OPTICAL DETECTION APPARATUS AND METHODS

• US 20160004923A1
• Filed: 07/01/2014
• Published: 01/07/2016
• Est. Priority Date: 07/01/2014
• Status: Active Grant

• Current Assignee: Brain Corporation
• Original Assignee: Brain Corporation
• Inventors: Piekniewski, Filip, Polonichko, Vadim, Izhikevich, Eugene
• Granted Patent: US 9,848,112 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60W 30/09 Taking automatic action to avoid collision, e.g. braking and steering
• CPC Class Codes: B60W 30/14 Adaptive cruise control
• CPC Class Codes: B60W 30/16 Control of distance between vehicles, e.g. keeping a distance to preceding vehicle
• CPC Class Codes: G01C 3/08 Use of electric radiation detectors
• CPC Class Codes: G02B 13/0015 characterised by the lens design
• CPC Class Codes: G02B 27/0075 with means for altering, e.g. increasing, the depth of field or depth of focus
• CPC Class Codes: G02B 5/204 in which spectral selection is performed by means of a conductive grid or array, e.g. frequency selective surfaces for use with wavelengths longer than the infrared light H01Q15/0006
• CPC Class Codes: G02B 7/38 measured at different points on the optical axis , e.g. focussing on two or more planes and comparing image data
• CPC Class Codes: G06V 10/431 Frequency domain transformation; Autocorrelation
• CPC Class Codes: G06V 10/446 using Haar-like filters, e.g. using integral image techniques
• CPC Class Codes: G06V 20/00 Scenes; Scene-specific elements control of digital cameras H04N23/60
• CPC Class Codes: G06V 20/10 Terrestrial scenes scenes under surveillance with static cameras G06V20/52; scenes perceived from the exterior of a vehicle G06V20/56; scenes perceived from the interior of a vehicle G06V20/59
• CPC Class Codes: G06V 20/56 exterior to a vehicle by using sensors mounted on the vehicle
• CPC Class Codes: G06V 20/584 of vehicle lights or traffic lights
• CPC Class Codes: H01L 31/02162 for filtering or shielding light, e.g. multicolour filters for photodetectors
• CPC Class Codes: H04N 23/45 for generating image signals from two or more image sensors being of different type or operating in different modes, e.g. with a CMOS sensor for moving images in combination with a charge-coupled device [CCD] for still images
• CPC Class Codes: H04N 23/54 Mounting of pick-up tubes, electronic image sensors, deviation or focusing coils
• CPC Class Codes: H05K 999/99 dummy group

Abstract

An optical object detection apparatus and associated methods. The apparatus may comprise a lens (e.g., fixed-focal length wide aperture lens) and an image sensor. The fixed focal length of the lens may correspond to a depth of field area in front of the lens. When an object enters the depth of field area (e.g., sue to a relative motion between the object and the lens) the object representation on the image sensor plane may be in-focus. Objects outside the depth of field area may be out of focus. In-focus representations of objects may be characterized by a greater contrast parameter compared to out of focus representations. One or more images provided by the detection apparatus may be analyzed in order to determine useful information (e.g., an image contrast parameter) of a given image. Based on the image contrast meeting one or more criteria, a detection indication may be produced.

Claims

1. A non-transitory computer-readable storage medium having instructions embodied thereon, the instructions being executable on a processing apparatus to detect an object in an image by at least:

producing a high-pass filtered version of the image, the high-pass filtered version comprising a plurality of pixels;

for at least some of the plurality of pixels, determining a deviation parameter between the value of a given pixel and a reference value; and

based on the deviation parameter meeting a criterion, providing an indication of the object being present in the image.

2. The non-transitory medium of claim 1, wherein:

the high-pass filtered version of the image is produced based at least on a first convolution operation between a kernel and the image, the kernel characterized by a kernel dimension; and

the convolution operation is configured to reduce energy-associated spatial scales in the image that are lower than the kernel dimension.

3. The non-transitory medium of claim 2, wherein:

the kernel is configured based at least on a second convolution operation of a first matrix, the first matrix configured based at least on a Laplacian operator, and a second matrix configured based at least on a Gaussian operator; and

the image is characterized by image dimension, the image dimension exceeding the kernel dimension by at least ten times (10×

).

4. The non-transitory medium of claim 2, wherein

the high-pass filtered version of the image is further produced based on a difference between the image and a smoothed version of the image,

the smoothed version of the image obtained using one or more smoothing operations applied to the image.

5. The non-transitory medium of claim 2, wherein

the reference value comprises a mean or median brightness of the image;

and

the deviation parameter comprises a maximum absolute value of a difference between a given pixel value and the reference value.

6. The non-transitory medium of claim 2, wherein the contrast parameter is determined based at least on a temporal average of a plurality of contrast parameters, individual ones of the plurality of contrast parameters corresponding to a plurality of images.

7. The non-transitory medium of claim 1, wherein the criterion comprises meeting or exceeding a prescribed threshold.

8. An optical object detection apparatus comprising:

a lens characterized by a depth of field range;

an image sensor configured to provide an image comprising one or more pixels; and

a logic in communication with the image sensor and configured to;

evaluate at least a portion of the image to determine an image contrast parameter; and

produce an object detection indication based on the contrast parameter meeting one or more criteria, the object indication configured to convey presence of the object within the depth of field range.

9. The apparatus of claim 8, wherein:

the image sensor comprises an array of photo-sensitive elements arranged in a plane disposed substantially parallel to the lens; and

individual pixels being produced by individual ones of the photo-sensitive elements.

10. The apparatus of claim 9, wherein:

the array of photo-sensitive elements comprises elements operable to respond to a first wavelength and a second wavelength of electromagnetic energy;

the elements operable for the first wavelength are configured to respond to a first object representation disposed at a first distance from the lens; and

the elements operable for the second wavelength are configured to respond to a second object representation disposed at a second distance from the lens, the second distance being smaller than the first distance.

11. The apparatus of claim 8, wherein the image sensor comprises two or more arrays of photo-sensitive elements disposed in first and second plane, the first plane being parallel to the lens, the second plane being oblique to the lens.

12. The apparatus of claim 8 wherein the image sensor comprises an array of photo-sensitive element s disposed in a plane inclined to the lens.

13. The apparatus of claim 8, wherein the image sensor comprises an array of photo-sensitive elements disposed in a plane perpendicular to the lens plane.

14. The apparatus of claim 8, wherein:

image sensor comprises an array of photo sensitive elements arranged in a plane parallel to the lens; and

the image is characterized by an image dimension, the image dimension corresponding to a first resolvable spatial scale;

individual pixels of the one or more pixels are characterized by a pixel dimension, the pixel dimension corresponding to a second resolvable spatial scale; and

the determination of the image contrast parameter comprises;

determination of a two dimensional distribution of energy content within a plurality of groups of pixels of the image, individual ones of the plurality of groups of pixels characterized by a scale of a plurality of spatial scales;

partition of the two dimensional distribution into a first portion and a second portion; and

evaluation of the first portion two dimensional distribution of energy content.

15. The apparatus of claim 14, wherein:

the first resolvable spatial scale comprises a largest spatial scale in the image;

the first portion comprises an inner portion encompassing the largest spatial scale;

the two dimensional distribution of energy content comprises a plurality of components corresponding to individual ones of the plurality of spatial scales; and

evaluation of the inner portion comprises a comparison of a first sum of components within the inner portion to a second sum of components within the second portion of the two dimensional distribution.

16. The apparatus of claim 14, wherein:

the determination of a two dimensional distribution of energy content is based at least in part on performance of a two dimensional Fourier transform operation on the image;

partition of the distribution is configured based on a curve in scale space characterized by a range from the first resolvable spatial scale; and

evaluation of the first portion comprises a determination of a ratio of a first sum of components within the first portion to a second sum of components within the second portion of the two dimensional distribution.

17. The apparatus of claim 8, wherein the determination of the image contrast parameter comprises:

a determination of a high-pass filtered version of the image configured based on a convolution operation between a kernel and the image, the high passed version comprising a plurality of pixels; and

for a given pixel of the plurality of pixels, a determination of a deviation parameter between value of the given pixel and a reference value.

18. A method of navigating a trajectory by a robotic apparatus comprising a controller, an actuator and a sensor, the method comprising:

obtaining at least one image associated with surroundings of the apparatus using the sensor;

analyzing the at least one image to determine a contrast parameter of the image;

detecting a presence of an object in the at least one image based at least in part on the contrast parameter meeting one or more criteria; and

causing the controller to activate the actuator based on the detection of the presence of the object;

wherein the actuator activation is configured consistent with a characteristic of the object.

19. The method of claim 18, wherein:

the robotic device comprises a vehicle;

the object comprises one of a target or an obstacle; and

the actuator activation is configured to cause the vehicle to perform at least one of a target approach or obstacle avoidance action.

20. The method of claim 19, wherein:

the object characteristic comprises a distance of the camera to the object;

for the target approach action the actuator activation is configured to reduce the distance; and

for the obstacle avoidance action the actuator activation is configured to increase the distance.

21. The method of claim 19, wherein:

the trajectory is characterized by motion direction;

the object characteristic comprises object location with respect to the camera;

for the target approach action the actuator activation is configured to adjust the motion towards the location; and

for the obstacle avoidance action the actuator activation is configured to adjust the motion away the location.

23. The method of claim 21, wherein the selective activation comprises activation of one or more actions by the actuator which will cause the apparatus to either increase or decrease its proximity to the object.

22. A method of navigating a robotic apparatus comprising a controller, an actuator and a sensor, the method comprising:

obtaining at least one image associated with surroundings of the apparatus using the sensor;

analyzing the at least one image to detect a presence of an object in the at least one image;

determining that the detected object comprises one of either a target or an obstacle; and

causing the controller to selectively activate the actuator based on the determination.