JP3199558B2 - Apparatus and method for averaging input signal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an input signal averaging device and an averaging method for averaging input signals which are sequentially read, and more particularly to a circuit for reading a signal containing various distortions. This is suitable for a distortion data averaging process for removing a noise component (a temporally varying component in the distortion component) at the time of detection of.

[0002]

2. Description of the Related Art In a reading circuit of various solid-state imaging sensors such as a CCD (Charge Coupled Device), a distortion component of a sensor read signal is detected, and the detected distortion component is used to remove the distortion component from the sensor read signal. In order to perform accurate correction by performing the above, only the steady distortion component after removing the temporal fluctuation component (noise component) from the detected distortion components is extracted, and this is used as the distortion for correction. It is necessary to use detection data. For this reason, strain data has conventionally been averaged to remove temporal fluctuations from the detected strain data, and it has been required to efficiently perform this strain data averaging process.

FIG. 8 shows a conventional typical configuration example of a distortion data averaging circuit constituting a CCD reading circuit. In FIG. 8, signal A is detected distortion data (including a steady component and a fluctuation component), signal B is data obtained by reading data A stored in a line memory, and signal C is added after one line is detected. The result of the averaging operation for performing the multiplication, the data during the operation, and the signal D are data obtained by reading the data C stored in the line memory. Reference numeral 31 denotes a first line memory for storing detected distortion data A, and reference numeral 33 denotes an average number of times of addition of the detected distortion data B read from the line memory 31 for each pixel, and divides the sum by the average number. An averaging operation circuit 32 for performing operations such as the above, and a second line memory 32 for storing data C. The averaging operation circuit 33 includes an adder 34 that adds the output data B of the first line memory 31 and the output data D of the second line memory 32, and an average number (average number) of the output data D of the second line memory 32. Reciprocal 1 / n of the number of processings) n (=
G), a multiplier 35 that multiplies the data G by 1 / n
(Read only memory) for supplying the multiplier to the multiplier 35
36, and a selector 37 for selectively outputting one of the output data E of the adder 34 and the output data H of the multiplier 35 to the second line memory 32 as data C.

In the case of the conventional circuit configuration shown in FIG.
A cycle of detecting the distortion of one line of the sensor output and storing the detected distortion data A in the first line memory 31 (a detection cycle of one line);
The adder 34 performs addition of the read data B of the first line memory 31 and the read data D of the second line memory 32 which stores the added data up to that point. As shown in FIG. 9, the cycle of performing the operation of storing data in the memory 32 (averaging operation cycle) is performed in series. These two cycles are repeated, and when the sum of the average number is obtained, the sum is divided by the average number n by the multiplier 35, whereby the average value of the detected distortion data is obtained for each pixel. Strain data from which components have been removed can be obtained. FIG. 10 shows the details of this sequence.

The timing chart of the conventional example shown in FIG. 10 is a series of time series (1), (2), and (3) which are temporally continuous, but are separately illustrated for the sake of space. FIG. 10A shows a first cycle in which the detection data A is written to the first line memory 31. In FIG. 10B, the adder 34 adds the data of the same address in the first line memory 31 and the data of the same address in the second line memory 32, and adds the addition result E via the selector 37 to the second line memory 32. This is the second cycle of writing to the. The operations of the first and second cycles are repeated from the first line to the (n-1) th line (see FIG. 9). (3) in FIG. 10 is a third cycle in which the data D in the second line memory 32 is multiplied by 1 / n, and the multiplication result is written in the second line memory 32. As described above, the n-th line is also multiplied by 1 / n.

[0006]

However, in the above-mentioned prior art, since the first and second cycles are not performed in parallel, the averaged distortion data is divided by the last division. It has the disadvantage that it takes a long time to get it. Further, there is a problem that a total of two sets of line memories are required, that is, a first line memory 31 for storing detection data and a second line memory 32 for storing calculation results.

Further, since it is necessary to store the additional data for the average number of times of the detected distortion data in the second line memory 32, the number of bits is smaller than that of the first line memory 31 for storing the detected distortion data. There is a problem that many things are required.

The present invention has been made in view of the above-mentioned points of the prior art, and an object of the present invention is to provide a method for removing a temporal variation component (noise component) from detected distortion data. To provide an input signal averaging apparatus and an averaging method capable of performing data averaging processing in parallel with the distortion data detection and performing the processing with a small circuit size. It is in.

[0009]

In order to achieve the above object, an input signal averaging device according to the present invention is a device for averaging sequentially read input signals, and selectively outputs an input signal and a stored value. Input selection means, multiplication means for multiplying an output value of the input selection means by a weighting factor, addition means for adding the output value of the multiplication means, and storage means for storing the output value of the addition means The input selection means alternately selects an input signal and a storage value of the storage means at a fixed period and outputs the selected signal to the multiplication means.When the input signal is selected, the multiplication means outputs the output value of the input selection means. Weighting factor 1 / n
(N is the number of times the input signal has been read at that time), and when a stored value is selected, the output value of the input selection means is multiplied by (n-1) / n as a weighting factor, and the addition is performed. Output means, and the addition means adds the pair of output values of the multiplication means and outputs the result to the storage means.

Preferably, in one aspect of the present invention, the adding means comprises a register for adding a pair of outputs serially output from the multiplying means and an adder. can do.

Preferably, in another aspect of the present invention, the storage means is a line memory, and the input signal selectively output from the input selection means and the storage value are line data. can do.

Preferably, in another aspect of the present invention, the storage means is a register, and the input signal and the storage value selected and output from the input selection means are each one-point data. It can be.

Preferably, in another aspect of the present invention, the weighting factors 1 / n, (n−n) are set according to a count value n of the number of times the input signal is read by the input selection means.
1) The multiplying means has weighting coefficient generating means for generating / n alternately, and further, the input selecting means, the multiplying means, and the adding means until the value of n reaches a predetermined averaging count m. And control means for causing each processing of the storage means to be repeatedly performed to average the input signal.

[0014] In another aspect of the present invention, preferably, the input signal is a signal from a line scanner.

[0015] In another aspect of the present invention, preferably, the input signal is a distortion signal.

According to still another preferred embodiment of the present invention, the averaging device for an input signal includes a circuit for reading a signal containing various distortions. And a distortion data averaging process for removing a noise component.

Further, the averaging method of the input signal according to the present invention comprises:
In a method of averaging input signals sequentially read,
Alternately selecting and outputting an input signal of a predetermined bit length and a storage value of the storage means in a fixed cycle, and, when the input signal is selected, 1 /
n (n is the number of readings of the input signal at that time) and outputs the result. When the stored value is selected, the stored value is multiplied by (n-1) / n as a weighting factor and output. Adding a value multiplied by the weighting factor 1 / n and a value multiplied by the weighting factor (n-1) / n; and storing the result of the addition as the storage value in the storage unit. And storing each of said steps as n
Is repeated until the value reaches a predetermined number m.

[0018] Preferably, the method of the present invention is characterized in that the input signal and the stored value are handled in line data or one point data unit.

[0019]

According to the present invention, an input signal and a stored value are alternately selected and input, and the input signal is multiplied by 1 / n (n is the number of readings of the input signal at that time) as a weighting factor. Since the process of multiplying the stored value by (n-1) / n as a weighting factor and adding the result of the multiplication and using the result as the stored value is repeated until n reaches a predetermined number m, the memory capacity is reduced and the memory capacity is reduced appropriately. Averaged data such as average distortion data can be obtained in parallel with the detection of distortion data on a circuit scale without wasting operation time.

[0020]

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

(Basic Configuration) FIG. 1 shows a basic configuration of the present invention of an averaging device for averaging an input signal containing various distortions. The input selection means 1 alternately selects an input signal (for example, detected distortion data) A and a storage value (average distortion data up to the previous time) M of the storage means 4 at a fixed period, and outputs the selected signal to the multiplication means 2.
When the input signal A is selected, the multiplying means 2 adds a first weighting factor 1 / n for averaging to the output value of the input selecting means 1.
(Where n is the number of readings of the input signal at that time), and when the stored value M is selected, the output value of the input selecting means 1 is added to the second weighting coefficient (n-1) for averaging. ) / N
And outputs the result to the adding means 3. The adding means 3 adds the weighted input signal and the weighted storage value (that is, the average distortion data up to the previous time) to obtain the average distortion data L.
Get. The storage means 4 holds the average distortion data at each read count, which is the output value L of the addition means 3, supplies the average distortion data M up to the previous time to the input selection means 1 at the next averaging operation, and The average strain data after the conversion is retained.

As the input signal A, a video signal from a line scanner (not shown) or another distortion signal is usually applied. Number of readings n of input signal A and stored value B
Is a line data or a single point data. When averaging processing is performed on line data, a line memory is used as the storage unit 4. When averaging processing is performed on one point of data, a register is used as the storage unit 4. The multiplication means 2 can be composed of a multiplier and a weight coefficient generation means. Further, the adding means 3 can be constituted by an adder and a register.

As can be seen from FIG. 1, the detected distortion data A and
The operation of adding the average data M stored in the storage means 4 up to the previous time with weighting according to the average number n (the number of readings) at that time is repeated by the average number of times. Here, the value of A _n ... n-th averaging Operation A, M _n ... n-th averaging operation when the values of M, L _n ... n-th averaging operation when the values of L, a, Assuming that n = 1, 2, 3,..., m (m is the number of times of averaging), the above averaging operation is represented by the following equation.

In the first average (the first data is kept as it is), A ₁ × 1 + M ₁ × 0 = A ₁ = L ₁ → M _{2 In the} second average,

[0025]

(Equation 1)

In the n-th average,

[0027]

(Equation 2)

The final result after averaging m times is

[0029]

(Equation 3)

## EQU1 ## In this way, if the above calculation operation is repeated m times, the number of times the user actually wants to perform averaging, L _m is obtained as the average distortion data.

Using such a basic structure, for example, C
If a distortion data averaging circuit such as a CD reading circuit is configured, the averaging operation can be performed in parallel with the distortion detection operation only by having a line memory for one line as the storage unit 4, for example. Therefore, it is possible to reduce the circuit scale (that is, it is sufficient to have only one set of line memories) and obtain average data immediately after distortion detection. Further, in the case of this configuration, an averaging circuit that satisfies the conditions of the average number of times and the average accuracy can be configured only by adjusting the input signal (detection distortion data) A and the number of bits of the storage unit 4.

For example, in an application in which the average number of times is small and the average accuracy is not so required (for example, when the noise component is equal to the number LSB of the detected distortion data), the number of bits of the detected distortion data and the number of bits of the storage means 4 are reduced. Even at the same level, a practically acceptable result can be obtained.

As described above, according to the present invention, the circuit scale,
It is possible to efficiently detect only the steady component of the strain data with respect to the operation time. That is, when obtaining distortion data for distortion correction of a CCD reading circuit or the like, the operation of weighting the detected distortion data and the average distortion data up to that time and adding them to obtain the average distortion data is performed in parallel with the distortion detection. Therefore, the time required to obtain the distortion data from which the fluctuation component has been removed can be shortened, and the circuit scale can be reduced.

(First Embodiment) Next, a first embodiment of the present invention will be described with reference to FIGS. This embodiment is an example in which a line memory is used as the storage unit 4.

FIG. 2 shows a circuit configuration of the first embodiment of the present invention. In FIG. 2, reference numeral 11 denotes a selector corresponding to the input selecting means 1 shown in FIG. Are alternately selected, and the multiplier 12
Output to

A signal B input to the multiplier 12 is a selection output of A or M, and a signal F is a selection output of C or D selectively supplied through the selector 13 in synchronization with the selection of A and B. is there. C is the first weighting factor 1 / n (n is the average number of times at that time), and D is the second weighting factor (n-1) / n
And these coefficients are R according to the read address E.
Read from OM14. The address E represents the average number n at that time, and is the count output value of the counter 15. A magnitude comparator (comparator) calculates the average number n at that point indicated by E and the final number m to be averaged indicated by G.
16 and H, which is the magnitude comparison result of n and m, is n> m
Indicates that the control circuit (controller) 17
Resets the counter 15. I is a reset signal to the counter 15 and a count clock. The control circuit 17 outputs a reset signal N to the register 19 and a select timing signal to the selectors 11 and 13 in addition to the signal I. The components 13 to 17 such as the selector and the ROM constitute a weighting coefficient generating means, and further constitute the multiplying means 2 of FIG.

The output J of the multiplier 12, that is, A × C (=
The calculation results of A × 1 / n) or M × D (= M × (n−1) / n) are sequentially supplied to the adder 18. Here, as the operation clock of the averaging circuit, a clock of several times the data rate (usually about 8 or 16 times)
Use In order to calculate the average result [(A × C) + (M × D)], first, the register 19 at the subsequent stage of the adder 18 is used.
Is reset by the reset signal N, and after the reset is released, the value of K at this time is (M ×
D) is held in the register 19, and the data obtained by adding the data L (= M × D) held in the register 19 and the output J (= A × C) of the multiplier 12 at the next clock [(A × C) + (M ×
D)] is held in the register 19. At this time, the output L of the register 19 is L = (A × C) + (M × D).

When the operation of storing the value of L in the line memory 20 for one line is performed, one line of average data at that time is obtained. When the calculation for one line is completed, the counter 15 is incremented by one. The adder 18 and the register 19 correspond to the adder 3 of FIG.
And the line memory 20 corresponds to the storage unit 4 in FIG.

When the above operation is repeated for the number of lines to be finally averaged m times, the output H of the magnitude comparator 16 acts on the control circuit 17 to reset the counter 15 and terminate this operation. At this point, the final average data for one line is stored in the line memory 20. The average data can be output and displayed on an output means such as a display or a printer via the interface circuit 22. Further, the average data can be used as distortion data for distortion correction.

FIG. 3 is a timing chart showing the contents of each signal of the circuit of the embodiment shown in FIG. 2. FIG. 4 is a conceptual diagram showing a state in which detection and averaging operation for one line are simultaneously executed in the circuit of FIG. Is shown in

FIG. 5 schematically shows the correspondence between the output of a line scanner (not shown) and the data stored in the line memory 20.

(1) The line scanner reads pixels in one line one by one, and reads the read data for each pixel in A / D.
After that, the digital data is input to the circuit of FIG. 2 one pixel at a time.

(2) The above-mentioned one pixel is averaged by the circuit shown in FIG. in the meantime,
A / D conversion of the next pixel is being performed.

(3) The above (1) and (2) are equivalent to one line,
Do it all.

(4) The above (1) to (3) are performed for each line. At this time, by averaging the images in the same column of the frame one after another, averaged data is obtained for each pixel of the line scanner.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS. This embodiment is shown in FIG.
This is an example in the case where a register is used as the storage means 4 of FIG.

FIG. 6 shows a circuit configuration of a second embodiment of the present invention. Elements 11 to 19 are the same as those of the first embodiment shown in FIG. 2, and a detailed description thereof will be omitted. Reference numeral 21 denotes a register (second register) corresponding to the storage unit 4 in FIG. FIG.
7 is a timing chart showing the contents of each signal of the embodiment circuit of FIG.

As can be seen with reference to FIGS. 3 and 7,
When the line memory 20 is used as the storage means as shown in FIG. 2, averaging is performed on the line data (line data) as described above, and the input signal A is also line data. When used, one point of data is averaged, and the input signal A is also one point of data. Also, when the line memory 20 is used, as described above, 1 / n, n
Although the coefficient of −1 / n is constant, when the register 21 is used as in this example, each time data is input, 1 / n,
The coefficient of n-1 / n is changed. That is, when the line memory is used, 1 / n, n-1 / n is updated after one line is completed, but when the register is used, 1 / n, n-1 / n are updated.
The value of the coefficient of n-1 / n is changed for each input data.

The peculiar effect of the present invention that the averaging process of the distortion data is performed simultaneously with the detection of the distortion data is that the line data is generally different from that of the second embodiment applied to the point data. Is larger in the first embodiment applied to

[0050]

As described above, according to the present invention,
Does not require extra memory, has an appropriate circuit size, and
Averaged data such as average distortion data can be obtained in parallel with the detection of distortion data without wasting operation time.

For example, averaging in the case where line data such as CCD reading, for example, there are several thousand pixels in one line, and it is desired to obtain average data for each pixel immediately after processing of the average number of lines is completed When performing processing, an average result is obtained faster than in the prior art. That is, since the average value of the distortion data for each pixel is obtained for the line data, if one line has 1000 pixels, for example, after the averaging operation, 1000 distortion average data are obtained at a time. On the other hand, in the prior art, the detected distortion data is written to the line memory as it is, and at the time of the averaging operation, the detected distortion data C is read from the line memory, and the previous addition data D is read from the other line memory. , C and D are performed without paralleling the distortion data detection.
The significant difference is that it requires extra memory and extra time to get the average result. Further, in the present invention, when multiplying the weighting coefficient, the input is switched and used, and the multiplication of the weighting coefficient is performed serially. Therefore, there is an advantage that only one multiplier is required.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing a basic configuration of the present invention.

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

FIG. 3 is a timing chart showing the contents of signals of the circuit of FIG. 2;

FIG. 4 is a conceptual diagram showing timings of main processing operations of the circuit of FIG. 2;

FIG. 5 is a schematic diagram showing the relationship between the line memory of FIG. 2, a line scanner, and the output of the line scanner.

FIG. 6 is a block diagram showing a circuit configuration of a second embodiment of the present invention.

FIG. 7 is a timing chart showing signal contents of the circuit of FIG. 6;

FIG. 8 is a block diagram illustrating an example of a configuration of a conventional averaging operation circuit.

FIG. 9 is a conceptual diagram showing timings of main processing operations of the circuit of FIG.

FIG. 10 is a timing chart showing the contents of signals of the circuit of FIG. 8;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 input selection means 2 multiplication means 3 addition means 4 storage means 11, 13 selector 12 multiplier 14 ROM 15 counter 16 magnitude comparator 17 control circuit 18 adder 19 register 20 line memory 21 register

Claims (10)

(57) [Claims] 1. An apparatus for averaging input signals sequentially read, comprising: an input selecting means for selecting and outputting an input signal and a stored value; a multiplying means for multiplying an output value of the input selecting means by a weighting coefficient; An adder for adding an output value of the multiplier, and a storage for storing an output value of the adder, wherein the input selector alternately selects an input signal and a storage value of the storage in a fixed cycle. When the input signal is selected, the multiplication means multiplies the output value of the input selection means by a weighting factor 1 / n (n is the number of times the input signal is read at that time). When a stored value is selected, the output value of the input selection means is multiplied by (n-1) / n as a weighting factor and output to the addition means, and the addition means outputs a pair of output values of the multiplication means. And outputs the result to the storage means. And an input signal averaging device. 2. The apparatus according to claim 1, wherein said adding means comprises a register for adding a pair of outputs serially output from said multiplying means and an adder.
3. An averaging device for an input signal according to claim 1. 3. The input device according to claim 1, wherein the storage unit is a line memory, and the input signal and the storage value selectively output from the input selection unit are line data. Signal averaging device. 4. The storage unit according to claim 1, wherein the storage unit is a register, and the input signal and the storage value selected and output from the input selection unit are each one-point data. Averaging device for input signal. 5. The method according to claim 5, wherein the weighting factor is 1 / in accordance with a count value n of the number of times the input signal is read by the input selecting means.
The multiplying means has weight coefficient generating means for generating n, (n-1) / n alternately, and further comprises the input selecting means until the value of n reaches a predetermined averaging count m.
5. The control device according to claim 1, further comprising a control unit that executes the averaging of the input signal by repeatedly performing each process of the multiplication unit, the addition unit, and the storage unit. Averaging device for input signal. 6. The input signal averaging device according to claim 1, wherein the input signal is a signal from a line scanner. 7. The input signal averaging apparatus according to claim 1, wherein the input signal is a distortion signal. 8. An input signal averaging device, comprising: a circuit for reading a signal containing various distortions, for removing a noise component which is a temporal variation component in the distortion component when detecting the distortion component. The input signal averaging apparatus according to claim 7, wherein the apparatus performs distortion data averaging processing. 9. A method of averaging sequentially read input signals, comprising: alternately selecting and outputting an input signal having a predetermined bit length and a storage value of a storage means in a constant cycle; and selecting the input signal. When the stored value is selected, the input signal is multiplied by 1 / n (n is the number of times of reading of the input signal at that time) and output. When the stored value is selected, the stored value is used as a weighting factor. Multiplying by (n-1) / n and outputting; multiplying by the weighting factor 1 / n and the weighting factor (n
-1) a step of adding a value multiplied by / n; and a step of storing the result of the addition in the storage means as the storage value, wherein each value is determined in advance by the value of n. An averaging method for an input signal, which is repeated until a predetermined number m is reached. 10. The input signal averaging method according to claim 9, wherein the input signal and the stored value are handled in units of line data or one point of data.