JPH0628453B2 - Position measurement method for solid-state image sensor - Google Patents

Description

The present invention relates to a charge coupled device (CCD) used as an image sensor in a solid-state imaging device.
The present invention relates to a position measuring method for a solid-state image sensor, which is applied when performing so-called registration adjustment or the like in which the solid-state image sensor is arranged at a predetermined position of the image pickup optical system such as e).

[Outline of Invention]

The present invention has a repeating pitch that has a predetermined relationship with the pixel pitch of the solid-state imaging device when performing so-called registration adjustment or the like in which the solid-state imaging device used in the solid-state imaging device is arranged at a predetermined position of the imaging optical system. By detecting the beat component due to the difference between the picture element pitch and the repetition pitch in the imaging output signal obtained by imaging the repetitive pattern with the solid-state imaging device, the position of the solid-state imaging device can be accurately adjusted by a simple operation. It is designed so that the deviation can be measured.

[Conventional technology]

Generally, in a color imaging device, imaging light is decomposed into a plurality of color components by a color separation system, and a subject image of each color component is captured by a solid-state image sensor such as a CCD or an imaging tube, and each imaging output is obtained. To form and output a standard color television signal of NTSC system or the like. In a color image pickup apparatus using a plurality of image sensors, it is necessary to surely maintain a state in which subject images of respective color components picked up by the image sensors are superposed, that is, a so-called registration adjustment is accurately performed.

In a conventional so-called three-tube color video camera, a three-color separation prism of a color separation system and three image pickup tubes are mechanically attached to a housing formed by die casting or the like, and an output signal obtained by photographing a test chart or the like is used. The registration of each image pickup tube is adjusted by mechanically adjusting the position and further finely adjusting the image pickup screen position using the deflection system of the image pickup tube.

For such a three-tube color video camera, CC
In a solid-state color image pickup device that uses a solid-state image pickup device such as D as an image sensor, it is not possible to electrically adjust the image pickup screen position like an image pickup tube. Therefore, in each solid-state image sensor that picks up a subject image of each color component, A holder made of iron or the like is joined, and a holder is also joined to each light emitting part of the color separation prism of the color separation system.
For each image sensor, as shown by the arrows in Fig. 4, (1) Horizontal center (arrow ± X direction) adjustment (2) Vertical center (arrow ± Y direction) adjustment ( 3) Back focus (arrow ± Z direction) adjustment (4) Horizontal tilt (arrow ± RX direction) adjustment (5) Vertical tilt (arrow ± RY direction) adjustment (6) Rotation (arrow ± RZ direction) adjustment After adjusting the registration in the 6-axis directions, the holders are heat-welded by soldering or the like to attach and fix the solid-state image sensors to the emission surfaces of the color separation prism.

[Problems to be solved by the invention]

In general, a solid-state image sensor such as a CCD cannot adjust the image pickup screen position electrically like a pickup tube. Therefore, in a color image pickup apparatus using a plurality of solid-state image sensors, the registration of each image sensor is mechanically performed. Must be maintained at extremely high accuracy. Particularly, in the solid-state color image pickup device which adopts the so-called spatial pixel shift method to achieve high resolution, the above-mentioned ± X direction, arrow ± Y direction, ± Z direction, ± RX, ± RY direction and ± RZ It is necessary to secure a registration on the order of 1 μm in the six axial directions, and conventionally, it took a lot of time and effort to adjust the registration.

Therefore, the present invention provides a method for measuring the position of a solid-state imaging device, which enables the registration adjustment to be performed with high accuracy by a simple operation.

[Means for solving problems]

In order to solve the above-mentioned problems, a method for measuring the position of a solid-state image sensor according to the present invention, in measuring the relative position shift of a plurality of solid-state image sensors that capture the same image, the horizontal or vertical direction Of at least one direction of the solid-state image pickup device, the solid-state image pickup device picks up an image of a repeating pattern in which light and shade are repeated at a repeating pitch having a predetermined relationship with the pixel pitch of the solid-state image pickup device, and is included in the image pickup output signal obtained from each solid-state image pickup device. The beat component based on the difference between the picture element pitch and the repeating pitch is detected, and the beat component detected from the reference solid-state image sensor and the beat component detected from the measured solid-state image sensor measuring the positional deviation By detecting the phase difference, the positional deviation of the measured solid-state image sensor with respect to the reference solid-state image sensor in the direction of the repeating pattern is detected as the phase difference. Characterized in that as measured by.

[Action]

In the position measuring method for a solid-state image sensor according to the present invention, a repetitive pattern having a repeating pitch having a predetermined relationship with a pixel pitch of the solid-state image sensor in at least one direction in the horizontal or vertical direction is imaged by the solid-state image sensor. The obtained imaging output signal includes a beat component based on the difference between the picture element pitch and the repetition pitch. Then, as the phase difference between the beat component included in the image pickup output signal of the reference solid-state image pickup device and the beat component included in the image pickup output signal of the measured solid-state image pickup device for measuring the positional deviation, the solid-state image pickup used as the reference is obtained. The positional deviation of the measured solid-state imaging device with respect to the device in the direction of the repeating pattern is measured.

〔Example〕

An embodiment of a position measuring method for a solid-state image sensor according to the present invention will be described in detail below with reference to the drawings.

The embodiment shown in FIGS. 1 to 3 is one in which the present invention is applied to a registration adjusting device for adjusting the registration of a three-plate CCD color video camera.

The registration adjusting device in this embodiment has a registration measuring test chart 10 having a predetermined test pattern formed on the front surface of a master lens 20, as schematically shown in FIG. And the above registration measurement test chart 10
The imaging light of the test pattern by the above-mentioned master lens 2
0 to a color separation prism 30 of a three-plate CCD color video camera, and the color separation prism 30 converts the above-mentioned imaging light into three primary color lights R, G, B, that is, red component light R, green component light G, blue component. 3 CCs split into light B
The D image sensors 31r, 31g, 31b are irradiated. Each CCD image sensor 31r,
31g and 31b are attached to position adjusting jigs 40r, 40g, and 40b that perform six-dimensional alignment, respectively. Then, each of the CCD image sensors 31r, 3
1g and 31b are driven by a CCD drive circuit 51 that operates based on a reference signal provided by a reference signal generator 50, and an image, that is, a test pattern by the imaging light of each color component dispersed by the color separation prism 30 is displayed. Take an image. Each CCD image sensor 31r, 31g, 31
The image pickup outputs obtained in b are respectively the preamplifier 41.
From r, 41g, 41b, gate circuits 42r, 42g,
It is supplied to the matrix circuit 43 via 42b. Here, each of the gate circuits 42r, 42g, 42b has a gate pulse generation circuit 5 which operates based on the reference signal.
The gate pulse generated by 2 is supplied.

The image output signal obtained by the matrix circuit 43 is
The high-resolution monitor 46 is supplied to the oscilloscope 44 for observing waves and also through the video signal processing circuit 45.
It is supplied to the microcomputer 48 via the digitizer 47.

Master lens 20 of the registration adjusting device
The registration measuring test chart 10 arranged on the front surface of the CCD is, as schematically shown in FIG.
Pitch of the image sensor 31 is twice the pitch 2c, which is twice the pixel pitch τc, and τp = 2τc ± Δ is a repeating pattern in which light and shade are repeated at a repeating pitch τp in the relationship of the first expression. The PT image is applied to the CCD image sensor 31.

Here, Δ is the value of the CCD image sensor 31 so that the image pickup output by the CCD image sensor 31 includes n beat components in one horizontal scanning period (1H) as shown in FIG. 4, for example. It is set to Δ = nτcτp / τo (n is an arbitrary number of 1 or more), where τo is the effective image size in the pixel array direction.

Registration measurement test chart 1 as described above
The image pickup output obtained by the CCD image sensor 31 irradiated with the image pickup light of the test pattern by 0 is the repeating pitch τp of the repeating pattern PT and each pixel pitch τ.
A moiré pattern is generated based on the difference from c, and the signal level changes as shown in FIG. 1 according to the relative position of the repeating pattern PT and each picture element S, and as shown in FIG. In the period (1H), n beat components are included.

The amplitude of the beat component included in the imaging output signal obtained by imaging the repetitive pattern of the registration measuring test chart 10 by the CCD image sensor 31 has the amplitude of the back focus of the imaging optical system and the amount of tilt of the solid-state imaging device. That is, it changes depending on the above-mentioned registration error in the ± Z direction and ± RX direction, and its phase also changes depending on the above-mentioned registration error in the ± X direction.

Therefore, the CCD image sensors 31r, 31g,
Regarding each imaging output obtained by 31b, while observing the waveform of each beat component shown in FIG. 3 by the oscilloscope 44, each of the position adjusting jigs 40r, 40g, 40b
Each CCD image sensor 31r, 31g, 31b
By adjusting the back focus adjustment and horizontal tilt adjustment by moving the to maximize the amplitude of each beat component, and by aligning the phases of the above beat components, the center of the horizontal direction is adjusted. Adjustment can be performed, and the registration adjustment of the CCD image sensors 31r, 31g, 31b can be performed with high accuracy by a simple operation.

In the above-described embodiment, the case where the registration adjustment in the horizontal direction is performed by the repetitive pattern having the relation of the first formula with respect to the horizontal picture element pitch of the CCD image sensor 31 has been described. The registration adjustment in the vertical direction can be performed by capturing an image of the repetitive pattern having the relationship of the first expression with respect to the vertical pixel pitch of.

〔The invention's effect〕

As is apparent from the above description of the embodiments, in the position measuring method of the solid-state image pickup device according to the present invention, in measuring the relative positional deviation of the plurality of solid-state image pickup devices that capture the same image, the horizontal or vertical direction is measured. Of at least one direction of the solid-state image pickup device, the solid-state image pickup device picks up an image of a repeating pattern in which light and shade are repeated at a repeating pitch having a predetermined relationship with the pixel pitch of the solid-state image pickup device, and is included in the image pickup output signal obtained from each solid-state image pickup device. The beat component based on the difference between the picture element pitch and the repeating pitch is detected, and the beat component detected from the reference solid-state image sensor and the beat component detected from the measured solid-state image sensor measuring the positional deviation By detecting the phase difference, the positional deviation of the measured solid-state image sensor with respect to the reference solid-state image sensor in the direction of the repeating pattern is detected. It can be measured with high precision by a simple operation as retardation.

Therefore, by applying the present invention, it is possible to provide a color video camera capable of performing color image pickup with good image quality by performing registration adjustment with extremely high accuracy and workability for each solid-state image pickup element. The purpose of the period can be fully achieved.

[Brief description of drawings]

1 to 3 are drawings showing an embodiment of a registration adjusting apparatus to which the method of the present invention is applied.
FIG. 2 is a schematic diagram for explaining the operation principle of the position measurement of the solid-state image sensor according to the method of the present invention, and FIG. 2 is a block diagram showing the configuration of the registration adjusting device.
FIG. 3 is a waveform diagram for explaining the operation of adjusting the registration of each CCD image sensor in the horizontal direction in the above embodiment. FIG. 4 is an external perspective view of a CCD image sensor for explaining the adjustment operation direction in general registration adjustment. 10 ... Test chart 20 ... Master lens 30 ... Color separation prism 31r, 31g, 31b ... CCD image sensor

Claims (1)

[Claims] 1. When measuring a relative positional deviation of a plurality of solid-state image pickup devices for picking up the same image, a repetition having a predetermined relationship with a pixel pitch of the solid-state image pickup device in at least one of horizontal and vertical directions. Each solid-state image sensor captures an image of a repeating pattern that repeats light and shade at pitches, and detects the beat component based on the difference between the picture element pitch and the repeat pitch included in the imaging output signal obtained from each solid-state image sensor. Beat component detected from the solid-state image sensor that becomes
By detecting the phase difference with the beat component detected from the solid-state image sensor to be measured for measuring the positional shift, the positional shift in the repeating pattern direction of the solid-state image sensor to be measured with respect to the reference solid-state image sensor is determined as described above. A method for measuring the position of a solid-state image sensor, characterized in that it is measured as a phase difference.