JPS60177331A - Camera shake detection device - Google Patents

Abstract

PURPOSE:To detect a camera hand-shake and to warn it by sampling and processing the output signal of a CCD line sensor. CONSTITUTION:Information on the shutter speed and aperture value at the point I of time when a shutter button is pressed is sent from a terminal 7 to a driving circuit 2, which drives the CCD line sensor 1 to send an output picture signal A to signal processing circuits 3 and 8. The circuit 8 inputs the information on the shutter speed and aperture value from the terminal 7 to calculate the difference between a maximum and a minimum level from the output signal of the sensor 1 and determine the number (n) of opicture elements, and calculates and sends the maximum level of a signal A at which said data is at least obtained to the circuit 3 as a threshold value L1. The circuit 3 samples part of the signal A above the threshold value L1 to obtain a signal B. The output picture signal C of the sensor 1 at the point II of time set after the point I of time is sent to the circuit 3 and sampled on the basis of a threshold value L2 obtained similarly to the threshold value II to obtain a signal D. The shifting extent of the signal D when the correlation calculated from the signals B and D is maximum corresponds to the picture blur amount generated between the points I and IIof time.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a camera shake detection device for detecting camera shake during photographing of a camera, particularly a still camera.

Some conventional still cameras display a camera shake warning when shooting at a shutter speed slower than a certain shutter speed, but this is simply a mechanical warning. However, it was not possible to know whether or not there was actual camera shake. Furthermore, when taking pictures at a relatively fast shutter speed, there is no camera shake warning, and even if there is actual camera shake, the photographer does not notice it and does not have to take the picture again, often resulting in failures due to camera shake. Ta.

It is an object of the present invention to provide a camera shake detection device which can improve such problems and detect whether or not there is camera shake during photographing, and notify the photographer immediately after photographing. , the gist of which is that the CC is placed at a position optically equivalent to the film surface and outputs image signals at different times set in response to the action of pressing the shirt button.
a D-line sensor, a circuit that determines a threshold value for sampling a signal including a number of pixels determined by output image signal information of the CCD line sensor and shutter speed/aperture value information, and a circuit that samples the two image signals using the threshold value. , and a circuit that calculates the amount of image blur between the different time points by calculating the amount of correlation between these sampling signals.

The present invention will be explained in detail below based on illustrated embodiments.

FIG. 1 shows an embodiment of a camera shake detection device according to the present invention, in which a CCD line sensor 1 that receives a subject image through an optical system, its drive circuit 2, and an output image signal of the CCD line sensor 1 are sampled. A first signal processing circuit 3 that performs processing and performs a correlation calculation, a determination circuit 4 that determines the magnitude relationship between the image blurring ratio based on the correlation calculated by the first signal processing circuit 3 and the set blurring E; a drive circuit 5 for displaying a warning to the photographer when the image blur amount is larger than the set blur amount E based on the output from the determination circuit 4;
The light emitting diode 6 operated by this drive circuit 5 receives the camera's shutter speed and aperture information from the terminal 7, and also inputs information about the difference between the maximum level and minimum level of the output signal from the CCD line sensor 1. to determine the number n of pixels, and determine first and second thresholds L1 and L2 corresponding to the first time point and the second time point for extracting a signal containing at least n number of pixels. A second signal processing circuit 8 inputs information on the enlargement magnification when printing from a negative film from a terminal 9 before photographing, and determines a set blur amount E.
The signal processing circuit 10 is comprised of a signal processing circuit IO. The terminal 7 is also connected to the drive circuit 2, and information on the shutter speed and aperture value is obtained from the terminal 7 to determine the optimum accumulation time for the CCD line sensor 1.

FIG. 2 shows the output image signal from the CCD line sensor 1 and its sampling signal, and the signals (A),
(C) is the output image signal at the first and second time points, respectively, and signals (B) and (D) are the output image signals (
A) and (C) represent sampling signals at a level equal to or higher than the threshold L1.12.

Furthermore, FIG. 3 shows an example of the optical system of a single-lens reflex camera that performs this blur detection, in which the light beam entering the photographic lens 11 passes through the quick return mirror 12 and is installed on the back of the quick return mirror 12. The light is reflected by the anti-fouling mirror 13 and guided to the CCD line sensor 1 provided at the bottom of the camera box.

The part of the quick return mirror 12 that passes light to the reflection mirror 13 is a half mirror with a transmittance of about 50%, and the remaining part is a complete reflection mirror. Further, 14 indicates a film, and 15 indicates a pentaprism.

Although a plurality of CCD line sensors 1 are used, FIG. 4 shows an example of the arrangement when two CCDCC line sensors 1b are used, and FIG. 5 shows an example of the arrangement using three CCD line sensors 1a, An example of arrangement when using b and 1c is shown.

The operating principle of this embodiment will be explained below.When photographing a subject, pressing the shutter button on the camera sets a first point in time, and information on the shutter speed and aperture value at this first point is sent to the terminal 7. is sent from CC to the drive circuit 2 as described above.
The optimal storage time for the D line sensor 1 is determined. Then, the CCD line sensor 1 is driven by the drive circuit 2, and its output image signal, that is, the signal (A) shown in FIG. 2 is sent to the first signal processing circuit 3 and the second signal processing circuit 8. In the second signal processing circuit 8, information on the shutter speed and aperture value is inputted through the terminal 7, and the difference between the maximum level and the minimum level is determined from the output signal of the CCD line sensor 1 to determine the number of pixels n. If the storage time of the CCD line sensor 1 is long, the output signal of the CCD line sensor 1 will also be a blurred image signal, and if the difference between the maximum level and the minimum level of the output signal is small, it will be possible to capture a subject with little brightness change. In this case, the number of pixels n
must be a large value. Therefore, the number of pixels n is determined from the information on the shutter speed and the aperture value and the value of the difference between the maximum level and the minimum level of the output signal of the CCD line sensor 1, and is 10 to 100% of the total number of pixels.

Further, in the second signal processing circuit 8, the maximum level of the signal (A) at which data of a predetermined number of pixels is at least equalized is determined as a first threshold L1, and this first threshold Ll
is sent to the first signal processing circuit 3. Then, the signal processing circuit 3 samples the signal (A) equal to or higher than the first threshold value L1 to obtain the sampling signal (B) shown in FIG. 2.

If the second time point is set after the first time point, the amount of image blur between the first and second time points will be measured. The readout of the signal at the second time point is similar to the first time point, but
The output image signal (C) shown in FIG. 2 of the CCD line sensor l at this second time point is transmitted to the first signal processing circuit 3, and the output image signal (C) shown in FIG. When sampling is performed using the second threshold value L2 obtained in this manner, a sampling signal (D) shown in FIG. 2 is obtained.

That is, the number n of pixels determined by the information on the shutter speed and aperture value at the first time point and the information on the difference between the maximum level and minimum level of the output image signal of the CCD line sensor 1 is transmitted to the second signal processing circuit 8. When the maximum level of the signal (C) from which data for at least n pixels is obtained is sent to the first signal processing circuit 3 as the second threshold L2, the signal obtained by the first signal processing circuit 3 ( C) is the second threshold value, and two or more levels are sampled to obtain the signal (D).

The sampling signal (B) obtained in this way,
According to (D), the amount of correlation is calculated using the correlation function shown in the following equation. That is, the correlation amount is 5(X), k is the pixel number of the COD line sensor, B(k) and D(k) are the sampling signals (B), and the output of the pixel number of (1)) is 16, and X is The shift amount is expressed as follows.

5(X)=Σ-B(k)-D(k,x)where x=
O1±1, ±2.1... Here, D(k, 0) is equal to D(k), and D(k, l
) represents a signal obtained by shifting D(k) by one pixel as a whole. Further, the sign of X indicates the shift direction, and minus indicates the opposite direction to plus.

This corresponds to the shift amount X of the signal (D) when the correlation amount 5(x) becomes maximum, or the amount of image blurring that occurs between the lth time point and the man 2 time point. The determination circuit 4 compares the magnitude relationship between the image blur amount calculated in the first signal processing circuit 3 and the set blur amount E, and if the image blur amount exceeds the set blur amount E, the drive circuit 5 emits light. The diode 6 is turned on to warn the photographer.

The set shake amount E corresponds to the allowable shake amount on the negative film surface, and this allowable shake amount changes depending on the enlargement magnification from the negative film to the print. For example, if the allowable amount of blur on the negative film surface for a service version print is 75 μm, the allowable amount of blur on the negative film surface for a cabinet version print, which is about twice that amount, is 377 zm. varies depending on the enlargement magnification for printing. The set blur amount E is determined before shooting by inputting information on the enlargement magnification when printing from negative film to the third signal processing circuit IO via the terminal 9, and inputting it to the determination circuit 4 in advance. being sent. Note that this information on the enlargement magnification can be obtained by the photographer operating a switch provided on the outside of the camera, for example, before photographing.

For example, the image blur amount obtained by the first processing circuit 3 is
It will be seen in each direction of the CCD line sensors 1a and 1b in the figure. Of course, assuming that the CCD line sensor 1 is one piece,
If it is known in advance that the amount of image blurring is particularly large in the direction in which the shirt button is pressed, for example, it may be arranged only in that direction. Furthermore, if three CCD line sensors 1 are used as shown in FIG. 5, image blur resolved along three directions can be measured.

In addition, the above-mentioned embodiment also has an image blur h between the first and second time points.
”, image signals from the CCD line sensor 1 at the third and fourth time points in addition to the second time point are read out,
By calculating the image blur information between the first and third and the first and fourth time points, it is possible to measure the amount of blur in one image as a function of time. Further, although the setting blur E is determined based on the enlargement magnification, it may be set to a constant value in consideration of enlargement to a normal service version print.

The CCD line sensor 1 is not limited to the position shown in FIG. 3, but can form an image using a lens at any other position as long as the distance is optically equal to the film surface. Furthermore, the CCD line sensor 1 can be placed outside together with other lenses without using the photographing lens 11. Furthermore, although a light emitting diode is used in the embodiment as a warning display means for camera shake, in addition to the warning by a light, it is also possible to give a warning by sound, text, etc.

As explained above, according to the camera shake detection device according to the present invention, by sampling and processing the output signal of the CCD line sensor, camera shake can be detected through quick calculation and a warning can be given to the photographer. If there is camera shake, the photographer can immediately take the picture again after receiving the warning, and can recover from the failure caused by the camera shake. It is also possible to store the direction and components of camera shake in a memory and effectively utilize the data, for example, when performing blur correction after image blur is detected.

[Brief explanation of the drawing]

The drawings show an embodiment of the camera shake detection device according to the present invention, and FIG. 1 is a block circuit diagram thereof, and FIG.
The figure is a waveform diagram of the output signal of a CCD line sensor and its sampling signal, Figure 3 is an optical system diagram of an example of the arrangement of CCD line sensors in a camera, and Figures 4 and 5 are an example of the arrangement of multiple CCD line sensors. It is an explanatory diagram. Symbols l, 1a, ■b, and 1c are CCD line sensors, 2 is a drive circuit, 3.8.10 is a signal processing circuit, 4 is a determination circuit, 5 is a drive circuit, 6 is a light emitting diode, 11 is a photographic lens, 12 is a quick return mirror, and 13 is a reflection mirror. Patent applicant Canon Co., Ltd. Representative Patent attorney Masaru Hibiya dゝFigure 1Figure 2

Claims (1)

[Claims] 1. A CCD line sensor that is arranged at a position optically equivalent to the film surface and outputs image signals at different times set in response to the action of pressing the shirt button; A circuit that determines a threshold value for sampling a signal including the number of pixels determined by sensor output image signal information and shutter speed/aperture value information, and a circuit that samples the two image signals using the threshold value and correlates these sampling signals with each other. and a circuit for calculating the amount of image blur between the different time points by calculating the amount of image blur between the different points in time. 2. The camera shake detection device according to claim 1, wherein the threshold value is determined by a difference between a maximum level and a minimum level of output image signal information of a CCD line sensor. 3. The camera shake detection device according to claim 1, wherein the image blur amount is a shift amount between image signals when the correlation amount becomes maximum. 4. The camera shake detection device according to claim 1, wherein the integration time of the CCD line sensor is determined based on information on shutter speed and aperture value. 5. The camera shake detection device according to claim 1, further comprising means for displaying a warning to the photographer when the calculated image shake amount exceeds a set shake amount. 6. The camera shake detection device according to claim 5, wherein the set shake amount is determined based on information on an enlargement magnification when printing from a negative film. 7. The camera shake detection device according to claim 1, wherein the CCD line sensor is arranged in a plurality of directions, and the image blur amount in the plurality of directions is detected.