JP4248536B2 - Measuring method and apparatus for mounting position of pixel surface and mat surface in single lens reflex digital camera - Google Patents

Description

  The present invention measures the actual mounting position of a pixel surface formed with an image sensor like a digital single-lens reflex camera and a mat surface on a finder optical path formed at a position conjugate to the pixel surface. In particular, the present invention relates to a measurement method that can determine whether or not there is an error in the attachment positions of a pixel surface and a mat surface, and an apparatus for the same.

  The pixel surface on which the image sensor of a single-lens reflex digital camera is provided and the mat surface on the finder optical path that presents an image to be photographed to the photographer's eyes are a conjugate point at the focal point of the objective lens of the camera. It must be provided as However, because both the pixel surface and the mat surface are artificially assembled and mounted in a structure called a camera body, the pixel surface and the mat surface itself can be manufactured no matter how accurate the drawing is. It is inevitable that errors and mounting errors occur. However, even if the generation of errors is unavoidable, the range must be within an allowable range.

  Conventionally, regarding the above problems, it is impossible to simultaneously measure the positional accuracy of the pixel surface and the mat surface, or the positional error of both by the same measuring means, and the respective mounting accuracy can be individually measured by individual means. The present situation is that the error between the attachment positions of the pixel surface and the mat surface is determined based on the results of the measurement of the attachment position of the pixel surface and the mat surface.

  However, if the pixel surface and the matte surface are individually measured as described above, not only the measurement is troublesome, but there is not one measurement origin in each measurement, so an error caused by that is newly added. As a result, there is a problem that position measurement with fundamentally high accuracy on the pixel surface and the mat surface is extremely difficult to realize.

The inventor of the present invention previously described a method and apparatus for measuring the flatness of a pixel surface that can also measure the accuracy of the mounting position of a pixel provided with an image sensor such as a CCD or CMOS of a single-lens reflex digital camera. However, the measurement method of the present invention cannot measure the mat surface mounting position.
Japanese Patent Application No. 2004-261655

  Therefore, in the present invention, the pixel surface on which the image sensor of the single-lens reflex digital camera is provided and the matte surface on which the image to be photographed is displayed are provided as conjugate points at the focal point of the objective lens of the camera. It is an object of the present invention to provide a measurement method and a measurement apparatus that can measure whether or not the two attachment positions are accurate and error instantaneously by measuring the same in the same measurement process.

The configuration of the method for measuring the mounting position of the pixel surface and the mat surface according to the present invention, which has been made for the purpose of solving the above-mentioned problems, is a chart pattern image from a reference point with the pixel surface and the mat surface in a single-lens reflex digital camera as target surfaces. When the optical path of the pattern image is switched by the shutter mirror of the camera and is imaged through the objective lens at the measurement point set on the two target surfaces, the objective lens is moved back and forth to reflect the image from the measurement point. Is detected photo-electrically at the conjugate point of the reference point, and the actual mounting positions of the pixel surface and the mat surface are measured based on the detection value when the contrast of the reflected image is the strongest. Is.

  In the above measurement method, when the chart pattern image is formed on the pixel surface, the shutter mirror of the camera is placed in the raised position, and when the image is formed on the matte surface, the shutter mirror is lowered. The position of the shutter mirror is determined by arranging a sensor such as a light receiving / emitting type on the reflecting surface of the mirror and determining whether or not the reflected light from the mirror is presented to the sensor. That is, when the reflected light from the shutter mirror is presented to the sensor, the mirror is in a fixed position, and when the reflected light from the mirror is not presented to the sensor, the mirror is in the raised position. Therefore, the image data detected when the shutter mirror is raised is data based on the image on the pixel surface, and the image data detected when the mirror is lowered is the image on the mat surface. It is determined that the data is based on.

  In addition, the configuration of the apparatus for carrying out the measurement method includes a collimator lens, a chart pattern including a light source behind the collimator lens, and an objective lens disposed on the parallel light emitting side of the collimator lens. An objective lens for forming the pattern image on the pixel surface and mat surface of a single-lens reflex digital camera set for measurement, and a mirror position for detecting the upper and lower positions of the set shutter mirror of the camera An optical-electrical detection in which the optical path of the reflected image reflected from the sensor and the pixel surface and the mat surface is deflected on the focal side passing through the collimator lens and arranged at the conjugate point of the collimator lens on the deflection optical path. The pixel surface and the matte surface when the shutter mirror of the set camera is moved up and down Light from each of the reflected image - is characterized in the provision of the position data processing means for processing the electrical signals of the position data obtained are electrical conversion.

  In the single-lens reflex digital camera, the pixel surface formed by the image sensor and the mat surface where the finder image is connected can be measured in the same measurement process using the same measuring means. The pixel surface mounting position and its error, and the mat surface mounting position and its error, which could not be measured by the prior art, can be measured by a single measuring means in the same measurement process.

  Next, an example of an embodiment of the measurement method of the present invention will be described with reference to FIG. 1 schematically showing an optical configuration example of the measurement apparatus of the present invention.

  In FIG. 1, 1 is a collimator lens, 2 is a chart pattern arranged at the focal point of the lens 1, and 3 is a light source disposed behind the pattern 2, and in the example shown, light emitted from the light source 3 Enters the collimator lens 1 as an image of the chart pattern 2 (hereinafter also referred to as a pattern image 2), is converted into a parallel optical axis, and is emitted toward an objective lens 4 described later.

  The objective lens 4 arranged on the output optical axis side of the collimator lens 1 is arranged to be supported by a lens support 5 that can move along the optical axis of the collimator lens 1 in increments of 0.1 μm, for example. Reference numeral 6 denotes a focal position of the objective lens 4, and the focal position 6 is a reference mounting position of the pixel surface Pe by an image sensor such as a CCD or CMOS in a single-lens reflex digital camera whose position accuracy is to be measured. A measurement point on the measurement target surface is set at the center. Hereinafter, the pixel surface Pe attached at the reference attachment position (focal point position 6) is defined as a first measurement target surface Oj1. A set portion 7 of the body CB of the single-lens reflex digital camera provided with the first target surface Oj1 is formed on the front surface side of the objective lens 4.

  The body CB set in the set unit 7 has a first target surface Oj1 attached as a pixel surface Pe, a flip-up shutter mirror Sm, and an optical path passing through the pentaprism Pm of the finder Fi. A focus mat surface Mp for forming a finder image at a focal point of the objective lens 4 via the mirror Sm, that is, a conjugate point with the pixel surface Pe, is attached as a second measurement target surface Oj2. In the body CB, Fp is an optical filter disposed in front of the pixel surface Pe (target surface Oj1), and Lm is a lens barrel for an interchangeable lens mount. The position of the measurement point on the first target surface Oj1 is, in principle, the center of the pixel surface Pe, but is not limited to this, and can be arbitrarily set or changed.

  The objective lens 4 is provided so as to be supported by the lens support 5 as described above. The support 5 is mounted on a precision moving table 8 having a length measuring means such as a linear encoder. The objective lens 4 is provided so as to be movable back and forth in parallel with the parallel optical axis of the collimator lens 1. As an example, the moving unit of the moving table 8 may be about 0.1 μm to 1 μm.

  Reference numeral 9 denotes a mirror detection sensor disposed above the objective lens 4 in the lens support 5 toward the shutter mirror Sm in the body CB. Here, a light receiving / emitting type sensor is used as an example, and the mirror Sm is shown in the figure. When in the solid line position, the light emitted from itself is reflected by the mirror Sm and outputs an electrical signal. When the mirror Sm jumps up and is at the position of the phantom line in the figure, the light from the sensor 9 is Since no electrical signal is output because the light is not reflected, the presence or absence of a signal from the sensor 9 makes it possible to determine whether the position of the shutter mirror Sm is up or down.

  Reference numeral 10 denotes a beam splitter disposed on the diverging optical axis on the focal side (light source side) of the collimator lens 1, and the pattern imaged on the two target surfaces Oj1 and Oj2 reflected through the objective lens 4 This is for deflecting the optical axis of the reflected image of image 2 by 90 degrees.

  Reference numeral 11 denotes an optical-electrical conversion element (hereinafter referred to as an optical-electrical sensor) disposed on the reflection optical axis of the splitter 10 and at a conjugate point with the focal point of the collimator lens 1 as described above. The configuration from the collimator lens 1 to the photoelectric sensor 11 forms an example of the optical configuration of the measuring apparatus of the present invention.

  Assuming that the two target surfaces Oj1 and Oj2 whose mounting position and accuracy (error) are to be measured are provided without error, the light receiving surface is at the focal position 6 on the straight optical axis of the objective lens 4. Each of the pattern images 2 by the pixel surface Pe (first target surface Oj1) attached without error and the second target surface Oj2 (matte surface Mp) attached without error to the focal position of the objective lens 4 through the shutter mirror Sm. Since the reflected image has the highest contrast, the output value of each photoelectric sensor 11 that receives this reflected image shows the same peak value. At this time, if the objective lens 4 is slightly moved back and forth by the lens support 5, the output value is It becomes smaller than the peak value.

  Here, if there is an attachment error in which one of the target surfaces Oj1 and Oj2 or both of the attachment surfaces do not coincide with the focal position 6 of the objective lens 4, the surface Oj1 and / or Oj2 is connected. Since the pattern image 2 to be imaged is in a so-called “out-of-focus” state, the output of the photoelectric sensor 11 that receives the reflected image is the focused image (the reflected image of the surface Oj1 or Oj2 without error). Becomes smaller than the peak value output of the photoelectric sensor 11 that has received light.

  Therefore, in the measurement of the mounting positions of the two target surfaces Oj1 and Oj2 according to the present invention, the target surfaces Oj1 and Oj2 are moved so that the output of the photoelectric sensor 11 corresponding to each measurement point becomes a peak value. The lens support 5 of the table 8 is finely moved back and forth to finely move the objective lens 4 back and forth, and the amount of movement of the objective lens 4 when the output related to each surface of the photoelectric sensor 11 shows a peak value is detected. Since this movement amount indicates an attachment error with respect to the reference attachment position of the target surfaces Oj1 and Oj2, this movement amount is detected for each of the target surfaces Oj1 and Oj2.

  In the measurement of the mounting positions of the target surfaces Oj1 and Oj2, the peak output values of the reflected images on the two target surfaces Oj1 and Oj2 obtained by the photoelectric sensor 11 are objective with respect to the reference mounting position (focal position 6). The distance obtained by moving the lens 4 is detected by the movement distance, and the target surfaces Oj1 and Oj2 are allowed by comparing the detected distance with a preset tolerance value. It can be discriminated whether or not it is mounted within the mounting error. In addition, the respective attachment positions of the two target surfaces Oj1 and Oj2 or the mounting errors are compared and processed to determine whether the mounting errors of the two target surfaces Oj1 and Oj2 are within the allowable values. Determine whether each of the two target surfaces Oj1 and Oj2 is within the accuracy of a predetermined mounting position, or whether the position error between the two target surfaces Oj1 and Oj2 is within an allowable value. To do. As a result, in the measurement method described above, the data of image formation by the first target surface Oj1 with the shutter mirror Sm raised, and the data of image formation by the second target surface Oj2 with the mirror Sm lowered, It can be obtained by the same measuring means in one measuring step.

  Next, an example of data handling and data processing in the measurement apparatus will be described with reference to the block diagram of FIG. The moving table 8 on which the objective lens 4 is mounted on the lens support 5 and can be moved back and forth in fine units, the moving data is detected by the counter 8b from the linear encoder 8a provided in the moving table 8 as a pulse signal of the distance.

  On the other hand, with respect to the photoelectric sensor 11, the pixel surface Pe (first target surface Oj1) is arranged without error at the focal position 6 of the objective lens 4, and the mat surface Mp (at the focal position via the shutter mirror Sm). When the second target surface Oj2) is arranged without error, the photoelectric sensor 11 receives the strongest contrast of the reflected image of the chart pattern image 2 formed on the first target surface Oj1 by raising the mirror Sm. The position of Oj1 at this time is stored in the arithmetic processing unit 12 as a reference value at this measurement point (Oj1). Then, the mirror Sm is lowered, and the calculation processing is performed using the position of Oj2 when the photoelectric sensor 11 receives the strongest contrast of the reflected image formed on the second target surface Oj2 as a reference value at the measurement point Oj2. Stored in section 12.

  Next, the camera body CB having two target surfaces Oj1 and Oj2 to be measured is set in the setting unit 7, and the shutter mirror Sm is raised and lowered with respect to the two target surfaces Oj1 and Oj2. In this state, the chart pattern image 2 is formed, and in this state, the objective lens 4 is finely moved back and forth, and the contrast of the reflected image in the meantime is sequentially detected by the photoelectric sensor 11, and thus the objective lens 4 is moved back and forth. The position of the objective lens 4 when the respective outputs related to the two target surfaces Oj1 and Oj2 obtained by the sensor 11 show a peak value when the position is slightly moved is different from the position of the objective lens 4 at the reference value. Is calculated in the arithmetic processing unit 11.

  In this way, the output value of the photoelectric sensor 11 by the image formation at the measurement points of the two target surfaces Oj1 and Oj2 in the actual camera body CB is sequentially detected while finely moving the objective lens 4 back and forth. Depending on the position of the objective lens 4 at the peak value obtained, each measurement point (surface) of the two target surfaces Oj1 and Oj2 is relative to a reference mounting position (focal position 6) that is assumed to be ideally mounted without error. It is possible to detect the size of the mounted error. In FIG. 2, 13a is a D / A converter for a command value for the moving drive source (motor M) of the moving base 8, and 13b is an amplifier. 14a is an amplifier for amplifying the detection value of the photoelectric sensor 11, and 14b is an A / D converter.

  The present invention is as described above. A pixel pattern and a matte surface in a single-lens reflex digital camera are used as target surfaces, and a chart pattern image is emitted from a reference point, and imaged through an objective lens at measurement points set on the two target surfaces. The objective lens is moved back and forth to photo-electrically detect the reflected image from the measurement point at the conjugate point of the reference point, and based on the detected value when the contrast of the reflected image is strongest Since it is possible to measure the difference between the actual mounting position of the pixel surface and the mat surface and the reference mounting position, the mounting position of the pixel surface and mat surface of the single-lens reflex digital camera and the measurement of the mounting error can be measured with one measuring device. It can be carried out extremely rationally and labor-saving in one measurement process.

  Further, in the present invention, once the body of a single-lens reflex digital camera is mounted on a measuring device, the mounting position of the pixel surface and the mounting position of the mat surface can be measured by this measuring device. However, not only does the measurement error due to having to repeat the mechanical attachment / detachment operation occur, but also the measurement accuracy of two measurement objects can be improved at the same time.

The schematic diagram which showed the 1st example of the optical structure of this invention apparatus. The block diagram of an example of the signal processing system in this invention apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Collimator lens 2 Chart pattern 3 Light source 4 Objective lens 5 Objective lens support 6 Focus position 7 Camera body setting part
Sm Shutter mirror 8 Moving table 9 Mirror detection sensor
10 Beam splitter
11 Opto-electric sensor

Claims (6)

An objective lens at a measurement point set on the two target planes, with a pixel plane and a matte plane in a single-lens reflex digital camera as target planes, a chart pattern image emitted from a reference point, and the optical path of the pattern image switched by a shutter mirror of the camera When the image is formed through, the objective lens is moved back and forth to detect the reflected image from the measurement point photo-electrically at the conjugate point of the reference point, and the detection value when the contrast of the reflected image is the strongest is obtained. An actual mounting position between the pixel surface and the mat surface is measured based on the method, and the mounting position between the pixel surface and the mat surface in the single-lens reflex digital camera is measured.   The measuring method according to claim 1, wherein the accuracy of the mounting position of the pixel surface and the mat surface is determined based on a difference between an actual mounting position of the pixel surface and the mat surface and a reference mounting position thereof.   3. The measuring method according to claim 1, wherein when the chart pattern image is formed on the pixel surface, the shutter mirror of the camera is placed at a raised position, and when the image is formed on the mat surface, the shutter mirror is lowered. Of measuring the mounting position of the pixel surface and mat surface in a single-lens reflex digital camera.   The position of the shutter mirror is determined by arranging a sensor such as a light receiving / emitting type on the reflecting surface of the mirror, and determining whether or not a reflected image from the mirror is presented to the sensor. The measuring method of the attachment position of the pixel surface and mat surface in the single-lens reflex digital camera of any one of 1-3.   Imaging data detected when the shutter mirror is raised is data based on imaging on the pixel surface, and imaging data detected when the mirror is lowered is data based on imaging on the mat surface. A method for measuring a mounting position of a pixel surface and a mat surface in a single-lens reflex digital camera according to claim 4.   A collimator lens, a chart pattern including a light source behind the collimator lens, an objective lens disposed on the parallel light output side of the collimator lens, and a pixel of a single-lens reflex digital camera set for measurement An objective lens for forming the pattern image on the surface and the mat surface, a mirror position sensor for detecting positions above and below the set shutter mirror of the camera, and a reflected image reflected from the pixel surface and the mat surface And an optical-electrical detector arranged at a conjugate point of the collimator lens on the deflection optical path, and a shutter mirror of the set camera. Obtained by opto-electrical conversion from the respective reflected images of the pixel surface and mat surface when moved up and down. Measuring device mounting location of the pixel surface and the mat surface in the single-lens reflex digital camera, characterized in that a position data processing means for processing the electrical signals of the location data.

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