software or hardware, and has various data processing functions and control functions for other devices.

Next, the operation of the apparatus shown in FIG. 1 will be described.

The apparatus shown in FIG. 1 operates in the three modes of the pre-trimming scan, the subsequent trimming operation, and the main scan for exposing the trimmed image, which are already described.
First, the document F to be trimmed is set on the operation drum 1, and then scanning before trimming is started.

The image of the document F is formed on the photoelectric conversion portion of the IS9 by the lens 10. At this time, the photoelectric conversion elements arranged linearly in the IS9 are arranged so as to be parallel to the rotation axis of the scanning drum 1. Further, it is held at a position separated from the surface of the scanning drum 1 by a distance determined by the reading magnification of the document F and the focal length of the lens 10.

Therefore, the control device 5 supplies the start signal S _T and the end signal E _N to IS9 in synchronization with the clock C _K to perform line scanning, and controls in synchronization with the start signal S _T or the end signal E _N. A signal D _S is generated, the stepping motor 11 is driven via the I / D 22 and the driver 21, and the scanning drum 1 is rotated by a fixed angle to perform surface scanning. At this time,
The control signal 5 is a signal P _Y representing the rotational angle position of the scanning dot 1
Is taken in from the rotary encoder 12 and the rotational angle position of the scanning drum 1 is controlled in accordance with a preset document enlargement ratio so that the surface scanning is performed line by line by the correct scanning line.

As a result, from IS9, clock C for each pixel of document F
_The image signals S _P read in synchronization with _K are sequentially taken out line by line, and the signals S _P are supplied to the preamplifier 14
After being peak-held for each pixel by the peak hold circuit 15 via A, and digitized by the A / D 16, it is supplied from the bidirectional bus driver 17 to the buffer memory 18. At this time, since the write address of the buffer memory 18 is controlled via the address selector 20 by the data of the address counter 19 that receives the clock C _K,
Image signals S _P output from IS9 would be incorporated into one line at a time buffer memory 18 at the address different for each pixel.

Therefore, the means device 5 supplies the read address data R _E to the address selector 20 every time when the image signal for one line is taken into the buffer memory 18, and the buffer memory 18 outputs 1 to 1.
An image signal for a line is read out, processed as a set of appropriate pixel data according to a preset document size and exposure magnification, and transferred to the image memory 24 via the I / O 23.

Therefore, when the above pre-trimming scanning is completed for the entire document F, the image information of the document F is stored in the image memory 24 as a predetermined number (M × N) of pixel data, as shown in FIG. Will be. In FIG. 2, if P ₀ is the scanning start point before trimming on the surface of the scanning drum 1, this P ₀ is the origin, the line scanning direction by IS9 is also x, and the surface scanning direction by the rotation of the scanning drum 1 A coordinate system can be defined as y. If the number of photoelectric conversion elements of IS9 is N, the number of pixels per line is N, and if there are M scanning lines, the total number of pixels is as described above. M × N
It becomes an individual. Therefore, the position of arbitrary pixel data on the image plane read by the pre-trimming scan is the second
As shown in the figure, it can be represented by a scan line number I and a pixel number J in each scan line, of which the number I is the signal P _Y obtained from the rotary encoder 12,
The number J corresponds to any position of the IS9 photoelectric conversion element.

Now, when the pre-trimming scanning is completed in this way, the process proceeds to the trimming operation, and the control device 5 displays the image of the document F and the trimming mark of the preset size on the monitor 25 based on the data read from the image memory 24. Make it appear.

Then, the operator operates the coordinate designation device 26,
A document F obtained by pre-scanning by moving the trimming mark on the image projection surface of the monitor 25 by the position signal P _XY
Trimming is performed on the image surface of, and an appropriate trimming range is designated. This designation is input to the control operation 5 by a designation completion operation by the operator, for example.

Therefore, the control device 5 knows the line number I _m and the pixel number J _n of the reference point P _T of the trimming range from the position signal P _XY input at that time, and then the coordinate value in the coordinate system shown in FIG. Calculate and store X _T , Y _T.

When the calculation of the reference point P _T (X _T , Y _T ) is completed, the control device 5 switches to the main scanning, and after the unexposed film (not shown) is attached to the scanning drum 2, the drum driving unit 6 The scanning drums 1 and 2 are driven to rotate at a constant speed, and the image signal S from the reading head 3 is supplied to the film exposure unit 8 through the gate 27 from the image signal processing circuit 7, and the exposure head 4 trims an image. The exposure at this time is started, and the operation at this time will be described below.

First, for the sake of explanation, as shown in FIG. 3, an appropriate origin D ₀ is set on the surface of the scanning drum 1, the feeding direction of the reading head 3 is X, the direction opposite to the rotating direction of the scanning drum 1, that is, the surface scanning. A coordinate system whose direction is Y is defined so that the position of the scanning point on the surface of the scanning drum 1 can be displayed in XY coordinates.

Then, the X and Y coordinates of this scanning point can be immediately detected by the position signal P _X obtained by the linear encoder 13 and the position signal P _Y from the rotary encoder 12, and the trimming scanning reference point P _T is calculated. can do.

However, since IS9 is often used in a fixed state, the origin D ₀ of the scanning drum 1 and the origin of the previous scanning machine are
P ₀ and not Do match Therefore, the origin P ₀ as shown in FIG. 3
Has an offset (X ₀ , Y ₀ ) with respect to the origin D ₀ .
Therefore, the coordinates (X _T , Y _T ) of the trimming reference point P _{T in} the XY coordinate system Will be represented by Therefore, the position coordinates (X ₀ , Y ₀ ) of the origin P _{0 in} the XY coordinate system are obtained from the position signals P _X and P _Y in advance during the pre-trimming scan, and this can be stored in the control device 5 according to the equation. The reference point P _T can be easily calculated.

Therefore, when the control device 5 starts the main scanning, the gate signal G _T is generated by the detection of the reference point P _T , the gate 27 is operated at a predetermined timing, and a part of the image signal S _S is extracted and trimmed. The image signal S _T is extracted, and the unexposed film is exposed by the exposure head 4 so that the trimming separation plate is immediately exposed. The operation at this time is shown in the timing charts of FIGS. 3 and 4. A chart will be used for explanation.

In FIG. 3, the scan portion of the document F before trimming is F ₀ ,
The range designated by the trimming mark, that is, the trimming portion is F _T , and the trimming size is dx, dy.
Then, the original F has no pattern except for the range of the pre-trimming scanning portion F ₀ .

Then, the image signal S _S obtained by performing main scanning on this has a waveform as shown in FIG. 4, for example. In addition, in FIG.
L is the period required for the scanning drum 1 to make one rotation, that is, 1
This is a scanning line period.

In this state, when the control device 5 detects the reference point P _T as described above, it outputs a pulse having a width equal to the time Tdy required for the scanning point to move the distance dy from the time t ₀ for one scanning line period. It is generated for each L to be a gate signal G _T, and the generation of this pulse is such that the scanning point is a distance dx from the reference point P _{T in the} X direction.
Repeat for a time equal to the time Tdx.

As a result, the gate 27 is turned on each time a pulse of the gate signal G _T appears to allow the image signal S _S to pass therethrough, and a part thereof outputs the trimming image signal S _T extracted at a predetermined timing, The trimmed image is directly exposed on the unexposed film of the scanning drum 2.

It should be noted that how the exposure state of the unexposed film of the scanning drum 2 when the gate 27 is turned off is
It may be set arbitrarily according to the trimming plate making conditions, and may be left unexposed or may be completely exposed.

Therefore, according to the above-described embodiment, it is possible to perform arbitrary trimming in the color separation operation by the scanner and immediately expose only the trimmed portion, and the reading operation of the image signal by the pre-trimming scanning is very fast due to IS9. Only one within line scanning and rotation of scanning drum 1
Since it is completed by the surface scanning by the turning, it is possible to sufficiently shorten the time required for the pre-scanning.

By the way, in this embodiment, if the image signal obtained by the pre-trimming scan is reproduced on the monitor 25 and the pixel density of the reproduced image is low, the trimming accuracy also deteriorates.

However, for example, when using IS9 with 512 photoelectric conversion elements, which has a relatively small number of photoelectric conversion elements, and scanning a 10 cm x 8 cm original with this, the exposure magnification is 100%.
The error in the trimming range that is allowed at is within ± 0.1 mm because the resolution pitch of IS9 is about 0.2 mm, and it is possible to maintain sufficient accuracy for practical use.

Moreover, when the same IS9 is used and the short side of the A4 size (210 × 297) is scanned in parallel with the rotation axis of the scanning drum 1, IS9
The resolution pitch of is about 0.41mm, so the error in the trimming range is within ± 0.205mm, and sufficient accuracy can be obtained even in this case.

On the other hand, since a monochrome monitor is sufficient for the monitor 25, the storage capacity required for the image memory 24 is one pixel for a pattern when the total number of pixels of the image to be reproduced on the monitor 25 is set to 512 × 512. It is enough to use 8 gradations 3 bits and 1 bit for trimming marks, so 128KBy as a whole
There is enough te, and you don't have to use a large storage capacity.

In the apparatus shown in FIG. 1, the scanning drums 1, 2
It is configured to perform trimming with a normal plate-making scanner equipped with the. Therefore, the operations from pre-trimming scanning to main scanning can be performed with the scanning drum 1 set in the main body, and trimming is performed. However, the present invention may be configured so that only the pre-trimming scanning mechanism is used as a dedicated device.

However, in the embodiment in which the dedicated device is used as described above, the pre-trimming scanning and the main scanning are performed by different devices, so that the rotary encoder for detecting an arbitrary point on the scanning drum is used. A linear encoder, a linear encoder, etc. are also required for each device, and further data regarding the correspondence between the scanning positions between the two devices is stored in the control device of the device that performs main scanning. Although necessary, the pre-trimming scan and the main scan can be performed independently, which allows flexibility in the plate making work.

(Effects of the Invention) As described above, in the present invention, the image signal read by the first image reading means in the pre-scan is temporarily stored in the image memory and then displayed on the monitor, and the coordinates are designated for the displayed image. The trimming range is designated by the means, the reading range of the second image reading means is calculated based on the designated trimming range, and the second image reading means automatically trims based on the calculation result. Since an image can be read and a color-separated image that has been trimmed can be obtained, in a computer layout scanner system equipped with a large magnetic disk device, it is sufficient to retain only the data of the trimmed image as the input image. Since the amount is reduced, the magnetic disk pack can be effectively used, and the layout scanner system is used for trimming processing. Compared with the case, the present invention has an excellent effect that the trimming can be performed more easily and easily, and the system configuration does not require a large scale, so that the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the apparatus of the present invention, FIG. 2 is a schematic diagram showing sampling points of a prescan portion of a document, and FIG. 3 is a prescan portion and trimming of a document on a scanning drum. FIG. 4 is a schematic diagram showing a portion, and FIG. 4 is a timing chart showing the relationship among the image signal, the trimming image signal, and the gate signal. 1, 2 ... Scanning drum, 3 ... Read head, 4 ... Exposure head, 5 ... Control device, 6 ... Drum drive section, 7 ... Image signal processing section, 8 ... Film exposure section, 9 ... One-dimensional image Memory (IS) 10 …… Lens, 11 …… Stepping motor 12 …… Rotary encoder 13 …… Linear encoder 14 …… Preamplifier 15 …… Peak hold circuit 16 …… A / D (analog / digital converter) 17 …… Bidirectional bus driver 18 …… Buffer memory 19 …… Address counter 20 …… Address selector 21 …… Stepping motor driver 22, 23 …… I / O (input / output controller) 24 …… Image memory, 25 …… Monitor 26 …… Coordinate designation device, 27 …… Gate

Claims (2)

[Claims] 1. A predetermined range of an original is prescanned by a first image reading means, the read image signal is temporarily stored in an image memory, and then the image signal stored in the image memory is displayed on a monitor. The trimming range is designated by the coordinate designating unit for the displayed image, the reading range of the second image reading unit is calculated based on the data from the coordinate designating unit, and the first range is calculated based on the calculation result. An image trimming method, wherein the second image reading means scans the original document to obtain a color-separated image that has been trimmed. 2. A first image reading means for reading a predetermined range of an original, an image memory for storing an image signal of the original read by the first image reading means in a prescan, and an image memory stored in the image memory. A monitor that reads out the image signal and displays the image, a coordinate value specifying unit that displays the trimming mark on the image displayed on the monitor and specifies the coordinate value of the trimming range of the image, and the coordinate value specifying unit. Control means for calculating the range of the original read by the second image reading means based on data from the second image reading means, and color separation of the trimmed image read by the second image reading means based on the data from the control means. An image trimming device comprising: an image signal processing means for performing the following.