JP2015228576A - On-vehicle camera device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct a change of a lens part, which expands or shrinks with a temperature change, and a change of an imaging range produced by the varied shape of the lens part, with a simple configuration without using an adjustment movable lens etc., so as to continuously output an image in a constant range if the temperature of the lens part changes.SOLUTION: A cutout range of a photographic image corresponding to the temperature of the lens part is stored in advance. From the photographic image which is input from an imaging device, an image cutout part outputs a cutout image in which a cutout range is variably set according to the temperature of the lens part. An image enlargement part then enlarges the cutout image to the same size as the photographic image.

Description

  The present invention relates to an in-vehicle camera apparatus that corrects a change in an imaging range caused by a lens expanding or contracting due to a temperature change.

  FIG. 3 is an explanatory diagram for explaining the shape of the lens and the change of the image circle formed by the lens due to a temperature change. Among these, FIG. 3-(1) is a cross-sectional view showing the shape of the lens unit 2 and the light rays incident on and emitted from the lens unit 2, and FIG. FIG.

The lens unit 2 shown by a solid line in FIG. 3 (1) shows a shape when the temperature of the lens unit 2 is 20 ° C., for example, and the temperature of the lens unit 2 becomes 60 ° C., for example, due to an increase in ambient temperature. in case of,
As the temperature rises, the lens part 2 expands and increases in thickness like the shape of the lens part 2A indicated by the dotted line.

  The light beam “X” incident on the lens unit 2 when the temperature is 20 ° C. is refracted when passing through the position indicated by “a” on the subject-side surface 21 of the lens unit 2 and passes through the inside of the lens unit 2. The lens unit 2 is refracted again when passing through the position indicated by “b” on the surface 22 on the image pickup element side and is emitted to the position indicated by “Y” on the image pickup surface of the image pickup element 3. -Form the outer periphery "Z" of the image circle shown in (2).

  Further, the light beam “X” incident on the lens unit 2A when the temperature is 60 ° C. is refracted when passing through the position indicated by “a ′” on the subject-side surface 21 of the lens unit 2A, and the inside of the lens unit 2A. , And is refracted again when passing through “b ′” on the surface 22 on the image sensor side of the lens portion 2A, and is emitted to the position indicated by “Y ′” on the image surface of the image sensor 3, and is projected onto the image surface. The outer periphery “ZA” of the image circle shown in FIG.

  Although not shown, when the temperature of the lens unit 2 is −20 ° C., the lens unit 2 contracts, and the outer periphery “of the image circle formed at the position indicated by“ Y ”on the imaging surface of the imaging device 3”. The outer circumference “ZB” of the image circle shown in FIG. 3B is formed closer to the center of the image sensor 3 than Z ”.

  As indicated by the outer peripheries “Z”, “ZA”, and “ZB” of these image circles, the size of the image circle of the lens unit 2 changes due to expansion or contraction of the lens unit 2 due to a temperature change. Along with this, the imaging range also changes.

  On the other hand, a technique corresponding to such a lens shape change due to a temperature change has been proposed (see, for example, Patent Document 1).

JP 2013-3336 A (pages 4-6, FIG. 1)

  According to the technique of Patent Document 1, it is possible to keep the size of the image circle constant even if the lens expands or contracts due to a temperature change. However, the zoom lens device disclosed in Patent Document 1 requires a temperature correction lens and a temperature correction lens driving mechanism that moves the lens to a position on the optical axis corresponding to the temperature detected by the temperature sensor. However, there is a problem that it is difficult to provide such a drive mechanism in a vehicle-mounted camera device that is particularly required to be downsized.

  An object of the present invention is to solve the above-described problems and to provide an in-vehicle camera device that can correct a change in an imaging range even if a lens temperature changes with a simple configuration.

  In order to solve the above-mentioned problems, the present invention according to claim 1 of the present invention is an in-vehicle camera device that is attached to a vehicle and captures and outputs a subject image around the vehicle. A lens unit that forms an image of the subject, an image sensor that captures the subject image formed by the lens unit and outputs the image as a captured image, a temperature sensor that detects the temperature of the lens unit, and a switch from the captured image. A storage unit that stores an image cut-out range for cutting out the output image in correspondence with the temperature of the lens unit, and the captured image based on the temperature detected by the temperature sensor and the image cut-out range stored in the storage unit An image cutout unit that cuts out and outputs the cutout image, and an image enlargement unit that outputs an enlarged image obtained by enlarging the cutout image output from the image cutout unit to the same size as the captured image; Above Characterized in that it comprises an image output section for converting the magnified image output from the image expansion section to the output signal.

  The invention according to claim 2 of the present invention is characterized in that the image cut-out range is set to be wide when the temperature of the lens portion is high and narrow when the temperature is low.

  According to the in-vehicle camera device of the present invention, an image within a certain range can always be obtained even if the temperature of the lens changes, so that the accuracy in the case of recognizing the position of the subject particularly for image recognition is improved.

It is a block diagram which shows the structure of the vehicle-mounted camera apparatus by this invention. It is explanatory drawing explaining the process of the image of the vehicle-mounted camera apparatus by this invention. It is explanatory drawing which shows the change of the shape of a lens and an image circle by a temperature change.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail as examples based on the accompanying drawings. Note that the present invention is not limited to the following embodiments, and various modifications can be made without departing from the spirit of the present invention.

  FIG. 1 is a block diagram showing a configuration of an in-vehicle camera device according to the present invention. In FIG. 1, an in-vehicle camera device 1 includes a lens unit 2 that forms a subject image around the vehicle, an image sensor 3 that captures a subject image formed by the lens unit 2, and a temperature at which the temperature of the lens unit 2 is detected. The temperature sensor 5 detects the sensor 5, a storage unit 6 that stores in advance an image cutout range in which the subject image captured by the imaging device 3 is captured in correspondence with the temperature of the lens unit 2, and the subject image captured by the imaging device 3. An image cutout unit 4 that cuts out an image cutout range corresponding to the selected temperature, and an image enlargement that enlarges the cutout image cut out by the image cutout unit 4 into an enlarged image having the same size as the subject image captured by the image sensor 3. And an image output unit 8 that converts the enlarged image enlarged by the image enlargement unit 7 into an output signal and outputs the output signal.

  The temperature sensor 5 is provided in the in-vehicle camera device 1 in the vicinity of the lens unit 2 so that the temperature of the lens unit 2 can be detected.

  Further, the image cutout range stored in the storage unit 6 is obtained by the image cutout unit 4 to be described later in order to obtain a constant range of picked up images even when the image pickup range of the lens unit 2 changes due to temperature change. The range of the cut-out image cut out from the two captured images is tabulated, and is determined in advance in association with the temperature of the lens unit 2 through experiments or the like.

  FIG. 2 is an explanatory diagram illustrating image processing of the in-vehicle camera device according to the present invention. 2- (1) to (3) are taken images output from the image sensor 3 when the lens unit 2 is at a low temperature (for example, −20 ° C.), an intermediate temperature (for example, 20 ° C.), and a high temperature (for example, 60 ° C.). 1 to 3 are indicated by solid-line frames, and rhombuses, triangles, circles, and heart shapes are captured images of a subject around the vehicle imaged on the image sensor 3 by the lens unit 2.

  Since the imaging device 3 captures and outputs the subject image formed by the lens unit 2, the lens unit 2 contracts at a low temperature in FIG. 2- (1) than at a middle temperature in FIG. 2- (2). Since the size of the image circle is reduced, the captured image 1 in a wider range than that at the middle temperature is output as a result. In addition, when the temperature in FIG. 2- (3) is high, the lens unit 2 expands and the size of the image circle becomes larger than that in the middle temperature in FIG. 2- (2). The captured image 3 is output.

  2- (4) to (6) show the cut-out images of the subject output from the image cut-out unit 4 at low temperature, medium temperature, and high temperature, respectively. The image cutout unit 4 refers to the image cutout range table in the storage unit 6 according to the temperature detected by the temperature sensor 5, and starts from the captured image 1 indicated by a solid line frame at a low temperature in FIG. A dotted frame “A” set in the image cutout range table is cut out as a cutout range, and a cutout image shown in FIG.

  Similarly, the image cutout unit 4 cuts out a dotted frame “B” set wider in the image cutout range table than at low temperature in the image cutout range table at the middle temperature in FIG. The cut image shown in (5) is output, and when the temperature is high in FIG. 2 (3), the dotted frame “C” set wider than the medium temperature in the image cut range table is cut out as the cut range. The clipped image shown in FIG. 2- (6) is output.

  The image cutout unit 4 changes the image cutout range according to the temperature change and outputs a cutout image like the image of the subject shown in FIGS. Changes in the imaging range due to expansion or contraction can be corrected.

  2 (4) to (6) output by the image cutout unit 4 are the captured images output from the image sensor 3 by the image enlargement unit 7 (FIGS. 2- (1) to (3). ) Are enlarged to the same size as the solid line frame) shown in FIG.

  And the enlarged image of FIG. 2- (7) which the image expansion part 7 output is converted into an output signal by the image output part 8, and is output from the vehicle-mounted camera apparatus 1. FIG.

  In this way, the subject image output from the in-vehicle camera device 1 is an image that always represents a certain range and position even when the temperature of the lens unit 2 changes. For example, the accuracy of recognizing the position of the object by the image recognition device Can be improved.

DESCRIPTION OF SYMBOLS 1 Car-mounted camera apparatus 2 Lens part 21 Subject side surface 22 Image sensor side surface 3 Image sensor 4 Image extraction part 5 Temperature sensor 6 Storage part 7 Image expansion part 8 Image output part

Claims (2)

  An in-vehicle camera device that is attached to a vehicle and captures and outputs a subject image around the vehicle, the lens unit that forms an image of the subject around the vehicle, and the subject image formed by the lens unit An image sensor that outputs a captured image; a temperature sensor that detects a temperature of the lens unit; and a storage unit that stores an image cutout range in which a cutout image is cut out from the captured image in correspondence with the temperature of the lens unit. Output from the image cutout unit and the image cutout unit that cut out and output the cutout image from the captured image based on the temperature detected by the temperature sensor and the image cutout range stored in the storage unit. An image enlargement unit that outputs an enlarged image obtained by enlarging the clipped image to the same size as the captured image, and an image output that converts the enlarged image output from the image enlargement unit into an output signal and outputs the output signal Vehicle camera system, characterized in that it comprises and. The in-vehicle camera device according to claim 1, wherein the image cutout range is set to be wide when the temperature of the lens unit is high and narrow when the temperature is low.

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