JPS60212750A - Variable magnification system of picture processing - Google Patents

Abstract

PURPOSE:To reduce the capacity of a necessary memory, and also to obtain in a short time a control parameter required for a variable power operation by storing in advance only a parameter in several points of a basic variable power rate, and for instance, using a data on a straight line for connecting those points, as a control parameter in an optional magnification rate. CONSTITUTION:A basic magnification table, a basic magnification data address table, 10 kinds of basic magnification data tables and a use parameter table are placed on the memory of a digital controlling circuit DCU. In this regard, the basic variable power rate consists of 10 kinds of 50, 61, 71, 82, 86, 93, 100, 115, 122 and 141(%). For instance, in case a designated variable power rate M is 113%, a basic variable power rate MS selected as the nearest one to said rate attains to 115%. Therefore, a value in the designated variable power rate is obtained from a prescribed data and its inclination by referring to a data table of the variable power rate of 115%.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field The present invention relates to the setting of various control parameters in image processing having a variable magnification function, such as in a variable magnification copying machine.

■Prior Art Many of the latest copying machines are capable of multi-step or continuous magnification change. In addition, some lenses allow fine adjustment of the magnification ratio.

For example, when changing magnification in a copying machine, it is necessary to change various control parameters depending on each magnification. In other words, in a general copying machine, the rotational speed of the photoreceptor drum is kept constant, and the magnification of the imaging lens is adjusted according to the variable magnification.
By adjusting the IL, the scanning speed of the scanner, various timings of image reproduction, etc., the vertical and horizontal sizes of the original image and the vertical and horizontal sizes of the copied image are processed so that they have a predetermined proportional relationship. .

In this case, the magnification of the imaging lens, the scanning speed of the scanner,
Various control parameters such as image reproduction control system.

Generally, numerical values obtained by calculation and/or actual measurement are incorporated into the program of the control device, and are obtained by referring to them according to the variable magnification ratio. However, if the required magnification ratio is multistage or arbitrary as described above, the amount of control parameters required becomes enormous, and therefore a large capacity memory is required.

Therefore, a method has been proposed in which all control parameters are determined from the variable magnification factor by predetermined calculations. However, the most preferable relationship between the variable magnification and the corresponding control parameters changes along a special curve, for example as shown in Figure 1, so in order to perform this type of calculation, operations such as multiplication and division are required. This requires complex functional calculations that are performed many times. Therefore, the arithmetic processing program requires a large memory area. There are drawbacks such as the fact that it takes time to obtain predetermined parameters.

(2) Purpose It is an object of the present invention to reduce the required memory capacity and to obtain control parameters necessary for a variable magnification operation in a short time.

(2) In order to reduce the memory capacity for storing configuration control parameters, it is preferable to obtain the parameters by calculation. However, when complex calculations are performed, the above-mentioned disadvantages occur. However, in actual copying machines, A3. B4
．． A4. The frequency of use of the size ratio between specific sizes such as BS, that is, the basic magnification ratio, is overwhelmingly high.Therefore, even when performing stepless magnification, control parameters at several points of the basic magnification ratio are used. Memorize only the
For example, if data on a straight line connecting those points is used as a control parameter at an arbitrary magnification ratio, there will be some error since it is an approximate value at values other than the basic magnification ratio, but the required memory capacity will be reduced. It also makes calculations easier.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 2 shows a scanner driving device of a variable-reduction copying machine embodying the present invention. Referring to FIG. 2, a digital control circuit C
CU, clock pulse generator OSC;

Analog control circuit ACU, motor driver DRV.

It is equipped with a waveform shaping circuit STT, etc. The SVM is a DC servo motor that drives the scanner carriage.

A rotary encoder consisting of a rotating disk DK having a slit and a transmission type photosensor PH8 is coupled to the drive shaft of the motor SVM.

When the motor SVM rotates, a pulse signal (encoder pulse) with a period corresponding to the motor rotation speed is obtained at the output terminal of the photosensor PH8. Photo sensor P1 (2) is a sensor that detects the reference position II (home position) of the carriage.

When PH2 detects the home position, it outputs the signal SHP.
occurs. The Glock pulse generator O8C is a circuit that generates a pulse that serves as a phase reference in the phase comparison control mode, and the period of the pulse it outputs is set by the digital control circuit DCU.

The digital control circuit DCU is internally equipped with a microprocessor, a counter, etc. (not shown in the figure).

Further, the serial data transmission line of the digital control circuit DCU is connected to a serial transmission line TXD and a serial reception line RXD of a main control circuit (not shown) of the copying machine. Signals such as a scan start instruction, variable magnification, etc. are transmitted through these signal lines.

Description will be made with reference to FIG. 3, which shows a specific circuit configuration of the analog control circuit ACU shown in FIG. 2. This circuit includes a phase comparison circuit pcc, a digital/analog conversion unit DAtJ, a frequency/voltage conversion unit FVU,
Signal addition circuit V8asUM.

Friction compensation circuit 50. Amplifier AMP, current feedback circuit CFC
, a pulse width modulation circuit PWC, etc.

This circuit has SWI, SW2. SW3. SW4.
SW5. SW6. SW7. SW8. SW9 and 5WIO
are analog switches, and each signal line CS
W (see FIG. 2) by a digital control circuit DCU.

The phase comparator circuit FCC compares the phase of the reference signal applied from the clock pulse generator OSC to the reference phase signal input terminal +Raf or -Raf with the phase of the feedback pulse signal FBI obtained from the rotary encoder, and calculates the result. Output the corresponding level.

The digital/analog conversion unit DAU receives digital speed data DTV applied from the digital control circuit DCU.
The frequency/voltage conversion unit FVU outputs an analog signal level corresponding to the frequency of the feedback pulse output by the rotary encoder, that is, a voltage level corresponding to the motor speed.

The pulse width modulation circuit PWC generates a pulse signal Sd- whose pulse width is modulated according to the level of the signal (error signal) output by the amplifier AMP, and transmits the pulse signal Sd- to the motor driver DRV.
to be applied.

The motor drive operation of the analog control circuit ACU will be briefly explained. When starting the drive of the motor SVM, the mode is the speed comparison control mode. In this operation mode, the cycle of pulses output by the rotary encoder is controlled to match the target speed. When the motor SVM is stopped, the rotary encoder does not generate the pulse signal FB2.

Therefore, the output level (feedback voltage) of frequency/voltage conversion unit FVU is zero. When predetermined digital speed data DTV is applied to the digital/analog conversion unit DAU in this state, a corresponding analog level (target speed voltage) appears at the output terminal of this unit DAU, and if the feedback voltage is zero, The level corresponding to this target speed voltage is directly applied to the pulse width modulation circuit PWC, and the motor SvM is energized according to the level.

When the motor SvM is energized and starts rotating, the rotary encoder generates a pulse signal according to its rotation speed, which is applied to the frequency/voltage conversion unit FVU. A feedback voltage therefore appears at the output terminal of the unit FVU, which is dependent on the actual rotational speed of the motor. In this mode of operation.

Since a level corresponding to the difference between the target speed voltage and the feedback voltage appears at the output terminal of the amplifier AMP, an error signal level is generated so that the rotational speed of the motor SVM always matches the target speed, and the motor SVM changes accordingly. is energized.

However, in this speed comparison control mode, there is a delay in the response of the control system, and furthermore, as the motor speed approaches the target speed, the control amount becomes smaller, so when a disturbance or the like occurs, relatively small speed fluctuations occur. Therefore, when the motor speed becomes close to the target speed, the mode shifts to the phase comparison control mode.

In the phase comparison control (PLL) mode, the phase comparison circuit FCC detects and outputs the phase difference between the feedback pulse FBI obtained from the rotary encoder and the reference phase pulse output from the clock pulse generator O8C. The error signal level according to the phase difference is the amplifier AM.
P, which energizes the motor SVM. The pulse signal output by the clock pulse generator O8C is very stable, so if even the slightest disturbance is applied to the motor SVM and the speed attempts to fluctuate, a large error signal is immediately generated to restore it to its original state. Control.

The operation will now be described with reference to FIG. 4a, which schematically shows the operation of the digital control circuit DCU. When the power is turned on, first set each output port of the microcomputer to the initial level (
(non-energized level).

Clear the contents of memory and set initial values for each parameter. Also, keep the carriage in place! (a position slightly retreated from the home position).

Monitor the serial signal line TXD and wait until a scan start instruction is received from the main controller. When the start instruction is received, check the serial signal line TXD to find out how the current variable magnification is set. read from the main controller via. Using the magnification ratio read here, the magnification parameter set subroutine is executed. In this subroutine, data of various control parameters that change depending on the magnification ratio are set in a used parameter table (memory), as will be described later.

Of the data obtained in the usage parameter table, data 2 that is required by systems other than this scanner driving device, such as position data of the variable magnification lens, timing data for image reproduction control, etc., is transmitted to other controls via the serial signal line RXD. sent to the device.

When the external main controller notifies the completion of lens positioning via the serial signal line TXD,
Scanner position data, scanner speed data, scanner pulse cycle data, etc. are read by referring to the usage parameter table.

The analog control circuit ACU is set to the speed comparison control mode, and the scanner speed data DTV read from the table is applied to the digital/analog conversion unit DAU. Now, the analog control circuit ACU starts driving the motor SVM.

Wait until the photosensor PI42 detects the Baum position, and when the detection signal SHP appears, start counting the encoder pulses FB3. This counting of pulses is performed by a hardware counter, and thereafter the output of this counter, ie, the number of pulses, is monitored. When the number of pulses reaches a predetermined value (DP), the analog control circuit ACU is set to the phase comparison control mode. Here, scanner pulse period data CRf is applied to the clock pulse generator O8c.

When the number of pulses reaches the position data, motor SvMt
i-Decelerate and stop, immediately reverse the motor drive direction and return the carriage to the home position. When the Baum position is detected, the motor SvM is controlled to decelerate and stop, and the carriage is positioned by a predetermined value [C]. Furthermore, the analog control circuit ACU is set to a non-energized state and the next scan start instruction is awaited.

FIG. 4b shows the scaling parameter set subroutine of FIG. 4a, and FIG. 4c shows the arrangement of memory tables for storing references or results in this subroutine. Note that in the copying machine of this embodiment.

The basic magnification ratio is 50, 61.71, 82, 86°93.
There are 10 types: 100, 115, 122 and 141 (%).

Referring to FIG. 4c, a basic magnification table, a basic magnification data address table, 10 types of basic magnification data tables, and a usage parameter table are arranged on the memory of the digital control circuit DCU. The used parameter table is allocated to the address area of the read/write memory, and the other tables are allocated to the address area of the read-only memory in which data is stored in advance. Note that the symbol TBTA1. TBTA2 and AD RS n
(mouth=θ~9) are the basic magnification tables, respectively.

The basic magnification data address table and the 4C in the 0-order first table showing the start address of each basic magnification data table.
The specific contents of the basic magnification table (Table 1) and the basic magnification data address table (Table 2) shown in the figure are shown, and Table 2 shows the contents of the 100% basic magnification data table.

The processing of the scaling parameter set subroutine will be explained with reference to FIG. 4b of Table 1. First, the variable magnification M is loaded. The start address TBTA of the basic magnification table is set in pointer RA.
Set I and clear counter RB to 0. The data pointed to by pointer RA, that is, the data MS of the basic magnification table is loaded. If M>MS, the pointer RA and counter RB are incremented (+l) and the update of the data MS is repeated until this is not the case.

When MSMS, that is, the basic scaling factor MS closest to the designated scaling factor M, is found, the start address TBTA2 of the basic scaling factor data address table is set in the pointer RA, and the contents of the counter RB are added to RA. As a result, the value of the memory address in which the address of the head of the data table of the basic magnification ratio to be referenced is stored is entered into the pointer RA. Read address data ADR8n (n is one of O to 9) indicated by pointer RA and set this value to pointer RC. Read each data in the basic magnification data table as shown in Table 2.

For example, when reading scanner position data, ADR8
16 existing at address n+2 and ADR8 port +3
Read the bit position data (DATA) and the data of the slope (oELrA) at the magnification ratio (see FIG. 1) present in ADR3n+4.

Store the difference between the designated magnification ratio M and the specified basic magnification ratio MS in register ΔM, multiply 6M by the slope DELTA,
The result obtained by adding the position data DATA to the result is stored in the register DATAM. Now register DATAM
contains scanner position data corresponding to the specified magnification M.

For example, if the specified magnification change rate M is 113%, the basic magnification change rate MS selected as the closest one is 115%. So, referring to the data table of 115% variable magnification,
Therein, read predetermined data DATA and slope DELTA. Here, for example, DATA is 270 and slope DELTA is read.
If is 35, the value of DATAM will be:

DATAM-270+ (113-115)X35=2
00 In other words, the data obtained here is a value at the specified magnification that matches a function (broken line) obtained by connecting data at each basic magnification with a straight line.

The contents of register DATAM are stored at a predetermined position in the usage parameter table. A similar operation is performed for all parameters, and various parameters of the designated magnification ratio are stored in the used parameter table.

In the above embodiment, data was prepared only for commonly used basic magnification ratios, but if the error caused by the broken line approximation is large, data at predetermined magnification ratios between them can be added. The error can be made small enough for practical use.

(2) Effects As described above, according to the present invention, data of any magnification ratio can be obtained even though the amount of data prepared in advance is small, and the time required for processing is short because simple arithmetic processing is required.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the magnification ratio and the change in one control parameter. FIG. 2 is a block diagram illustrating one type of scanner driver embodying the invention. Figure 3 shows the analog control circuit ACU of the device shown in Figure 2.
FIG. 4a and 4b are flowcharts showing the general operation of the digital control circuit DCU shown in FIG. 2, and FIG. 4c is a memory map showing a part of the memory allocation of the DCU. SVM: DC servo motor DCU: Digital control circuit AC [J: Analog control circuit DK: Disk 1 zo 4 a

Claims (3)

[Claims] (1) In a scaling system for image processing that includes means for setting a scaling factor for image processing to three or more different predetermined scaling factors; a predetermined number of basic scaling factors smaller than the number of types of the predetermined scaling factors; A variable magnification method for single image processing, characterized in that control parameters for each are stored in advance, and the control parameters for an arbitrary magnification are determined by calculating the stored control parameters. (2) The variable magnification method for image processing according to claim (1), wherein the control parameters stored in advance include data on the slope of change at each predetermined magnification. (3) The control parameter at any magnification is determined by combining the pre-stored control parameter and its slope at the predetermined magnification closest to it, and the difference between those magnifications. A variable magnification method for image processing according to claim (2).