Patent Publication Number: US-9852332-B2

Title: Object recognition in low-lux and high-lux conditions

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 15/054,503 filed on Feb. 26, 2016, which is a continuation of U.S. application Ser. No. 14/300,569 filed on Jun. 10, 2014 and now issued as U.S. Pat. No. 9,302,621, which is a continuation of U.S. application Ser. No. 13/659,826, filed Oct. 24, 2012 and now issued as U.S. Pat. No. 8,781,171, all of which are expressly incorporated herein by reference. 
    
    
     BACKGROUND 
     Field of Disclosure 
     The disclosure generally relates to object recognition, in particular to object recognition in low-lux and high-lux conditions in a vehicle. 
     Description of the Related Art 
     Image sensors are used to capture image data for objects in various different environments. Moreover, the image sensors or additional equipment are adjusted to best suit the environment being monitored. For example, in an environment with low illumination, i.e. low-lux level, an image sensor may be supplemented by an illumination source that provides constant illumination. While such adjustments work well for static environments, these adjustments do not address the challenges presented by a dynamic environment. For example, an image sensor monitoring objects within a vehicle and adjusted for a particular illumination level may not be effective when the illumination level within the vehicle drops because the vehicle is passing through a dark spot or is being driven during the night. 
     BRIEF DESCRIPTION 
     Embodiments of the invention capture image data for gestures from a passenger or a driver in a vehicle with a dynamic illumination level. The disclosed system comprises a low-lux sensor equipped to capture image data in an environment with an illumination level below an illumination threshold, a high-lux sensor equipped to capture image data in the environment with the illumination level above the illumination threshold, and an object recognition module for activating and deactivating the sensors. The low-lux and high-lux sensors are located in an overhead console of the vehicle. 
     The object recognition module determines the illumination level of the environment and determines whether the illumination level is below the illumination level threshold. If the illumination level is below the threshold, the object recognition module activates the low-lux sensor. In one embodiment, the object recognition module also activates an illumination source with activation of the low-lux sensor. The illumination source illuminates the environment for the low-lux sensor and enables the low-lux sensor to capture image data at the low illumination level. If the illumination level is above the threshold, the object recognition module activates the high-lux sensor. In one embodiment, the high-lux sensor includes an infrared filter to reduce the amount of infrared light reaching the high-lux sensor. 
     Other embodiments of the invention include a computer-readable medium that store instructions for implementing the above described functions of the system, and a computer-implemented method that includes steps for performing the above described functions. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram illustrating a computing environment for capturing image data in an environment with dynamic illumination level according to one embodiment. 
         FIG. 2  is a block diagram illustrating an object recognition module in the computing environment for capturing image data in an environment with dynamic illumination level according to one embodiment. 
         FIG. 3  is a flow diagram illustrating a method for capturing image data in an environment with dynamic illumination level according to one embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The computing environment described herein captures image data representing gestures from a driver or a passenger in low-lux and high-lux conditions in a vehicle. The figures and the following description describe certain embodiments by way of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles described herein. Reference will now be made in detail to several embodiments, examples of which are illustrated in the accompanying figures. It is noted that wherever practicable similar or like reference numbers may be used in the figures and may indicate similar or like functionality. 
     System Environment 
     Referring to  FIG. 1 , the computing environment  100  for capturing image data in an environment with dynamic illumination level comprises an object recognition module  102 , a pair of low-lux image sensors  104   a - b  (e.g., infrared sensors), a pair of high-lux image sensors  106   a - b  (e.g., RGB sensors), an illumination level detector  110 , and a communication module  112 . Although the illustrated computing environment  100  includes two low-lux image sensors  104   a - b  and two high-lux image sensors  106   a - b,  other embodiments of the computing environment  100  may include one or more of the low-lux image sensors  104   a - b  and high-lux image sensors  106   a - b . Additionally, in one embodiment, the computing environment  100  is present within a vehicle or a mobile cabin. The computing environment  100  may also be located in other environments that have a dynamic illumination level. 
     The illumination level detector  110  is a device that measures the amount of light present in the environment  100 . In one embodiment, the illumination level detector  110  includes photovoltaic sensors that convert light into electricity that can be measured. The illumination level detector  110  measures the amount of electricity produced and determines the amount of light or the illumination level for the environment based on the measured electricity. In one embodiment, the illumination level detector employs the principles of light meters like the reflected-light meters or the incident-light meters to measure the illumination level in the environment  100 . 
     The object recognition module  102  receives the measured illumination level from the illumination level detector  110 , determines whether the illumination level is beyond a lux threshold, and activates the high-lux image sensors  106   a - b  or the low-lux image sensors  104   a - b  based on the determination. In one embodiment, the object recognition module  102  activates the low-lux image sensors  104   a - b  in response to determining that the illumination level is below the lux threshold, and activates the high-lux image sensors  106   a - b  in response to determining that the illumination level is equal to or above the lux threshold. In another embodiment, the object recognition module  102  ensures that both low-lux and high-lux sensors  104   a - b,    106   a - b  are not active at the same time. Accordingly, in response to activating low-lux sensors  104   a - b,  the object recognition module  102  deactivates any active high-lux sensors  106   a - b  and vice versa. The object recognition module  102  then receives image data from the activated sensors  104 ,  106 , processes the received image data, and recognizes an object in the image based on the processing. In one embodiment, the recognized object is a person performing a particular gesture, and the object recognition module  102  performs a function like communicating with a user through the communication module  112  based on the recognized object. 
     The selective activation by object recognition module  102  of the low-lux sensors  104   a - b  and the high-lux sensors  106   a - b  beneficially enables the object recognition module  102  to capture data both in low-lux conditions (i.e. conditions when the environment  100  includes low amount of light) and in high-lux conditions (i.e. conditions when the environment  100  includes adequate or high amount of light). Accordingly, the object recognition module  102  can be beneficially used in environments with dynamic illumination levels to capture and process image data. 
     The communication module  112  provides an interface between a user and the object recognition module  102 . The communication module  112  therefore comprises an output device and optionally an input device for communication with the user. Examples of output devices include a touch screen for visual communication and an audio device for audio communication. Examples of input devices include a touch screen, a mouse, and a keypad. 
     The high-lux sensors  106   a - b  are image sensors capable of capturing image data at an illumination level above or equal to the lux threshold. Examples of such high-lux sensors  106   a - b  include charge-coupled device (CCD) sensors or complementary metal-oxide-semiconductor (CMOS) sensors that have the appropriate sensitivity to light, i.e. luminance range, to capture image data in presence of illumination level above or equal to the lux threshold. Luminance range of an image sensor  106   a  is the range of the scene luminance under which the sensors  106   a - b  is equipped to capture image data. For example, luminance range of the high-lux sensors  106   a - b  can be 300-1000 candela per square meter or 1000-12000 Lux. 
     In one embodiment, the high-lux sensors  106   a - b  are color image sensors that capture image data to reproduce a colored image of environment  100 . These color high-lux sensors  106   a - b  may optionally be used with an infrared blocking filter to reduce or minimize any distortions caused by light with infrared wavelengths. In one embodiment, the two high-lux sensors  106   a - b  are located at an interocular distance (i.e. the approximate distance between a person&#39;s eyes) from each other to capture three-dimensional images for stereo image processing. 
     The low-lux sensors  104   a - b  are image sensors capable of capturing image data at an illumination level below the lux threshold. Examples of such low-lux sensors  104   a - b  include CCD or CMOS sensors that have the appropriate luminance range to capture image data in presence of illumination level below the lux threshold. In one embodiment, the low-lux image sensors have a luminance range of 25-350 candelas per square meter or 0-80 Lux. In one embodiment, the two low-lux sensors  104   a - b  are located at an interocular distance from each other to capture three-dimensional images for stereo image processing. In one embodiment, the luminance range of low-lux sensors  104   a - b  is different from the luminance range of high-lux sensors  106   a - b.  The different luminance ranges enable the low-lux sensors to better capture image data at lower illumination levels and enable the high-lux sensors to better capture image data at higher illumination levels. In another embodiment, the luminance range for the low-lux image sensors  104   a - b  and high-lux image sensors  106   a - b  is the same. 
     In one embodiment, the low-lux image sensors  104   a - b  have associated illumination sources  108   a - b  that illuminate the field of view of the low-lux image sensors  104   a - b . Examples of image sensors with associated illumination sources include DEFENDER SPARTAN5 night vision camera and CCTV EX11DXL dual sensor color night vision camera. Moreover, in one embodiment as described below, the illumination sources  108   a - b  emit a light with a spectrum that includes a single wavelength or similar wavelengths. In this embodiment, the low-lux sensors  104   a - b  are monochrome image sensors that are efficient in converting received light with wavelengths similar to the wavelengths of the light emitted by the illumination sources  108   a - b . These monochrome low-lux sensors  104   a - b  are beneficially adept at capturing image data at low illumination levels. 
     In one embodiment, the illumination sources  108   a - b  emit infrared light to illuminate the scene, and the low-lux sensors  104   a - b  in this embodiment do not include an infrared filter to reduce or minimize the infrared light reaching the low-lux sensors  104   a - b . Because the illumination sources  108   a - b  are illuminating the scene with an infrared light, the lack of infrared filter beneficially enables the low-lux sensors  104   a - b  to capture image data when the environment  100  is illuminated with the infrared light. 
     The illumination sources  108   a - b,  in one embodiment, are included in or attached to the low-lux image sensors  104   a - b . In other embodiments of the environment  100 , illumination sources  108   a - b  are physically separate from the low-lux image sensors  104   a - b.    
     The illumination sources  108   a - b,  in one embodiment, are near infrared (NIR) light emitting diodes (LEDs) that emit near infrared light to illuminate the field of view of the sensors  104   a - b . Because the NIR light is invisible to humans, the NIR light beneficially illuminates the field of view without distracting the humans in the environment  100 . In the case where the environment  100  being illuminated is within a vehicle, illuminating the environment  100  without distracting the driver is desirable. In another embodiment, the illumination sources  108   a - b  emit light other than NIR light to illuminate the field of view. Additionally, in one embodiment, the illumination sources  108   a - b  emit light with a spectrum including a single wavelength or similar wavelengths because illuminating the field of view with such light beneficially reduces the chromaticity of the image resulting from data captured by the low-lux image sensors  104   a - b.    
     In another embodiment, the illumination sources  108   a - b  emit light with a band of spectrum that lies within a range at the peak of the response curve of the low-lux image sensors  104   a - b . The response curve of an image sensor indicates the sensor&#39;s efficiency in generating current per amount of light received by the sensor at different wavelengths. Accordingly, the illumination sources  108   a - b  emit light with a spectrum band that includes wavelengths at which the low-lux image sensors  104   a - b  produce a high amount of current per amount of light received by the sensors  104   a - b.  For example, the illumination sources  108   a - b  emit light with wavelengths between 750 nanometers (nm) and 900 nm because the low-lux sensors  104   a - b  produce 0.2-0.275 amps per watts (A/W) for light received in these wavelengths and generally produce lesser current for light at other wavelengths. 
     The illumination sources  108   a - b,  the low-lux sensors  104   a - b  and the high-lux sensors  106   a - b  are optionally physically located above a region being monitored in the environment  100 . The higher location of the sensors  104   a - b,    106   a - b  beneficially provides the sensors  104   a - b,    106   a - b  a substantially unobstructed view of the monitored region. For example, when the environment  100  is located within a vehicle and the region being monitored is the region around the driver or a passenger, the sensors  104   a - b,    106   a - b  and illumination sources  108   a - b  are located in an overhead console above the center console between the driver seat and passenger seat. In addition to a substantially unobstructed view, the location of the sensors  104   a - b,    106   a - b  in the vehicle reduces any undesirable effects of direct incident light entering the vehicle from the front windshield. 
     Additionally, in one embodiment, the illumination sources  108   a - b  are located adjacent to the sensors  104   a - b,  and the illumination sources  108   a - b  illuminate the region in front of the sensors  104   a - b . Because the illumination sources  108   a - b  are located adjacent, and not opposite, to the sensors, direct incident light from illumination sources  108   a - b  on sensors  104   a - b  is beneficially minimized. 
     Object Recognition Module 
       FIG. 2  is a block diagram illustrating an object recognition module  102  in the computing environment for capturing image data in an environment with a dynamic illumination level according to one embodiment. The object recognition module  102  comprises an illumination level module  202 , an illumination threshold module  204 , a capture source module  206 , an illumination source module  208 , an image data storage  210  and an image processing module  212 . 
     The illumination level module  202  is communicatively coupled to the illumination level detector  110  and the illumination level module  202  determines the illumination level measured by the detector  110 . In one embodiment, the illumination level module  202  repeatedly polls the illumination level detector  110  to determine the measured illumination level. In another embodiment, the illumination level detector  110  is configured to repeatedly transmit the measured illumination level and the illumination level module  202  receives the transmitted illumination level. In yet another embodiment, the illumination level module  202  receives a threshold number of illumination level measurements or receives illumination level measurements for a threshold amount of time, and the illumination level module  202  determines the illumination level based on the received readings. For example, the illumination level may determine the average of the received readings as the illumination level. Such determination based on multiple illumination level measurements beneficially enable the object recognition module  102  to account for any outlier readings that may be caused because of a temporary malfunction of the detector  110  or a temporary obstacle in front of the detector  110 . 
     The illumination threshold module  204  receives the determined illumination level from the illumination level module  202  and determines whether the determined illumination level is beyond a lux threshold. In one embodiment, the lux threshold is configurable and a user or a module may provide the appropriate lux threshold through a user interface to the illumination threshold module  204 . In one embodiment, the lux threshold is based on the luminance range of the low-lux image sensors  104   a - b  or the high-lux image sensors. For example, the lux threshold is set to a value within the overlap of the luminance ranges of the low-lux sensors  104   a - b  and high-lux sensors  106 . Accordingly, if the luminance range for low-lux sensors  104   a - b  is 25-350 candelas per square meter and the luminance range for high-lux sensors  106   a - b  is 300-1000 candela per square meter, the lux threshold may be set to 325 candelas per square meter. Such a lux threshold beneficially ensures that the current illumination level is within the luminance range of the sensors  104 ,  106  when either of the sensors  104 ,  106  are activated. 
     The capture source module  206  activates the low-lux sensors  104   a - b  or the high-lux sensors  106   a - b  based on the determination made by the illumination threshold module  204 . If the illumination threshold module  204  determines that the illumination level is beyond or equal to the lux threshold, the capture source module  206  activates the high-lux sensors  106   a - b . Otherwise, the capture source module  206  activates the low-lux sensors  104   a - b . In one embodiment, the capture source module  206  deactivates the low-lux sensors  104   a - b  when the capture source module  206  activates the high-lux sensors  106   a - b  and vice versa. Such deactivation beneficially ensures that the image data is being captured by the appropriate sensors suited for the current lux condition of the environment  100 . 
     The illumination source module  208  controls the activation and deactivation of the illumination sources  108   a - b . In one embodiment, the illumination source module  208  is in communication with the capture source module  206  and the illumination source module  208  activates and deactivates the illumination sources  108   a - b  responsive to the capture source module  206  activating and deactivating the low-lux sensors  104   a - b . In another embodiment, the illumination source module  208  activates and deactivates the illumination sources  108   a - b  based on the determination made by the illumination threshold module  204 . If the illumination threshold module  204  determines that the illumination level is equal to or beyond the lux threshold, the illumination source module  208  deactivates any active illumination sources  108   a - b.  Otherwise, the illumination source module  208  activates the illumination sources  108   a - b . The activated illumination sources  108   a - b  beneficially illuminate the field of view of the low-lux sensors  104   a - b.    
     The image data storage  210  is a volatile or non-volatile storage that receives and stores the image data captured by the image sensors  104   a - b,    106   a - b.  In one embodiment, the image data storage  210  stores separately the image data from the low-lux sensors  104   a - b  and the high-lux sensors  106   a - b . The separately stored image data enables the image processing module  212  to process the image data from the two different types of sensors  104   a - b,    106   a - b  in different manners as needed. 
     The image processing module  212  processes the image stored in image data storage  210 , recognizes an object based on the processing, and initiates a response based on the recognized object. The image processing module  212  may implement a technique like stereoscopic image processing technique to process the data and recognize an object. An example of such a technique is described in scholarly paper titled “Stereoscopic Image Processing” (available at http://dsp-book.narod.ru/DSPMW/57.PDF), which is incorporated by reference herein in its entirety. Based on the recognized object, the image processing module  212  determines and initiates an appropriate response. For example, the image processing module  212  may process the stored image data and determine that the stored image data indicates a human is performing a particular gesture. In response to this determination, the image processing module  212  queries a database (not shown) and determines a user request associated with the gesture. The image processing module  212  then directs the appropriate processes to take appropriate action in response to the determined request. For example, if the request indicates that the user wants to instruct an audio player to play a particular music file, the image processing module  212  communicates with the music player and instructs the player to play the music file. Additional examples of requests associated with various gestures include requesting activation or deactivation of a light within a car, requesting an application in the vehicle, like Global Positioning System, to be activated or deactivate, and requesting a driving feature like cruise control to be activated or deactivated. 
     Object Recognition Methodology 
       FIG. 3  is a flow diagram illustrating a method for capturing image data in an environment with dynamic illumination level according to one embodiment. The object recognition module  102  determines  302  the illumination level in the environment  100  and determines  304  whether the illumination level is below a lux threshold. If the illumination is below the lux threshold, the object recognition module  102  activates  306  the low-lux sensors  104   a - b  and optionally the illumination sources  108   a - b . In one embodiment, the object recognition module  102  also deactivates  306  any active high-lux sensors  106   a - b  with activation of the low-lux sensors  104   a - b.    
     If the determined illumination level is not below the lux threshold, the object recognition module  102  activates  308  the high-lux sensors  106   a - b . Additionally, in one embodiment, the object recognition module  102  deactivates any active low-lux sensors  104   a - b  and illumination sources  108   a - b  with activation of the high-lux sensors  106   a - b . The object recognition module  102  then captures  310  and processes  312  image data. In one embodiment, as the illumination level repeatedly varies to levels above and below the lux threshold, the object recognition module  102  repeatedly activates the high-lux sensors  106   a - b  and the low-lux sensors  104   a - b . The object recognition module  102  captures data from the sensors  104   a - b,    106   a - b  and processes the captured data. In another embodiment, the high-lux sensors  106   a - b  and the low-lux sensors  104   a - b  are constantly active, and the object recognition module  102  captures data from either of the sensors based on the illumination level. If the illumination level is below the lux threshold, the object recognition module  102  captures and processes data from the low-lux sensors  104   a - b . Otherwise, the object recognition module  102  captures and processes data from the high-lux sensors  106   a - b.  Accordingly, the recognition module  102  is capable of capturing and processing data in conditions with varying lux levels like a vehicle driving through a tunnel wherein the lux level increases and decreases as the vehicle enters and exits the tunnel. Based on the processing, the object recognition module  102  recognizes  314  an object in the image and initiates an appropriate response. 
     The foregoing description of the embodiments of the invention has been presented for the purpose of illustration; it is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Persons skilled in the relevant art can appreciate that many modifications and variations are possible in light of the above disclosure. 
     Some portions of this description describe the embodiments of the invention in terms of algorithms and symbolic representations of operations on information. These algorithmic descriptions and representations are commonly used by those skilled in the data processing arts to convey the substance of their work effectively to others skilled in the art. These operations, while described functionally, computationally, or logically, are understood to be implemented by computer programs or equivalent electrical circuits, microcode, or the like. Furthermore, it has also proven convenient at times, to refer to these arrangements of operations as modules, without loss of generality. The described operations and their associated modules may be embodied in software, firmware, hardware, or any combinations thereof. One of ordinary skill in the art will understand that the hardware, implementing the described modules, includes at least one processor and a memory, the memory comprising instructions to execute the described functionality of the modules. 
     Any of the steps, operations, or processes described herein may be performed or implemented with one or more hardware or software modules, alone or in combination with other devices. In one embodiment, a software module is implemented with a computer program product comprising a non-transitory computer-readable medium containing computer program code, which can be executed by a computer processor for performing any or all of the steps, operations, or processes described. 
     Embodiments of the invention may also relate to an apparatus for performing the operations herein. This apparatus may be specially constructed for the required purposes, and/or it may comprise a general-purpose computing device selectively activated or reconfigured by a computer program stored in the computer. Such a computer program may be stored in a non-transitory, tangible computer-readable storage medium, or any type of media suitable for storing electronic instructions, which may be coupled to a computer system bus. Furthermore, any computing systems referred to in the specification may include a single processor or may be architectures employing multiple processor designs for increased computing capability. 
     Embodiments of the invention may also relate to a product that is produced by a computing process described herein. Such a product may comprise information resulting from a computing process, where the information is stored on a non-transitory, tangible computer-readable storage medium and may include any embodiment of a computer program product or other data combination described herein. 
     Finally, the language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based hereon. Accordingly, the disclosure of the embodiments of the invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims. 
     It will be appreciated that various of the above-disclosed and other features and functions, or alternatives or varieties thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.