阅读说明：本技术 低成本摄像头 (Low-cost camera ) 是由 E·J·李 D·A·布莱克 N·J·贝姆 W·L·托纳尔 于 2018-08-10 设计创作，主要内容包括：本发明提供了一种成像系统,其具有HD图像传感器、变焦透镜,其定位在图像传感器前方并且构造成响应于电刺激而改变至少一个光学特性,以便改变图像传感器的视场。所述成像系统还包括控制器,其联接到变焦透镜,并且配置成通过选择要施加到变焦透镜的电刺激来选择图像传感器的视场。(An imaging system is provided having an HD image sensor, a zoom lens positioned in front of the image sensor and configured to change at least one optical characteristic in response to an electrical stimulus so as to change a field of view of the image sensor. The imaging system also includes a controller coupled to the zoom lens and configured to select a field of view of the image sensor by selecting an electrical stimulus to be applied to the zoom lens.)

1. An imaging system for a vehicle, comprising:

a high-definition image sensor disposed in the vehicle;

a zoom lens positioned in front of the image sensor and configured to change at least one optical characteristic in response to an electrical stimulus so as to change a field of view of the image sensor; and

a controller coupled to the zoom lens and configured to select a field of view of the image sensor by selecting an electrical stimulus to be applied to the zoom lens.

2. The imaging system of claim 1, wherein the zoom lens is an electrowetting lens.

3. The imaging system of any of claims 1-2, wherein the image sensor is mounted in the vehicle so as to have a forward field of view.

4. The imaging system of claim 3, wherein the image captured by the image sensor is analyzed by the controller, and wherein the controller generates a control signal configured to control exterior lights of the vehicle.

5. The imaging system of claim 4, wherein the image sensor maintains a high pixel count per degree field of view as the field of view narrows to focus on distant objects.

6. The imaging system of claim 4, wherein the controller varies the electrical stimulus to be applied to the zoom lens to cause the field of view to move to correspond to an upcoming turn on a road on which the vehicle is traveling.

7. The imaging system of any of claims 1-6, wherein the image sensor is mounted in the vehicle so as to have a rear field of view external to the vehicle.

8. The imaging system of any of claims 1-7, wherein the image sensor is mounted in the vehicle so as to have a rear field of view of the vehicle interior.

9. The imaging system of claim 8, wherein the controller varies the electrical stimulation to be applied to the zoom lens to cause the field of view to move around the interior of the vehicle to view different locations of the vehicle interior.

10. The imaging system of any of claims 1-9, wherein the controller varies an electrical stimulus to be applied to the zoom lens to cause the field of view to move.

11. The imaging system of any of claims 1-10, wherein the controller varies an electrical stimulus to be applied to the zoom lens to cause the field of view to narrow or widen.

12. The imaging system of any of claims 1-11, wherein the electrical stimulation is applying at least one of a voltage and an electric field gradient.

13. The imaging system of any of claims 1-12, wherein images captured by the image sensor are analyzed by the controller, and wherein the controller provides the analysis for at least one of: headlight control, autonomous vehicle control, lane departure warning, lane keeping assist, adaptive cruise control, forward collision warning, rear collision warning, pedestrian detection, traffic sign recognition, object detection, parking assist, and blind spot detection.

14. The imaging system of any of claims 1-13, wherein the output from the camera is in an analog format.

15. An imaging system, comprising:

a high-definition image sensor;

an electrowetting lens positioned in front of the image sensor and configured to change at least one optical characteristic in response to an electrical stimulus so as to change a field of view of the image sensor; and

a controller coupled to the electrowetting lens and configured to select a field of view of the image sensor by selecting an electrical stimulus to be applied to the electrowetting lens.

16. The imaging system of claim 15, wherein the controller varies an electrical stimulus to be applied to the electrowetting lens to cause the field of view to move.

17. The imaging system of any of claims 15-16, wherein the controller varies an electrical stimulus to be applied to the electrowetting lens to cause the field of view to narrow or widen.

18. The imaging system of any of claims 15-17, wherein the electrical stimulation is applying at least one of a voltage and an electric field gradient.

19. The imaging system of any of claims 15-18, wherein the image sensor is located in one of: security cameras, smart phones, laptop computers, and notebook computers.

20. The imaging system of any of claims 15-19, wherein the controller selects two different electrical stimuli to alternate the field of view of the image sensor back and forth to obtain a first stream of images having a first field of view and a second stream of images having a second field of view.

21. The imaging system of any of claims 15-20, wherein the controller supplies the first image stream to a first display and the second image stream to a second display.

22. The imaging system of claim 20, wherein the controller supplies the first and second image streams to a first display for simultaneous display in different display areas of the first display.

23. The imaging system of any of claims 15-22, wherein the output from the camera is in an analog format.

Technical Field

The present invention generally relates to imaging systems (cameras) for use in vehicles.

Disclosure of Invention

According to an aspect of the present invention, there is provided an imaging system for a vehicle, the imaging system comprising: a high-definition image sensor provided in a vehicle; a zoom lens positioned in front of the image sensor and configured to change at least one optical characteristic in response to an electrical stimulus so as to change a field of view of the image sensor; and a controller coupled to the zoom lens and configured to change a field of view of the image sensor by selecting an electrical stimulus to be applied to the zoom lens.

According to another embodiment of the present invention, there is provided an imaging system including: a high-definition image sensor; an electrowetting lens located in front of the image sensor and configured to change at least one optical characteristic in response to an electrical stimulus so as to change a field of view of the image sensor; and a controller coupled to the electrowetting lens and configured to select a field of view of the image sensor by selecting an electrical stimulus to be applied to the electrowetting lens.

These and other features, advantages, and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims, and appended drawings.

Drawings

The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:

fig. 1 is a block diagram showing an imaging system according to a first embodiment;

FIG. 2A is a block diagram showing the use of an electrowetting lens to function with a narrower field of view;

FIG. 2B is a block diagram showing the use of an electrowetting lens to function with a wider field of view;

FIG. 2C is a block diagram showing the use of an electrowetting lens to function with a moving field of view;

FIG. 3A is a top view of a vehicle having multiple imaging systems constructed in accordance with the embodiment shown in FIG. 1;

FIG. 3B is a top view of the vehicle shown in FIG. 3A, with the field of view of the camera changed; and

fig. 4 is a block diagram showing an imaging system according to a second embodiment.

Detailed Description

Automotive cameras are used for a wide variety of functions in vehicles. Such uses include controlling vehicle equipment to supplement the driver's view of the vehicle's surroundings. Cameras that supplement the driver's field of view include rear-facing cameras, for example, cameras for a Reverse Camera Display (RCD) system and cameras for a Full Display Mirror (FDM) system. The cameras for the RCD system and the FDM system may be aimed in the same general direction but with different fields of view (FOV) and focal points. Thus, in a vehicle that provides both an RCD system and an FDM system, two cameras have been mounted to the rear of the vehicle, each camera providing images for a different one of the two systems.

Due to reliability requirements, the resolution of automotive cameras tends to be much lower than consumer products. For example, the latest automotive grade part is 2MP, and the recently published 7.5MP sensor will be released in 2018. The reason for the increased resolution is to cope with european 2021 NCAP requirements, where the forward facing sensor must have sufficient resolution to view the vehicle side pedestrians, and the center still has sufficient resolution. A similar problem exists in the backward direction, i.e. 170ppi is required at 50 degrees and 1600 pixels wide, which means that for a 180 ° FOV surround system with a standard fixed focus lens a 24MP sensor is required. Accordingly, digital High Definition (HD) cameras have been used to provide these higher resolutions. However, these digital HD cameras require expensive serializer/deserializer pairs and associated connectors (coaxial connectors). As used herein, an HD camera/image sensor has a signal-to-noise ratio of at least about 90 dB.

The inventors have found that by using a zoom lens, a wide FOV required for certain automotive applications can be obtained while using a camera with a lower resolution. Thus, for example, an analog HD camera may be used with a zoom lens. Analog HD cameras offer the benefit of not requiring the associated connectors of expensive serializer/deserializer pairs and their digital copies. Thus, less expensive twisted pair cables and conventional crimp and snap connector systems may be used. Suitable analog encoders are available from Techpoint Inc. (San Jose, California).

Fig. 1 shows an example of an imaging system 10 having: an HD image sensor 20; a zoom lens (e.g., an electrowetting lens 30) positioned in front of the image sensor 20 and configured to change at least one optical characteristic in response to an electrical stimulus so as to change a field of view of the image sensor 20; and a controller 40 coupled to the zoom lens 30 and configured to select a field of view of the image sensor 20 by selecting an electrical stimulus to be applied to the zoom lens 30. The zoom lens 30 may also be used for auto-focusing.

The variable focus lens 30 may take any form known in the art, including the form shown in fig. 1 and 4. In general, as shown in fig. 1, the variable focus lens 30 is an electrowetting lens that includes an oil lens 32 that can take various shapes to form a variable lens in response to application of an electrical stimulus (e.g., application of a selected voltage to one or more electrodes 34 in the electrowetting lens 30). The lens 30 may include two glass substrates 35a, 35b that combine with electrodes 34a, 34b and an insulating member 36a to form a cavity in which the oil lens 32 is disposed. The rest of the chamber in which the oil lens 32 is located is filled with another fluid, such as water 33, which does not mix with the oil lens 32. Note that the electrode 34b of the contact oil lens 32 may be coated with an insulator material. Fig. 2A, 2B and 2C show three examples of shapes that the oil lens 32 may form in response to two different voltages applied to the electrodes 34a, 34B. In fig. 2A, the oil lens 32 is in the shape of a convex glass lens, and the electrowetting lens 30 functions as a biconvex lens. In fig. 2B, the oil lens 32 is in the shape of a concave glass lens, and the electrowetting lens 30 functions as a biconcave lens. In fig. 2C, the oil lens 32 is in a tilted or rotated shape such that the electrowetting lens 30 moves the field of view to one direction (i.e., left, right, up, or down). By changing the shape of the oil lens 32, the focal length can be changed as well as the direction of the optical axis. When placed in front of the image sensor 20, the electrowetting lens 30 may be used to change the field of view of the image sensor 20 and translate the field of view across the imaging surface of the image sensor 20. This capability would provide many advantages in imaging systems used in vehicles as well as security cameras and mobile devices (e.g., smart phones, notebook computers, and laptop computers).

The electrowetting lens 30a shown in fig. 4 is similar to that shown in fig. 1, except that the configuration of the electrode 34b is different and the rear glass substrate 35b comprises a spherical recess, wherein the electrode 34b covers the entire surface of the substrate 35 b. An insulating layer 36b is provided across the entire surface of the electrode 34b and fills the electrode-covered spherical recess in the substrate 35 b. Further, an annular glass ring 35c may be provided around the periphery of the chamber between the substrates 35a and 35 b. In this lens configuration, the oil droplets are centered by the gradient in the electric field applied through the electrodes 34a, 34b to form the oil lens 32.

One example of an application for the imaging system 10 would be a rear-view camera 10a of a vehicle 18, as shown in fig. 3A and 3B. In this application, the field of view 15a of the rear-view camera 10a can be dynamically changed without reducing the resolution of the image output from the rear-view camera 10 a. For example, the field of view may be moved to keep an image of any detected vehicle within the image. Further, as shown in fig. 3A and 3B, the field of view may be widened or narrowed depending on whether the vehicle is in reverse (for RCD) or in forward (for FDM), or depending on the forward speed of the vehicle or the type of road on which the vehicle is traveling. Thus, a single camera may be used for both RCD and FDM applications. Note that the rear view camera 10a may be located behind or to the side of the vehicle as cameras 10a ', 10a "with respective variable fields of view 15 a', 15 a". The images captured by the rear view cameras 10a, 10a', and 10a "may be displayed on a display located in the rear view mirror 16 or elsewhere in the dashboard or console. Additionally or alternatively, the images may be processed for autonomous vehicle control or driver assistance functions, such as parking assistance, blind spot detection, rear collision warning, lane departure warning, lane keeping assistance, and the like.

Another example of a vehicle application for the imaging system 10 would be a forward looking camera 10b as shown in fig. 3A. This front view camera 10b may be mounted at or near the rear view mirror 16 to capture images of the front of the vehicle through its windshield. Images captured by the forward looking camera 10b may be used for many different driver assistance functions or autonomous vehicle control functions. For example, the images may be used for headlight control, lane departure warning, parking assist, adaptive cruise control, lane keeping assist, forward collision warning, object detection, pedestrian detection, and traffic sign recognition. However, for each of these functions, it may be desirable to use a wider or narrower field of view 15b in order to limit the information in the captured image to information related to the particular function. Thus, providing the electrowetting lens 30 in the front view camera 10b provides the advantage of changing the field of view for the selected function without loss of resolution. Furthermore, the ability of the electrowetting lens to move the field of view 15b to the left or right allows the forward looking camera 10b to view in the direction of an upcoming turn.

When used for headlamp control, the forward looking camera 10b may advantageously maintain a high number of pixels per degree of field of view as the field of view narrows to focus on distant objects. This allows more accurate detection of vehicles and other objects at greater distances. Likewise, the field of view may be changed to look in the direction of an upcoming turn so that the vehicle on the turn may be detected more quickly and accurately.

Another example of a vehicle application for the imaging system 10 would be an interior view camera 10c as shown in fig. 3A. This inward looking camera 10c may be mounted at or near the rear view mirror 16, overhead console or reading light assembly in order to capture images of the interior of the vehicle and display the images to the driver or other passengers. For example, such a camera 10c may be mounted to view a rear seat occupant and display images to the driver on a display that may be mounted in the rear view mirror 16 or elsewhere in the dashboard or console. This is particularly useful if one of the passengers is an infant, and even more advantageous if the infant is located in a rear facing car seat. By employing an electrowetting lens in the inward-looking camera 10c, the field of view 15c may be moved around the interior of the vehicle in order to view a particular passenger or location in the vehicle. The field of view 15c may also be widened or narrowed to capture front seat passengers or focus on rear seat passengers. Such a change in the field of view 15c may be achieved by manual or automatic control by the driver. Automatic control may be used for video conferencing to move the field of view to the vehicle occupant who is speaking.

By using the zoom lens 30 in the imaging system 10 used in a vehicle, relying only on digital zooming to change the field of view can be avoided, which results in a reduced resolution of the image captured by the system. Furthermore, to some extent, it is desirable to avoid this by providing a mechanical zoom lens that is more complex to manufacture and susceptible to breakage.

If the zoom lenses 30, 30a oscillate between two or more images or fields of view, a first image stream having a first field of view may be supplied to the first display 50a and a second image stream having a different second field of view may be supplied to the second display 50b, and thus two or more different image streams may be captured and displayed in real time. Different image streams may also be displayed in different display areas of one display 50 a. The use of one camera to collect multiple images is preferred over the use of multiple cameras. For example, if the camera is set to oscillate between two images at a frequency of 30Hz, one can update two different images on two different displays or two different display areas at a frequency of 15 Hz.

The imaging system 10 may also find advantageous application in security cameras, particularly those where two separate image sensors are used to capture retinal images of both eyes of a person. By using the electrowetting lens 30, the field of view can be moved from one eye to the other, and thereby eliminating the need for two separate cameras. Further, the field of view may be initially set wide to capture a person's face and identify the location of his eyes, and then zoom in on each eye. This will make it more practical to implement bio-screening security measures (especially retinal imaging) in mobile devices, as mobile devices typically have only one camera aimed in either direction.

Security cameras with variable field of view electrowetting lenses can be used in home security systems as well as smoke detectors and flash lighting devices. Similarly, a vehicle camera, such as camera 10c, may be used for safety purposes to scan the iris of the driver before starting the vehicle. The imaging system may also be used to scan a human face for use in a facial recognition system.

Although the imaging system 10 is shown with only the electrowetting lens 30 in front of the image sensor 20, additional conventional lenses may be used in conjunction with the electrowetting lens 30 to obtain the desired field of view and focus. Further, other forms of zoom lenses may be used in combination with the HD image sensor 20. An example of an electrowetting lens that can be used is available from Invenios (Santa Barbara, Calif.). Such a lens may provide a 130 ° FOV for RCD applications and a 50 ° FOV for FDM applications under sharp images.

It should further be noted that the controller 40 may include various forms of control logic and image processing circuitry. To properly handle both the FDM and RCD FOVs, a distortion correction engine may be provided in the controller 40. To use the analog HD image sensor 20, one may want to reduce the resolution of the transmission so that Image Signal Processing (ISP) can be performed in the camera module (HDR reconstructor, windowing, etc.). Accordingly, an ISP processor (e.g., GEO Semi GW5) with distortion correction may be provided in the camera module portion of imaging system 10, which would include HD image sensor 20, zoom lens 30, and controller 40, and have an analog output from the camera.

The above description is considered that of the preferred embodiments only. Modifications of the invention will occur to those skilled in the art and to those who make or use the invention. Therefore, it is to be understood that the embodiments shown in the drawings and described above are merely for illustrative purposes and are not intended to limit the scope of the invention, which is defined by the following claims as interpreted according to the principles of patent law and the doctrine of equivalents.