Source: https://patents.justia.com/patent/5805218
Timestamp: 2019-05-22 12:37:22
Document Index: 704095282

Matched Legal Cases: ['art 10', 'art 10', 'art 10', 'art 24', 'art 24', 'art 24']

US Patent for Method for adjusting a position of a solid-state image detector in a given image-forming optical system Patent (Patent # 5,805,218 issued September 8, 1998) - Justia Patents Search
Justia Patents By Detecting ContrastUS Patent for Method for adjusting a position of a solid-state image detector in a given image-forming optical system Patent (Patent # 5,805,218)
Mar 13, 1996 - Matsushita Electric Industrial Co., Ltd.
A three-dimensional resolution chart is used to adjust the position of a solid-state image detector 4 in a given image-forming optical system. A plurality of blocks 10a are provided on an upper surface of a resolution chart 10. Each block 10a has an adjusting pattern A-D depicted on a slant surface thereof. An image of each adjusting pattern A-D is formed-on the solid-state image detector 4 through a master lens 2. The contrast integration value F is calculated based on the image of the adjusting pattern at each of a plurality of designated areas hj (j=1 - - - n) on the slant surface of each block 10a provided on the resolution chart 10, to find out a specific position on each block where the contrast integration value F becomes maximum, thereby identifying the specific position as focus point of the master lens 2. The back focus of the solid-state image detector 4 is calculated based on thus obtained focus point. An optimum gradient (.alpha., .beta.) of the solid-state image detector 4 is calculated based on three-dimensional relationship between plural focus points of the master lens 2 detected on the plural blocks 10a. Finally, each positioning mechanism 11 adjusts each solid-state image detector 4 to the calculated optimum position or at the optimum gradient.
FIG. 24 is a view illustrating an .alpha. axis adjustment in accordance with the eighth embodiment of the present invention;
FIG. 25 is a view illustrating the .alpha. axis adjustment in accordance with the eighth embodiment of the present invention;
FIG. 26 is a view illustrating a .beta. axis adjustment in accordance with the eighth embodiment of the present invention;
FIG. 27 is a view illustrating the .beta. axis adjustment in accordance with the eighth embodiment of the present invention;
Furthermore, another characteristic feature of the first embodiment resides in a positioning mechanism 11 which shifts each solid-state image detector 4 to the focus point of master lens 2. Each positioning mechanism 11, as shown in FIG. 1, has the capability of adjusting a corresponding solid-state image detector 4 along each of the principal six axes, i.e. horizontal direction "X", vertical direction "Y", optical axis direction "Z", rotational direction .theta. about the optical axis, gradient .alpha. with respect to the horizontal direction "X", and gradient .beta. with respect to the vertical direction "Y".
If the gradient .alpha. and the gradient .beta. of the solid-state image detector 4 are not inclined with respect to the optical axis (i.e. Z direction), the height h of the maximum contrast integration area from the reference plane will be the same value at each of four adjusting patterns A through D on the triangular blocks 10a located at four corners of resolution chart 10.
Meanwhile, if the gradient .alpha. and the gradient .beta. are inclined with respect to the optical axis "Z", the height h of the maximum contrast integration area from the reference plane will not be the same value at each of four adjusting patterns A through D, as shown in FIG. 6.
Based on thus obtained correction data, the correction drive circuit 8 controls each positioning mechanism 7 so as to change the horizontal gradient .alpha. and the vertical gradient .beta. with respect to the optical axis Z, thereby accurately adjusting the actual gradient of each solid-state image detector 4 to the optimum value.
Each adjusting pattern 23 is stripes depicted on the slant flat surface of each triangular block 21. More specifically, the adjusting pattern 23 consists of parallel alternate black and white lines 22 inclined along the slope at a predetermined angle .theta. with respect to the longitudinal direction of the slant surface, at predetermined intervals.
In FIG. 8, the inclined angle .theta. is expressed by the following equation (2).
tan .theta.=tan .phi.=(X-x) / (2Z) (2)
where .phi. represents an angle between optical axis 25 and inclined line 22, X represents a width of 3-D resolution chart 24, x represents a width of solid-state image detector 4, and Z represents a distance between resolution chart 24 and solid-state image detector 4.
FIG. 10 is a video image of 3-D resolution chart 24 to be displayed on the TV monitor 6 in accordance with the second embodiment of the present invention, wherein the image of stripes can be obtained as correct alternate black-and-white lines extending straight with respect to the screen of TV monitor 6, as an effect of inclined layout of stripes by the angle .theta..
When the .alpha.-axis gradient of a concerned solid-state image detector is large, the focus point of the master lens may be largely deviated from the .alpha.-axis adjusting triangular block 112. In such a case, the focus point of the master lens appears on the image plane 131 shown in FIG. 24. If the focus point of the master lens is focused at the center of focus-point-measuring area 121, the focus point of the master lens may be offset out of the surface of .alpha.-axis adjusting triangular block 133 as shown in FIG. 24. However, it will be possible to detect the focus point of the master lens on the surface of .alpha.-axis rough gradient adjusting area 122, since the .alpha.-axis rough gradient adjusting area 122 is stepped down in parallel with the surface of the focus-point-measuring area 121 as shown in FIG. 23.
Thus, as shown in FIG. 25, referring to two focus points of the master lens detected on the gradient rough adjusting triangular block 141, the .alpha.-axis gradient of the solid-state image detector is adjusted in such a manner these two focus points detected on two stepped slopes are equalized in the height from the optical axis.
Accordingly, in FIG. 24, the distance from the focus point of the master lens focused in the vicinity of the center of focus-point-measuring area 134 to the reference plane can be equalized to the distance from the focus point of the master lens detected on the .alpha.-axis rough adjusting area 134, roughly positioning the pixel face of the solid-state image detector in parallel with the reference plane of the resolution chart.
After finishing the rough adjustment of .alpha.-axis gradient, it is recommendable to perform a fine adjustment using the focus points formed on the surfaces of .beta.-axis adjusting block 112 and the block 111.
The adjustment of .beta.-axis gradient is performed in the same manner as .alpha.-axis gradient adjustment.
When the .beta.-axis gradient of a concerned solid-state image detector is large, the focus point of the master lens may be offset out of the surface of the .beta.-axis adjusting triangular block 113 shown in FIG. 22. In such a case, the focus point of the master lens will appear on the image plane 151 as shown in FIG. 26. If the focus point of the master lens is focused at the center of focus-point-measuring area 121, the focus point of the master lens may be offset out of the surface of .beta.-axis adjusting triangular block 153 as shown in FIG. 26. However, it will be possible to detect the focus point of the master lens on the surface of .beta.-axis rough gradient adjusting area 123, since the .beta.-axis rough gradient adjusting area 123 is provided inward but on the same plane as the surface of the focus-point-measuring area 121 as shown in FIG. 23.
Thus, as shown in FIG. 27, referring to two focus points of the master lens detected on the gradient rough adjusting triangular block 161, the .beta.-axis gradient of the solid-state image detector is adjusted in such a manner that these two focus points are equalized in their positions with respect to the Y axis of the frame memory in the image processing device.
Accordingly, in FIG. 26, the distance from the focus point of the master lens focused in the vicinity of the center of focus-point-measuring area 154 to the reference plane can be equalized to the distance from the focus point of the master lens detected on the .beta.-axis rough adjusting area 155, roughly positioning the pixel face of the solid-state image detector in parallel with the reference plane of the resolution chart.
After finishing the rough adjustment of .beta.-axis gradient, it is recommendable to perform a fine adjustment using the focus points formed on the surfaces of .beta.-axis adjusting block 113 and the block 111.
Regarding X-, Y- and .theta.-directional dislocations of the solid-state image detector can be obtained even by the conventional 2-D resolution chart, using the image signal of the resolution chart taken by the solid-state image detector.
However, the conventional 2-D resolution chart is no longer useful to detect .alpha.-, .beta.- and Z-directional dislocations (i.e. gradient and back focus) of the solid-state image detector, because the conventional adjustment based on the 2-D resolution chart can be performed only when the solid-state image detector is movable in the optical-axis direction. More specifically, this conventional adjustment basically relies on the repetitive shift adjustment of the solid-state image detector in the optical direction to find out the position of maximum contrast integration value as described previously. Thus, the conventional adjustment cannot be employed for the detection of the .alpha.-, .beta.- and Z-directional dislocations (i.e. gradient and back focus) of the stationary solid-state image detector which is already bonded by adhesive material.
Subsequently, the optimum position of the solid-state image detector, i.e. .alpha.-, .beta.- and Z-directional values, can be calculated based on the obtained focus points.
In this manner, the ninth embodiment of the present invention takes in the image of the 3-D resolution chart by the solid-state image detector through the master lens after hardening the adhesive material bonding the solid-state image detector at the optimum position in the given image-forming optical system, and calculates the gradient and the back focus of the solid-state image detector based on the obtained image data without shifting the solid-state image detector in the back-and-forth direction of the optical axis. Hence, it becomes possible to detect the positional deviations in each of .alpha., .beta. and Z directions even after the solid-state image detector is firmly fixed by adhesive material.
1. A method for adjusting the position of a solid-state image detector in a given image-forming optical system, comprising steps of:
providing a three-dimensional resolution chart comprising a block provided on an upper surface thereof, said block having an adjusting pattern depicted on a slant surface thereof;
forming an image of said adjusting pattern of said three-dimensional resolution chart on a solid-state image detector through a master lens;
calculating a contrast integration value based on the image of said adjusting pattern at each of a plurality of designated areas on said slant surface of said block provided on said resolution chart, and finding out a specific position where said contrast integration value becomes maximum, thereby identifying said specific position as focus point of said master lens;
calculating an optimum position of said solid-state image detector in the given image-forming optical system, based on said focus point; and
positioning said solid-state image detector to said optimum position by using a positioning mechanism.
2. A method for adjusting the position of a solid-state image detector in a given image-forming optical system, comprising steps of:
providing a three-dimensional resolution chart comprising a plurality of blocks provided on an upper surface thereof, each block having an adjusting pattern depicted on a slant surface thereof;
forming an image of each adjusting pattern of said three-dimensional resolution chart on a solid-state image detector through a master lens;
calculating a contrast integration value based on the image of said adjusting pattern at each of a plurality of designated areas on said slant surface of each block provided on said- resolution chart, and finding out a specific position on each block where said contrast integration value becomes maximum, thereby identifying said specific position as focus point of said master lens;
calculating an optimum gradient of said solid-state image detector in the given image-forming optical system, based on three-dimensional relationship between plural focus points of said master lens detected on said plural blocks; and
adjusting an actual gradient of said solid-state image detector to said optimum gradient by using a positioning mechanism.
3. A method for adjusting the position of a solid-state image detector in a given image-forming optical system, comprising steps of:
providing a three-dimensional resolution chart comprising a block provided on an upper surface thereof and a reference plane, said block having a first adjusting pattern depicted on a slant surface thereof and said reference plane having a second adjusting pattern depicted thereon;
forming images of said first and second adjusting patterns of said three-dimensional resolution chart on a solid-state image detector through a master lens;
calculating a contrast integration value based on the image of said first adjusting pattern at each of a plurality of designated areas on said slant surface of said block provided on said resolution chart, and finding out a specific position where said contrast integration value becomes maximum, thereby identifying said specific position as focus point of said master lens;
obtaining a center-of-gravity position of said second adjusting pattern based on the image of said second adjusting pattern;
calculating an optimum position of said solid-state image detector in the given image-forming optical system, based on said focus point and said center-of-gravity position; and
4. A method for adjusting the position of a solid-state image detector in a given image-forming optical system, comprising steps of:
providing a three-dimensional resolution chart comprising a plurality of blocks provided on an upper surface thereof and a reference plane, each block having a first adjusting pattern depicted on a slant surface thereof and said reference plane having a second adjusting pattern depicted thereon so as to correspond to said first adjusting pattern;
calculating a contrast integration value based on the image of said first adjusting pattern at each of a plurality of designated areas on said slant surface of each block provided on said resolution chart, and finding out a specific position where said contrast integration value becomes maximum, thereby identifying said specific position as focus point of said master lens;
calculating an optimum gradient of said solid-state image detector in the given image-forming optical system, based on three-dimensional relationship between plural focus points of said master lens detected on said plural blocks and said center-of-gravity position corresponding to each of said focus points; and
5. A method for adjusting the position of a solid-state image detector in a given image-forming optical system, comprising steps of:
displaying a composite image by superimposing said focus point on said image of said adjusting pattern; and
positioning said solid-state image detector to a predetermined position based on said displayed composite image by using a positioning mechanism.
6. A method for adjusting the position of a solid-state image detector in a given image-forming optical system, comprising steps of:
calculating a contrast integration value based on the image of said adjusting pattern at each of a plurality of designated areas on said slant surface of each block provided on said resolution chart, and finding out a specific position where said contrast integration value becomes maximum, thereby identifying said specific position as focus point of said master lens on each of said plural blocks;
displaying a composite image by superimposing plural focus points on corresponding images of said plural adjusting patterns; and
adjusting an actual gradient of said solid-state image detector to an optimum gradient based on said composite image by using a positioning mechanism.
7. The position adjusting method defined by any one of claims 1 to 6, wherein the adjusting pattern depicted on the slant surface of said block of said three-dimensional resolution chart is capable of correcting distortion aberration of said master lens.
11. A method for adjusting the position of a solid-state image detector in a given image-forming optical system, comprising steps of:
calculating a contrast integration value based on the image of said adjusting pattern at each of a plurality of designated areas on said slant surface of each block provided on said resolution chart, and finding out a specific position on each block where said contrast integration value becomes maximum, thereby identifying said specific position as focus point of said master lens;
adjusting an actual gradient of said solid-state image detector to said optimum gradient by using a positioning mechanism, wherein
one of said plural blocks is capable of measuring a predetermined different or supplementary area in addition to an ordinary measuring area common to other blocks, thereby allowing a wide range of measurement of the focus point of the master lens.
5444481 August 22, 1995 Ohshima et al.
Inventors: Kouji Ohura (Yokohama), Keiji Shintani (Tokyo), Yoko Koseki (Yokosuka), Hiroto Toba (Yokohama), Toshiro Obi (Yokohama), Kazuyuki Kobayashi (Yokohama)
Application Number: 8/614,496
Current U.S. Class: By Detecting Contrast (348/353); Using Test Chart (348/188)