JPH03220533A - Data processor for camera - Google Patents

Abstract

PURPOSE:To securely prevent fatal failure caused by an abnormal correction value from occurring by previously setting a correction value for correcting an error quantity that an externally inputted measured value has and obtaining a correct measured value by correction arithmetic using the correction value. CONSTITUTION:For the measured value which is inputted from outside, the correction value for correcting the error quantity that the measured value has is set in advance and the correct measured value is obtained by the correction arithmetic using the corrected value. When the correction arithmetic is performed, the correction value read out of a storage means 12 is compared with a prepared specific data range and it is judged that only the value in the data range is the correction value, thereby performing the correction arithmetic. Consequently, the fatal failure of camera operation due to an abnormal correction value can securely be precluded.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a method for setting in advance a correction value for correcting the amount of error in a measurement value inputted from the outside, The present invention relates to a data processing device for a camera that obtains correct measured values through correction calculations using the correction values.

(Prior art) Recently, microcomputers (hereinafter referred to as
In addition, non-volatile memory (E 'FROM) came to be used.

By the way, various measured values are input into the camera in order to perform a predetermined photographing operation. For example, the battery voltage is input for battery check, the photometry value is input from the photometer circuit, the temperature measurement value is input from the temperature detection circuit, and the focus position corresponding to the zoom lens position at infinity in the focus lens is input. Ru. These measured values often have errors due to variations in the characteristics of the respective measurement circuits and variations in the mechanical parts. These errors can be known in advance by comparing them with standard values, so in order to correct these errors, adjustments are made using semi-fixed resistors, etc., and correction values are set to obtain correct values.

However, such adjustment work using a semi-fixed resistor or the like has poor workability, and also has problems in terms of reliability because the value changes due to vibration or changes over time.

Here, these adjustment amounts, ie, correction values, can be known in advance by comparison with standard values as described above. Therefore, in order to solve the above problem, this correction value is stored in the E2FROM, and when the camera is operated, this correction value is read out and a correction calculation is performed on the measured value to obtain the correct value. .

In this case, a microcomputer is used to read and write stored data to the E2FROM, but if this microcomputer goes out of control for some reason and writes by mistake, the stored data may be lost. This may destroy correction value data. That is, E'
A PROM enters a write mode by inputting a write code to an input terminal through clock synchronization. Therefore, if the E2PROM is equipped with an all-address erase or write mode, all the data will be erased, and if the E2PROM erases or writes only that address by specifying an address, the data at that address will be erased due to E' It is destroyed due to erroneous writing due to erroneous output to the FROM input terminal.

Here, as is well known, the E2FROM has a two-transistor configuration including a memory transistor and a selection transistor. An extremely thin oxide film of approximately 100 angstroms called a tunnel oxide film is formed on the drain region of the memory transistor, and electron injection into and erasure from the floating gate, which corresponds to data writing, is performed using this tunnel oxide film. This is done by passing a tunneling current. This ultra-thin oxide film may be destroyed by repeated writing and erasing, making writing impossible.

Furthermore, if the state of the floating gate portion changes due to static electricity, the stored data will be destroyed and changed to another value.

If the correction value data is destroyed in this way, when controlling the camera, the microcontroller will read the corrupted and erroneous data from the E2FROM and perform correction calculations based on this, which can cause major problems in camera operation. It ends up.

For example, if the correction amount stored in the E2FROM is a voltage adjustment amount for a battery check, the data portion of the adjustment amount that was previously written to the E2PROM in the assembly line process may be erroneously written due to a runaway of the microcomputer, resulting in a completely different data. Once the data is written, even if the microcontroller returns to normal operation by resetting the camera, incorrect data will be read from the E2FROM during correction calculations.
For example, even though the battery voltage is at a level sufficient to operate the camera, the correction calculation may result in a value that is much smaller than the actual value. For this reason, the microcomputer mistakenly judges that there is no battery voltage at all by comparing it with the comparison voltage data for voltage check, and as a result, all operations of the camera are prohibited.

Therefore, even if a new battery is inserted, there is a risk that the camera will not work at all.

(Problem to be solved by the invention) As mentioned above, even though the correction value is originally provided to correct errors, if an incorrect value is written due to a runaway of the microcomputer, etc., the camera This will cause serious problems in the operation as described above.

An object of the present invention is to provide camera data that can reliably prevent the occurrence of fatal defects due to abnormal correction values by using the read correction values as correction values only when they are normal during correction calculations. The purpose of this invention is to provide a processing device.

[Structure of the invention]

(Means for Solving the Problems) A camera data processing device according to the present invention sets in advance a correction value for correcting the amount of error that the measurement value has for a measurement value inputted from the outside, and sets this correction value in advance. The correct measurement value is obtained by the correction calculation used, and the correction value is determined from the variation range of the error amount. The correction value is compared with a predetermined data range prepared in advance, and if the correction value is within the data range, the correction value is determined to be valid, and the correction value is performed.

(Function) The present invention focuses on the fact that errors in measured values occur due to variations in the characteristics and mechanical parts of the measurement circuit from camera to camera, and that they fall within a predetermined range, and performs correction calculations. At this time, the correction value read from the storage means is compared with a predetermined data range prepared in advance, and only those that fall within this data range are judged to be valid as correction values, and correction calculations are performed. There is. Therefore, fatal malfunctions in camera operation based on abnormal correction values can be reliably prevented.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, reference numeral 11 denotes a microcomputer, which centrally controls the operation of the entire camera in response to various externally input signals, measured values, and the like. It also includes a correction calculation means to be described later. SWl is a main switch, and by turning it on, the camera can be controlled by the microcomputer 11. SW2 is a first release switch, which is turned on in the first stage when the photographer presses a release button (not shown) to perform focusing and metering operations via the microcomputer 11. SW3 is a second release switch, which is turned on in the second stage after the first release switch SW2 is turned on by the pressing operation of the release button, and is caused to perform a shutter exposure operation via the microcomputer 11.

Reference numeral 12 denotes a storage means using a non-volatile memory (E2PROM), into which correction values for various measured values input to the microcomputer 11 are written during the assembly line process by a method described later.

As mentioned above, various measured values are input to the microcomputer 11, and the battery voltage input for power check will be explained below as a representative example.

Reference numeral 13 denotes a battery voltage detection circuit, which divides the voltage applied to the input terminal 13i by resistors R1 and R2 and inputs it to the A/D converter 15. The A/D converter 15 receives the analog voltage V1 from the battery voltage detection circuit I3 and the A/D converter 15.
Reference voltage from D converter reference voltage source 16■71. is input, the analog voltage V+ is A/D converted based on the reference voltage V +el, and the digital output thereof is input to the microcomputer 11 as a battery voltage value.

The input terminal 13i of the battery voltage detection circuit 13 is connected to a reference voltage source 14! during the camera assembly line process.
is connected. Further, in the camera specification state, the battery 14b for normal power supply is connected.

18 bits only memory (hereinafter referred to as ROM),
It is built into the microcomputer It, and includes standard value data for setting correction values (described later) in the assembly line process, and predicted data ranges for determining the quality of the correction values when using the camera, etc. There is.

Reference numeral 19 denotes a display device such as a liquid crystal display (LCD), which displays this when a correction value invalidation state, which will be described later, occurs.

Next, the operation will be explained using the flowcharts of FIGS. 2 and 3.

First, in the assembly line process, E2PROM12,
The case of setting the correction value for the battery voltage will be explained with reference to FIG.

In the assembly line process, a reference voltage source is connected to the input terminal 13i of the battery voltage detection circuit 13, and the reference voltage V is set. (Step 201).

As a result, the battery voltage detection circuit 13 outputs an analog voltage VIB determined by the following equation (step 2
02).

This analog voltage V, is converted to A by the A/D converter 15.
It is converted into a digital value BC1 based on the /D conversion reference voltage V t e l and inputted to the microcomputer 11 (step 203).

In the built-in ROM +8 of the microcomputer 11, standard value data BCO for setting correction values is preset as described above. This standard value data BCQ is the reference voltage V when the voltage dividing resistor RI R2 of the battery voltage detection circuit 13 has a standard value without variation. The analog voltage V IA produced for the same standard A
/D conversion reference voltage V11. This is a digital value that should be obtained by standard A/D conversion operation.

The microcomputer 11 sets the reference voltage V in step 203.

When the digital value BCI, which is the measured value of , is input, the difference ΔBCI between this digital value BC1' and the standard value data BCO is determined (step 204). This difference ΔB
CI, that is, the error that the measured value has, is determined by the battery voltage input section, that is, the battery voltage detection circuit 13 and the A/
This is caused by variations in the characteristics of the D converter 15, and will naturally occur in the measured values of the power supply battery when used as a camera, so this difference ΔBCI can be used to calculate II.
) By correcting the measured value, it is possible to obtain a correct value that is not affected by the above-mentioned variations. Therefore, this difference △BC1
is the correction value for the battery voltage in E2FROM.
+2 is written (step 205), and the correction value setting operation in the assembly line process is completed.

Here, as mentioned above, the difference ΔBCI is caused by variations in the characteristics of the battery voltage detection circuit 13 and A/D converter 15, and is a unique value for each camera, but it may vary greatly from camera to camera. There is no difference ΔBCI,
That is, the value of the correction value should fall within a certain range. The fact that it does not fall within this range means that the data portion of the correction value that was written in advance in the assembly line process is erroneously written due to the aforementioned runaway of the microcomputer 11, etc.
This means a so-called data destruction state where completely different data has been written. If measured values are corrected using such corrupted data, there is a risk of fatal malfunctions in camera operation, and this must be definitely eliminated.

Therefore, in the present invention, a predetermined data range for determining the quality of the correction value is set in the ROM 18, and prior to the measurement value correction calculation when using the camera, which will be described later.
It is determined whether the correction value is valid or not based on the above data range.

The above data range is determined, for example, as follows. That is, the maximum and minimum values of the variation values of the characteristics of the battery voltage detection circuit 13, A/D converter 15, etc. are determined, these are set as ±ΔBCO with respect to the standard value, and the absolute value Δ
Set BCO to ROM+8 as the data range.

Next, the operation when using the camera will be explained with reference to FIG. First, when the main switch SW1 is turned on (step 301), the microcomputer 11
Correction value data ΔBCI for battery voltage from OMI2
(Step 3o2).

Then, in steps 303 and 304'), the correction value data Δ is compared with the data width ΔBCO prepared in advance.
If BCI is within the data width △BCO, that is, if 1△BCI +≦△BCO, this data △B
CI is determined to be valid as a correction value for battery voltage. On the other hand, if it is not within the data width ΔBCO, that is, if the determination in step 304 is NO, this correction value ΔBC1 is invalid, so ΔBC1=O is set (step 305), and the display A display command is issued to the device 19 to notify the malfunction (step 306).
).

Here, the display 19 displays various indications such as the numerical value of the film counter on the LCD according to commands from the microcomputer 11. For example, as a malfunction display indicating that the correction value ΔBCI is invalid, Make the frame surrounding the numerical display part of the counter blink.

Next, when the photographer presses the release button and the first release switch SW2 is turned on (step 307), the voltage of the power supply battery +4b is input to the microcomputer 11, and the value obtained by subtracting the correction value ΔBCI from the input value is input. and perform a battery check based on this value (step 3).
08,309). If the battery voltage after this correction is not lower than the release lock voltage, the second release switch SW3 is turned on (step 310), and the shutter operation is performed (step 3).
11). On the other hand, if the corrected battery voltage is below the release lock voltage, no shutter operation is performed even if the second release switch SW3 is turned on.

Here, the data range ΔBCO can be set to about 10% of the release lock voltage or battery warning voltage. In other words, from the resistance value tolerance of ±5% of the voltage dividing resistors R1 and R2 of the battery voltage detection circuit 13, the tolerance of the A/D conversion reference voltage ±3%, and the A/D converter accuracy ±1%, the total A variation of approximately ±10% can be expected. Since the data range can be set to about 10% in this way, if the correction value ΔBC1 is effective, an accurate battery check can be performed. In addition, even if the correction value ΔBCI does not fall within the data range ΔBCO and becomes invalid, resulting in ΔBCI-〇, the battery can be checked with an accuracy within about 10% of the actual battery voltage, which can be fatal to camera operation. It will not cause any trouble. Furthermore, this correction value Δ
Since the invalid state of the BCI is displayed on the display 19, the user can be informed of this.

The above explanation is for the case of battery check, but other correction values for the temperature detection circuit and photometry circuit, correction amounts corresponding to the zoom lens position at infinity in the focus lens, etc. can also be determined by the same means. In addition to preventing fatal malfunctions in camera operation, this can be displayed on an LCD or LED to notify the user.

〔Effect of the invention〕

As described above, according to the present invention, even if the data stored in the storage means during the assembly line process becomes erroneous data due to erroneous writing due to a runaway of the microcomputer, data destruction due to static electricity, etc., this erroneous data can be saved. Since it is possible to detect and reliably prevent its use, there will be no fatal malfunction in camera operation.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of a camera data processing device according to the present invention, and FIGS. 2 and 3 are flowcharts explaining the operation of the device shown in FIG. 11. A microcomputer having a correction calculation means as a function, 12. A storage means, 18. A ROM in which a predetermined data range is prepared.

Claims (1)

[Claims] (1) Camera data in which a correction value is set in advance to correct the amount of error in the measurement value input from an external source, and a correct measurement value is obtained by a correction calculation using this correction value. In the processing device, means for storing the correction value; and comparing the correction value read out to perform the correction calculation with a predetermined data range prepared in advance determined from the variation range of the error amount; A data processing device for a camera, comprising: a calculation means that determines that the correction value is valid if it is within the data range, and performs the correction calculation.