JPS63145927A - Multiple signals processor - Google Patents

Abstract

PURPOSE:To accomplish an A/D converting operation for any kind of signal in a range close to the fullscale, by amplifying multiple kinds of analog signals varying in the range of change with different amplification factors to make the range of change thereof almost the same. CONSTITUTION:Output currents IX-IZ of light receiving elements 11-13 are converted into voltage signals with I/V conversion circuits 21-23. Here, when an I/V conversion resistance of the circuits 21-23 is represented by R1, output voltages thereof 21-23 are given by R1.IX, R1.IY and R1.IZ. These voltage signals are amplified with inversion amplification circuits 31-33 with amplification factors varying with signals and switched sequentially with a multiplexer 41 to be inputted into an A/D conversion circuit 42. The amplification factors of the circuits 31-33 are determined by an input resistance R2 and feedback resistances RX, RY and RZ respectively to obtain several voltage signals from the circuits 31-33 with the max. value thereof close to the max. convertible voltage Vmax of the circuit 42. This permits the performing of A/D conversion for any kind of signal with the circuit 42 in a range close to the fullscale.

Description

DETAILED DESCRIPTION OF THE INVENTION Summary of the Invention This is a device for converting a plurality of types of analog signals having different ranges of change into digital signals and capturing values with the ranges of change finally being made equal. A plurality of types of analog signals are amplified with different amplification factors to make the change range approximately the same, and then A/D conversion is performed. Fine corrections are made after A/D conversion.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for finally capturing a plurality of types of analog signals having different ranges of change in the form of digital signals.

BACKGROUND OF THE INVENTION A color identification device is one of devices that uses a plurality of types of analog signals having different ranges of change. The color sensor installed in the color identification device usually indicates R (red).

Three color signals of G (green) and B (blue) are output, and the ranges in which these color signals change are different. For example, when a certain color sensor is irradiated with 1000Lx light from light source A, the color signal current values for R, G, and B output from this color sensor are 150aA, 100nA, and 5, respectively.
It becomes 0 nA. Therefore, the current value of the color signal R changes in the range of about 0 to 150 nA depending on the color of the object to be colored, and the current values of the other color signals G and B change from 0 to 10 On, respectively.
It varies in the range of approximately A and 0 to 50 nA, respectively.

However, in one-color discrimination processing, R, G for white color
, B (which are approximately equal to the color signal values obtained when irradiating light from the light source A) are desired to be equal.

This is because white is considered to contain all color components equally. Therefore, it becomes necessary to adjust these color signals (full scale adjustment).

The easiest method to come up with is to make the amplification factors of the amplifier circuits that amplify each color signal different, and to make the change range of the signals output from the amplifier circuits the same. For this purpose, it is necessary to provide each amplifier circuit with a highly accurate variable resistor. However, variable resistors are expensive. There is a problem in that the resistance value fluctuates due to temperature changes, aging, vibrations, etc. Also, fine adjustment of the variable resistor is quite troublesome.

JP-A-60-54 as a method that does not use a variable resistor
There is one described in Japanese Patent No. 527. This realizes full scale adjustment using software.

A human analog signal is first converted into a digital signal by an A/D conversion circuit and then input to the CPU. The memory of the CPU stores coefficients for correcting digital quantities corresponding to the maximum and minimum values of each type of input signal to full-scale digital quantities. When a human input signal is A/D converted and captured, the value of the input signal under full scale is determined by correcting the digital quantity using this coefficient. However, with this method, when the variation range of the input analog signal is limited to a narrow range close to zero, the input signal always takes only a value close to zero, so it is not a standard for conversion in the A/D conversion circuit. The problem is that only a portion of the voltage is used and the accuracy of A/D conversion is always low. That is, a problem arises in that the accuracy of A/D conversion is different between a signal with a narrow range of change and a signal with a wide range of change.

Summary of the Invention Purpose of the Invention This invention eliminates the need to use a variable resistor as described in 1.1- above, and allows the A/D conversion range of the A/D conversion circuit to be expanded to almost full scale for all types of signals. The purpose is to provide a device that can be used.

Structure and Effect of the Invention The plurality of signal processing apparatuses according to the present invention amplify a plurality of types of analog signals having different change ranges with different amplification factors so that the change ranges after amplification are approximately the same. An amplifier circuit, an A/D conversion circuit that converts the outputs of multiple amplifier circuits into digital signals, and a digital system that is operated by one person using correction coefficients set for each signal in order to match the change range of multiple types of signals. The present invention is characterized by comprising means for correcting each of <a.

According to this invention, eleven or more types of analog signals are amplified by amplifier circuits each having a different amplification factor so that the change range after amplification is approximately the same. Therefore, A/D
What kind of conversion circuit! It is also possible to perform the A/D conversion operation on the jI signal in a range close to full scale.

Therefore, the A/D conversion accuracy is approximately the same for all types of signals. It is not necessary to strictly determine the amplification factor of the amplifier circuit. Therefore, the amplification factor of the amplifier circuit can be fixedly set using a fixed resistor that can obtain a value close to a desired amplification factor. Fixed resistors are inexpensive and are resistant to changes in temperature or aging.

Of course, it is also resistant to vibration. Since fine adjustment using a variable resistor is not required, complicated work can be omitted. Moreover, finally in software! Since the range of change of several types of signals is calibrated to be equal, and the maximum and minimum values of these signals match, it is suitable for various applications, such as ``double color discrimination processing''.

DESCRIPTION OF THE EMBODIMENTS In this embodiment, the present invention is applied to a color identification device.

FIG. 1 shows a schematic electrical configuration of a color identification device. The color sensor has three light receiving elements II.

12 and 13 are included. A filter is provided on the front surface of each of the light receiving elements 11-13 to pass light in a wavelength band representing a different specific color, and each of these light receiving elements tt-ta detects light of a different color, It outputs an output signal according to the intensity of the light. These output signals are, for example, R (red), G (green) and B (
represents each color component (blue). The light receiving elements 11 to 13 may be formed separately, or may be monolithically fabricated on one substrate together with a corresponding filter.

Output current 1, I of light receiving element 11.12.13.

V and 1 are converted into voltage signals corresponding to the I/V conversion circuits 21, 22, and 23 Teso(7) currents, respectively. If the current/voltage conversion resistance of these 1/V conversion circuits is R1,
The output voltage of the conversion circuit 21.22.23 is R1・1, R1
・I, R1・I are given by x
y z will be. These voltage signals are then amplified by inverting amplifier circuits 31, 32, 33 with different amplification factors for each signal, sequentially switched by a multiplexer 41, and inputted to an A/D conversion circuit 42. The amplification factors of the inverting amplifier circuits 31 to 33 are determined by the input resistor R2 and the feedback resistors R, R, and Rxyz, respectively, and are given by R/R2 and R/R2゜yR/R2, respectively. These amplification factors are such that the voltage signals after amplification have approximately the same value, and the A/
Maximum voltage V that can be A/D converted by the D conversion circuit 42
It is determined not to exceed aX. In other words, it is determined so that the 9th order equation holds true.

R1・I −R/R2t= v, axX
X R1-1-R/R2'-: V (1)yV
l1aXR1-1
-R/R2ζvIIlax zz As mentioned above, when the color sensor is irradiated with the A light source of 100OLIc, 1 -150nA, I
-100nA.

y Suppose that it becomes 1-50 nA. R1-IMΩ.

In R2-2, Ω, 'v -sv, sult, Rx
aX' (i7 is Ω, Rζ100 KΩ, Rζ200 KΩ y z.As the fixed resistors R, R, and R, it is best to choose metal film resistors that are less susceptible to temperature changes.There is a resistance of Rζ87 KΩ. If not, you can set a resistance of Ω to R8-B2, which is smaller than that.
, R-100 to Ω, R-200X
Y
It becomes ZKΩ.

For the sake of simplicity, the above example describes the case where the color sensor is irradiated with light from the A light source of 1000Lx, but in reality, the color sensor is irradiated with reflected light from a white object, and each light receiving element 11 at that time is .12.13 output current I,
Perform the above calculation with I and I as x y
z Yeah. When the color sensor is irradiated with reflected light from a white object, the output currents of the light receiving elements 11 to 13 become maximum.

In this way, a plurality of voltage a After being converted into a quantity, it is taken into the CPU 43. The digital signal taken into the CPU 43 is subjected to software processing, which will be described later.

The CPU 43 includes a RAM 44 for storing captured data and other data. ROM 45. Stores execution programs of the CPU 43 and other data. Also connected is a display device 46 that provides color identification results, instructions to the operator, and the like. A portion of the contents of the RAM 44 is shown in FIG. 2, and a portion of the contents of the ROM 45 is shown in FIG. 3.

The processing performed by the CPU 43 includes data setting processing for calibration and measurement processing for calibrating captured data into data that can be used for color identification. An example of these processes is the fourth
As shown in the figure.

As mentioned above, the output signal of the one-color sensor is transmitted through the amplifier circuits 31 to 31.
33 at different amplification factors, these output signals to the white plate have approximately the same value, which is close to the maximum value that can be A/D converted by the A/D conversion circuit 42. however.

-1- As mentioned above, it is necessary to calibrate the R, G, and B color sensor outputs for the white plate to be finally equal values. The setting process prepares the data necessary for this calibration.

Referring to FIG. 4, a setting mode is first set by operating switch input or the like (step 51).

Then, a dark level setting instruction is given to the second display device 46 (step 52), so the one-color sensor is covered with a lid or the like to prevent any light from entering from outside. It is preferable that the completion of this setting be inputted using a switch or the like (step 53). Then, the outputs of the A/D conversion circuit 42 that converted the color signals R, G, and B of the color sensor at this time into digital quantities are sequentially read and stored in the RAM 44 as the minimum values X, Y, and Zo (step 54). .55)
. These minimum values represent the offset of the amplifier circuit, and generally x, yo, and zo are different values. A/
The D conversion value may be read several times and the average value may be taken.

Next, an instruction to input the reflected light from the white plate to the two-color sensor is displayed on the display device 46 (step 56), so the operator can place the white plate in front of the color sensor or move the white plate on the conveyor. and enter a message to that effect (step 57).

Then, the A/D conversion values of the color signals R, G, and B output from the color sensor that detected the white board are read sequentially, and the maximum value
,Y.

Zl is stored in the RAM 44 (step 58,
59).

As shown in FIG. 3, the target maximum value A to be calibrated is stored in the ROM 45 in advance. This maximum value A will be set to a value equal to or close to the maximum voltage that can be A/D converted by the A/D conversion circuit 42. This maximum value A
is read from the ROM 45 and a correction coefficient is calculated using a quadratic equation (step 60).

G ■A/ (Xl-Xo) G -A/ (Y, -Yo') (2)G
-A/ (Z, -Zo) For example, A=sv, xo-yo-zo-to.

mV, Xl-4,7V, Yl-4,8V, Zl-4,4
If V, then G -5/4.8:=! 1.0
87. G-5/x
y4.7ζ 1.084. G
-5/4.4'! It becomes 1.136.

These correction coefficients G , G , G are RAM 44
When the x y z door is opened, the setting process ends (step 61).

Next, the measurement process will be explained. When the measurement mode is set, an instruction to set the sample is given on the display device 46 (step 71), so the operator places the sample to be measured in front of the color sensor or transports it on a conveyor, and then (Step 72). RAM
44 maximum value X1゜Y, Z and correction coefficient G
, G , G reads L l
x y z are output and stored in a predetermined work area (step 73). The A/D conversion values of the color signals R, G, and B of the color samples detected by the color sensor (these are
+Z) is read (step 74), and calibration is performed using a linear equation (step 75).

X = G (x −X o ) Y−G (Y−Yo) (3) Z−
G (z Z o ) The data x, y, z after this calibration are the measurement data, and R
Stored in AM.

Based on this measurement data, a discrimination standard for color identification is created, a single color identification process, etc. are performed.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of the electrical configuration of the color identification device, Fig. 2 shows part of the contents of RAM, Fig. 3 shows part of the contents of ROM, and Fig. 4 shows part of the contents of ROM. The figure is a flow chart showing an example of a processing procedure by the CPU. 31, 32.33...Amplification circuit. 42...A/D conversion circuit. 43...CPU0 or more''2

Claims (1)

[Claims] A plurality of amplification circuits that amplify a plurality of types of analog signals with different change ranges at different amplification factors so that the change ranges after amplification are approximately the same, and outputs of the plurality of amplification circuits. A/converts to digital signal
A processing device for a plurality of signals, comprising a D conversion circuit and means for correcting input digital signals, respectively, using correction coefficients set for each signal in order to match the change ranges of the plurality of types of signals.