JP2009152879A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of surely obtaining an image with high resolution. <P>SOLUTION: The imaging apparatus includes: an image pickup device 1; an optical element arranged on the front surface on the incident side of light of the image pickup device; a shift means 22 for driving the optical element to shift a light axis of the light of an object made incident on the image pickup device by a predetermined amount; a storage means 23 for storing a plurality of images shifted by the shift means and shifted by each shift amount acquired by the image pickup device; a determination means 24 for determining whether or not shift amounts of the n-th image and the (n-1)-th image of the images stored in the storage means are the predetermined amount; a control means 27 for controlling whether to re-acquire the images of each shift amount or to use the images of each shift amount based on a determination result of the determination means; and an image synthesizing means 25 for forming a synthetic image using the images stored in the storage means when it is determined that the shift amount is the predetermined amount by the determination means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an imaging apparatus that acquires a pixel shift image.

Conventionally, the relative position between the optical axis of the photographic optical system and the image sensor is changed minutely by tilting the parallel flat glass, and the number of apparent pixels is increased by acquiring images at each position to increase the resolution. Has been proposed (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 7-255015

  However, in the conventional imaging device, when the parallel flat glass for shifting the relative position is not inclined by a predetermined amount and the shift amount of each acquired image is not the predetermined shift amount, each shifted image is displayed as an image. There is a problem that high-resolution image acquisition fails because it is not known whether there is an abnormality in the shift amount of the acquired image until it is synthesized and displayed on the monitor and observed.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an imaging apparatus that can reliably acquire a high-resolution image.

  In order to solve the above-described problems, the present invention provides an image sensor, an optical element disposed on the front surface of the image sensor on the light incident side, and a light beam from an object that drives the optical element and enters the image sensor. Shift means for shifting the axis by a predetermined amount; storage means for storing a plurality of images shifted by the shift means and acquired by the shift amounts; and an image stored in the storage means. a determination unit that determines whether or not the shift amount between the nth image and the (n−1) th image is the predetermined amount; and whether the shift amount image is reacquired based on the determination result of the determination unit; A control unit that controls whether an image of each shift amount is used and a composite image is formed using the image stored in the storage unit when the determination unit determines that the shift amount is a predetermined amount Image synthesis means; To provide an imaging apparatus characterized by comprising.

  According to the present invention, it is possible to provide an imaging apparatus capable of reliably obtaining a high-resolution image.

  Hereinafter, an imaging apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of the imaging apparatus according to the embodiment. FIG. 2 is a block diagram illustrating the configuration of the imaging apparatus illustrated in FIG.

  In FIG. 1, the subject side imaged by the photographic optical system 101 is referred to as the front of the imaging device 100. The housing 7 of the imaging device 100 is fixed to the housing 3 with screws (not shown), and a circuit board 2 is provided that is screwed to the housing 7 with screws 12 in the inner direction of the imaging device 100. An image sensor 1 is mounted. In addition, an image sensor driving circuit 20 (see FIG. 2) for driving the image sensor 1 is mounted on the circuit board 2.

  Further, an optical window for introducing light L into the image sensor 1 is opened in front of the housing 3, and an optical filter 4 is attached to the opening, and a lens mount 6 is attached to the housing 3 by screws (not shown) in front of the optical filter 4. It is fixed. The optical filter 4 is an infrared cut filter, and cuts light having a long wavelength exceeding a predetermined wavelength.

  The imaging element 1 and the optical filter 4 have a glass holder 8 and a gear with a step cam as a displacement mechanism for tilting and moving the parallel flat glass 5 and the parallel flat glass 5 which are optical elements constituting the pixel shifting device. 9, a plain bearing 10 and a geared motor 11 which is a displacement mechanism drive unit 22 (see FIG. 2) are arranged. The gear 9 with the step cam is sandwiched between the slide bearing 10 a and the slide bearing 10 b and is fixed to the housing 3 together with the slide bearing 10 in a rotatable form.

  Further, the gear 9 with the step cam is driven to rotate by combining the geared motor 11 with the outer gear portion.

  The glass holder 8 is held in contact with the step cam portion of the gear 9 with the step cam while being bonded and fixed to the parallel flat glass 5, and moves to a posture corresponding to the step position by the rotation of the gear 9 with the step cam. As a result, the parallel flat glass 5 can be tilted and moved in the yawing and pitching directions with respect to the light L, and an image captured by the image sensor 1 is horizontal (X-axis direction) and Pixel shifting can be performed in a two-dimensional direction in the vertical direction (Y-axis direction).

  In FIG. 2, the image sensor 1 is driven by an image sensor drive circuit 20 that controls charge accumulation and readout scanning via a circuit board 2, and time-division image data is output through a signal processing unit 21. The This image is stored in the image buffer memory unit 23.

  The imaging apparatus 100 controls a two-dimensional pixel shift operation with a predetermined pixel shift amount in the horizontal direction (X-axis direction) and the vertical direction (Y-axis direction) for an image captured by the imaging element 1 by the imaging optical system 101. It is driven by the displacement mechanism drive unit 22. The displacement mechanism driving unit 22 performs the pixel shifting operation and the imaging operation alternately by the control device 27 in synchronism with the imaging device driving circuit 20.

  Pixel shift images are sequentially stored in the image buffer memory unit 23, and the images are sequentially transferred to the pixel shift amount determination unit 24. The image is further transferred to the image composition unit 25, and the image composition operation is started. At this time, if the pixel displacement amount determination unit 24 determines that the pixel displacement amount is a predetermined pixel displacement amount and is appropriate, a predetermined number of images are obtained. The image composition operation using the pixel-shifted image is performed as it is.

  On the other hand, when the pixel shift amount determination unit 24 determines that the pixel shift amount is inappropriate with respect to the predetermined pixel shift amount, the image shift operation is not performed, and feedback to that effect is performed to the control device 27. In response to this result, the control device 27 issues a re-shooting command to the image sensor drive circuit 20 and the displacement mechanism drive unit 22 and stops transferring the pixel-shifted image to the image composition unit 25.

  The pixel shift amount determination unit 24 calculates a difference between the nth pixel shifted image and the (n−1) th pixel shifted image, and determines whether the difference falls within a predetermined pixel shift amount and an allowable error range. The operation of the pixel shift amount determination unit 24 will be described later.

  In the image composition unit 25, a predetermined number of pixel shifted images having a predetermined pixel shift amount are combined, and the combined image is displayed on the display monitor 26 and observed by an observer.

  In FIG. 2, the signal processing unit 21, the image buffer memory unit 23, the pixel shift amount determination unit 24, the control device 27, and the image synthesis unit 25 may be mounted on the circuit board 2, or the signal processing unit 21, The image buffer memory unit 23, the pixel shift amount determination unit 24, the control device 27, and the image composition unit 25 may be configured as a device different from the imaging device 100.

  Next, the operation of the pixel shift amount determination unit 24 will be described in detail with reference to FIG.

  FIG. 3 is a control flowchart of the pixel shift amount determination unit 24. The image composition unit 25 captures the n-th image among the pixel-shifted images to be image composition and transfers them from the image buffer memory unit 23 to the pixel displacement amount determination unit 24 (step S1).

  It is determined whether there are two or more images transferred to the pixel shift amount determination unit 24 (step S2).

  The pixel shift determination unit 24 positions the pixel positions of the two images so as to cancel the pixel shift amount (predetermined value) with respect to the (n−1) th image transferred from the image buffer memory 23. Then, the difference between the luminance values for each pixel is obtained (step S3).

  In the pixel calculated in step S3, it is determined that the luminance value difference is appropriate if it is equal to or smaller than the threshold value, and inappropriate if it is equal to or larger than the threshold value (step S4).

  After determining that the threshold value of the difference is appropriate, it is determined whether or not a predetermined number of pixel-shifted images have been acquired. If the predetermined number has not been reached, the process jumps to step S1 and has reached the predetermined number Jumps to step S7 (step S6).

  If it is determined in step S6 that the pixel-shifted image has reached the predetermined number of images, the image composition unit 25 performs an image composition operation (step S7).

  If it is determined in step S4 that even one pixel-shifted image is inappropriate, the image synthesizing operation is not performed, and the control device 27 generates a re-shooting command (step 5).

  Through the above steps, a composite image can be acquired from the pixel shifted image in which the pixel shift amount is shifted by a predetermined amount. If there is a pixel-shifted image in which even one pixel shift amount is deviated from the predetermined amount, re-photographing is performed and a predetermined pixel-shifted image is acquired. As a result, it is possible to acquire a composite image using a pixel shifted image with no shift in the pixel shift amount.

  Note that the image used in the pixel shift amount determination unit 24 may be configured to calculate the entire difference of the original image, or may be configured to calculate a partial difference of the original image. It doesn't matter. Which one is used depends on the balance between the processing time and the determination accuracy.

  As described above, according to the imaging apparatus according to the present embodiment, it is possible to determine whether or not the shift amount of the acquired pixel-shifted image is appropriate before or after image synthesis, and based on an image with an inappropriate shift amount. Image composition can be prevented and a high-resolution image can be synthesized and acquired.

  In addition, since it is possible to determine whether or not the shift amount for acquiring the pixel shifted image is appropriate during the acquisition of the pixel shifted image, re-acquisition can be executed immediately when it is inappropriate, so the timing of image acquisition is lost. Can be prevented.

  The above-described embodiment is merely an example, and is not limited to the above-described configuration and shape, and can be appropriately modified and changed within the scope of the present invention.

1 is a cross-sectional view of an imaging apparatus according to an embodiment. FIG. 2 is a configuration block diagram of the imaging apparatus in FIG. 1. 4 is a control flowchart of a pixel shift amount determination unit 24.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image pick-up element 2 Circuit board 3 Case 4 Optical filter 5 Parallel plate glass 6 Lens mount 7 Case 8 Glass holder 9 Gear with step cam 10 Slide bearing 11 Motor with gear 12 Screw 20 Image pick-up element drive circuit 21 Signal processing circuit 22 Displacement Mechanism drive unit 23 Image buffer memory 24 Pixel shift amount determination unit 25 Image composition unit 26 Display monitor 27 Control device 100 Imaging device 101 Imaging optical system

Claims (4)

An image sensor;
An optical element disposed on the light incident side front surface of the imaging element;
Shift means for driving the optical element to shift the optical axis of light from an object incident on the imaging element by a predetermined amount;
Storage means for storing a plurality of images shifted by the shift means and shifted by respective shift amounts acquired by the imaging device;
Determination means for determining whether or not the shift amount between the nth image and the (n−1) th image of the image stored in the storage means is the predetermined amount;
Control means for controlling whether to re-acquire the image of each shift amount or use the image of each shift amount based on the determination result of the determination means;
An image composition unit that forms a composite image using an image stored in the storage unit when the determination unit determines that the shift amount is a predetermined amount;
An imaging apparatus comprising:   The determination unit calculates a difference between luminance signals in each pixel of each image of each shift amount stored in the storage device, and determines whether or not the difference is within a threshold value. Item 2. The imaging device according to Item 1. The shift means includes a parallel plate glass disposed on the incident light side of the image sensor,
The imaging apparatus according to claim 1, further comprising a tilting unit configured to tilt the parallel flat glass with respect to the optical axis. The tilting means has a ring-shaped cam ring,
The imaging apparatus according to claim 1, further comprising a driving unit that rotates the cam ring around the optical axis.

Images