Patent Description:
Some references, which may include patents, patent applications and various publications, may be cited and discussed in the description of this disclosure. The citation and/or discussion of such references is provided merely to clarify the description of the present disclosure The following documents:.

The present disclosure relates to a method for image recognition, and more particularly to a preprocessing method for improving image recognition.

Currently, some vehicles are configured to include an adaptive driving beam (ADB). The adaptive driving beam is capable of controlling each of light and dark regions such as to correspond to positions of oncoming vehicles and vehicles ahead through cooperation of software, firmware and hardware, so as to avoid causing discomfort to drivers of the oncoming vehicles and the vehicles ahead by emitting strong light.

However, it is difficult to precisely recognize an illuminating object during nighttime. The illuminating object in the night may be self-illuminating objects or light-reflecting objects. For example, the self-illuminating objects can be headlamps of a vehicle, and the light-reflecting objects can be pedestrians or other vehicles on the road. In current technologies, although an image of an illuminating object in front of a vehicle can be recognized, but under severe weather conditions such as rain or fog, recognizing the image becomes more difficult and sometimes even impossible. The illuminating object needs to be clearly recognized, so that appropriate processing may be performed accordingly.

Therefore, it has become an important issue in the field to apply an effective image preprocess, so as to improve image recognition during nighttime and reduce misjudgments.

In response to the above-referenced technical inadequacies, the present disclosure provides a preprocessing method for improving image recognition according to independent claim <NUM>. The dependent claims show further embodiments of the image capturing module of claim <NUM>.

In one aspect, the present disclosure provides a preprocessing method for improving image recognition, the preprocessing method being applied to recognize a target object in front of a driver's vehicle that being driven under dim light or severe weather conditions, the target object emitting a light with a color temperature of <NUM>, the method being implemented through a preprocessing system for improving image recognition rate, the preprocessing system including an image sensor and at least one light emitting diode, the preprocessing method comprising: disposing the at least one light-emitting diode to surround the image sensor, in which the image sensor has an image capture region; turning on the at least one light-emitting diode, such that the at least one light-emitting diode emits at least one white light source having a color temperature of <NUM>, in which the at least one white light source has a fixed illumination area range, and the illumination area range covers the image capture region, so that a color temperature of the image capture region is approximately or equal to <NUM>; turning off the at least one light-emitting diode for a time interval, such that the image sensor captures images to generate a preprocessing frame under a low illuminance condition between <NUM> lux and <NUM> lux; and alternatingly turning on and off the light-emitting diode, such that the image sensor generates a plurality of the preprocessing frames for image recognition processing.

One of the beneficial effects of the present disclosure is that, by virtue of "disposing at least one light-emitting diode to surround an image sensor, in which the image sensor corresponds to an image capture region", "turning on the at least one light-emitting diode, such that the at least one light-emitting diode emits at least one white light source having a color temperature of <NUM>, in which the at least one white light source has a fixed illumination area range, and the illumination area range covers the image capture region, so that a color temperature of the image capture region is approximately or equal to <NUM>", and "turning off the at least one light-emitting diode for a time interval, such that the image sensor captures images to generate a preprocessing frame under a low illuminance condition between <NUM> lux and <NUM> lux", the preprocessing method for improving image recognition provided in the present disclosure is capable of improving image recognition during nighttime and reducing misjudgments.

These and other aspects of the present disclosure will become apparent from the following description of the embodiment taken in conjunction with the following drawings and their captions, although variations and modifications therein may be affected without departing from the scope of the appended claims.

The present disclosure will become more fully understood from the following detailed description and accompanying drawings.

The present disclosure provides a preprocessing system for improving image recognition, and the preprocessing system is installed mainly on a vehicle for assisting recognition of objects in front of the vehicle when the vehicle is driven. Referring to <FIG>, a preprocessing system <NUM> provided in the present disclosure mainly includes an image sensor <NUM> and light-emitting diodes <NUM>. Basically, the image sensor <NUM> and the light-emitting diodes <NUM> may be installed at any location on a vehicle for facilitating recognition of the objects in front of the vehicle, and the light-emitting diodes <NUM> can be disposed to surround the image sensor <NUM>.

The image sensor <NUM> can be a common image sensing member as seen in a digital camera or a smartphone, and can include a light sensing element and a processor (not shown in figures). The light sensing element is an element that transforms optical images into electrical signals, and can be a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) active pixel sensor. The processor is a frame signal processing chip. After the light sensing element receives light, the light is transformed into the electrical signal and then is transmitted to the processor. The processor then performs calculation, such as performing automatic white balance adjustment and automatic exposure adjustment, and generates a digital image that can be finally stored into a storage media.

When the digital camera is used for taking photo, a lens of the digital camera is aimed at a target object. During photo taking, light emitted or reflected by the target object enters into the digital camera through the lens and is projected on the image sensor <NUM>, such that a digital image of the target object is generated. In other words, a light receiving region of the image sensor <NUM> is an image capture region A. As in the present disclosure, the image sensor <NUM> corresponds to the image capture region A (as shown in <FIG>).

Furthermore, in the present disclosure, a light-emitting diode (LED) is a white light LED that emits a white light source. More specifically, the white light LED used in the present disclosure is a white light LED having a color temperature of <NUM>. A color temperature is a color of light. The higher the color temperature is, the closer to white the color of light will be, while the lower the color temperature is, the closer to yellow the color of light will be.

Referring to <FIG>, a preprocessing method for improving image recognition is provided in the present disclosure, and includes steps as follows.

Step S <NUM>: referring to <FIG>, disposing three light-emitting diodes <NUM> at a left side, a right side, and a lower side of an image sensor <NUM>, respectively, in which the image sensor <NUM> corresponds to an image capture region A.

It should be noted that, the present disclosure is not limited to the above-mentioned example. The quantity and positions of the light-emitting diodes <NUM> surrounding the image sensor <NUM> can be adjusted according to actual requirements.

Step S2: referring to <FIG>, turning on the three light-emitting diodes <NUM>, such that each of the three light-emitting diodes <NUM> emits a white light source having a color temperature of <NUM>. Each of the white light sources has a fixed illumination area range <NUM>. An arrangement of the three light-emitting diodes <NUM> and the image sensor <NUM> allows the illumination area ranges <NUM> of the three white light sources to cover the image capture region A, and at least half of the whole image capture region A is covered thereby.

In the present embodiment, the three light-emitting diodes <NUM> are disposed at a left side, a right side, and a lower side of the image sensor <NUM>, respectively, such that the illumination area ranges <NUM> of the three white light sources cover at least lower half of the whole image capture region A.

Step S3: referring to <FIG>, turning off the three light-emitting diodes <NUM> for a time interval T, such that the image sensor <NUM> captures images to generate a preprocessing frame M under a low illuminance condition between <NUM> lux and <NUM> lux.

Step S4: repeatedly performing step S2 and step S3 to have the three light-emitting diodes <NUM> alternatingly turned on and turned off, such that the image sensor <NUM> generates a plurality of the preprocessing frames M for subsequent image recognition processing, as shown in <FIG>.

It should be noted that, the color temperature of the three white light sources is <NUM>. Therefore, an overlapping region AA of the illumination area ranges <NUM> of the three white light sources in the image capture region A has a color temperature closer to or equal to <NUM>. At this time, the image sensor <NUM> performs automatic white balance adjustment after receiving light, such that a frame predetermined to be captured also has a color temperature that is approximately or equal to <NUM>.

Under normal circumstances, the light-emitting diodes <NUM> are turned off. The light-emitting diodes <NUM> are only turned on during nighttime or under severe weather conditions when recognition of objects ahead of the vehicle is performed, and the image sensor <NUM> begins to capture frames of the objects. Furthermore, the image sensor <NUM> generally captures N frames in one second. As such, when the light-emitting diodes <NUM> are turned on and the image sensor <NUM> begins to capture frames, the time required for completing automatic white balance adjustment is generally under one second.

Moreover, by turning off the three light-emitting diodes <NUM> for the time interval T, the image sensor <NUM> is under a low illuminance condition that is between <NUM> lux and <NUM> lux. At the time of turning off the three light-emitting diodes <NUM>, an illuminance received by the image sensor <NUM> is also decreased. The illuminance represents a luminous flux received by a unit area, and is measured in units of lux. The main technical feature of the present disclosure is that the image sensor <NUM> performs image capture at a time when the illuminance of the image sensor <NUM> is at the lowest, as shown in <FIG> is a curve diagram of illuminance versus time when the image sensor <NUM> of the present disclosure receives light. When the light-emitting diodes <NUM> are turned off, the image sensor <NUM> stops receiving light. At the time the image sensor <NUM> stops receiving light, the illuminance of the image sensor <NUM> is decreased, and the image sensor <NUM> performs automatic exposure adjustment, such that the illuminance of the image sensor <NUM> returns to a balanced value. An area circled by broken lines in <FIG> represents the time when an illuminance L is at the lowest (approximately between <NUM> lux and <NUM> lux,), and a certain period of time has elapsed since turning off the light-emitting diodes <NUM>. The certain period of time is the time interval T that is approximately between <NUM> milliseconds and <NUM> milliseconds. Preferably, the illuminance of the image sensor <NUM> is decreased to <NUM> lux at <NUM> milliseconds after turning off the light-emitting diodes <NUM>. However, it should be noted that, the image sensor <NUM> is still white balanced to the color temperature of <NUM> at this time.

In other words, after turning on the light-emitting diodes <NUM> such that the image capture region A corresponding to the image sensor <NUM> is white balanced, the light-emitting diodes <NUM> is turned off immediately, such that the illuminance (luminous flux that is received) of the image sensor <NUM> is decreased to as low as <NUM> lux. In other words, the image sensor <NUM> is white balanced to (approximately or equal to) a color temperature of <NUM> and is under a condition of low illuminance. At this time, by having the image sensor <NUM> perform image capture on the target object in the image capture region A, the preprocessing frame M can be generated.

The embodiment of the present disclosure is mainly applied to recognize a target object in front of a vehicle that is driven under dim light (e.g., nighttime) or severe weather conditions (e.g., rain or fog). To a driver in the vehicle, the target object can be a pedestrian, other vehicles, etc. For example, when the driver drives the vehicle during nighttime, and turns on a headlamp for illuminating the front of the vehicle, the target object can be an oncoming driven vehicle having a headlamp turned on. At this time, the image sensor <NUM> is aimed at the light-emitting headlamps of the oncoming vehicle and performs image capture. Generally, when a newly manufactured vehicle is shipped from a factory, according to safety regulations, a color temperature of headlamps of the newly manufactured vehicle is maintained at <NUM>. Therefore, by using the preprocessing method for improving image recognition of the present disclosure, in the preprocessing frame M generated by the image sensor <NUM> performing image capture on the light-emitting headlamps of the oncoming vehicle, a brightness (due to the image sensor <NUM> being maintained to be white balanced at a color temperature of <NUM>) of the target object (i.e., the headlamp of the oncoming vehicle emitting a light having a color temperature of <NUM>) can be further enhanced, and the surrounding environment can be further darkened (due to the image sensor <NUM> performing image capture under the condition of the lowest illuminance).

In this embodiment, the arrangement of the three light-emitting diodes <NUM> and the image sensor <NUM> allows the illumination area ranges <NUM> of the white light sources to cover the image capture region A. In the present disclosure, the illumination area ranges <NUM> of the three white light sources at least cover one half of the whole image capture region A. That is to say, a distance between the light-emitting diodes <NUM> and the image sensor <NUM> affects a size of the overlapping region AA of the illumination area ranges <NUM> in the image capture region A. Specifically, a luminous intensity of light projected on the image sensor <NUM> by the light-emitting diodes <NUM> that are spaced apart from the image sensor <NUM> by a gap D is approximately equal to a luminous intensity of light projected on the image sensor <NUM> by an external light source at a predetermined distance from the image sensor <NUM>. The term "luminous intensity", also known in brief as "light intensity" or "luminosity", represents a physical measure of the wavelength-weighted power emitted by a light source in a particular direction per unit solid angle, and is measured in units of candela.

In the above-mentioned example, the light-emitting headlamp of the oncoming vehicle is the external light source. Since all oncoming vehicles approach the vehicle driven by the driver from an opposite direction, the predetermined distance is between <NUM> meters and <NUM> meters, and is preferably <NUM> meters. That is, when the oncoming vehicle is <NUM> meters from the vehicle of the driver, image recognition is required to be performed on the oncoming vehicle. Therefore, a luminous intensity of light projected on the image sensor <NUM> by the external light source at a predetermined distance of <NUM> meters from the image sensor <NUM> is equal to the luminous intensity of the light projected on the image sensor <NUM> by the light-emitting diodes <NUM> that are spaced apart from the image sensor <NUM> by the gap D. Therefore, the gap D can be adjusted with the luminous intensity being fixed, or the luminous intensity of the light projected on the image sensor <NUM> by the light-emitting diodes <NUM> can be adjusted with the gap D being fixed. In this embodiment, the gap D is adjusted to be between <NUM> millimeters and <NUM> millimeters.

In conclusion, by virtue of "disposing the three light-emitting diodes <NUM> at a left side, a right side, and a lower side of the image sensor <NUM>, respectively, in which the image sensor <NUM> corresponds to the image capture region A", "turning on the three light-emitting diodes <NUM>, such that each of the light-emitting diodes <NUM> emits at least one white light source having a color temperature of <NUM>, in which each of the white light sources has a fixed illumination area range <NUM>, and the illumination area ranges <NUM> of the three white light sources at least cover one half of the image capture region A, such that a color temperature of the covered half of the image capture region A is approximately or equal to <NUM>", "turning off the three light-emitting diodes <NUM> for a time interval T, such that the image sensor <NUM> captures images to generate a preprocessing frame M under a low illuminance condition between <NUM> lux and <NUM> lux", and "alternatingly turning on and off the three light-emitting diodes <NUM>, such that the image sensor <NUM> generates a plurality of the preprocessing frames M", the preprocessing method for improving image recognition provided in the present disclosure is capable of improving image recognition during nighttime and reducing misjudgments.

Another beneficial effect of the present disclosure is that, by virtue of "the image sensor <NUM> corresponding to the image capture region A", "the three light-emitting diodes <NUM> being disposed at a left side, a right side, and a lower side of the image sensor <NUM>, respectively, each of the light-emitting diodes <NUM> emitting at least one white light source having a color temperature of <NUM>, and each of the white light sources having a fixed illumination area range <NUM>", "the illumination area ranges <NUM> of the three white light sources at least covering one half of the image capture region A, such that a color temperature of the covered half of the image capture region A being approximately or equal to <NUM>", and "the image sensor <NUM> generating a preprocessing frame M under a low illuminance condition between <NUM> lux and <NUM> lux, and the low illuminance condition is generated by turning on and off the three light-emitting diodes <NUM> once", the preprocessing system for improving image recognition provided in the present disclosure is capable of improving image recognition during nighttime and reducing misjudgments.

Furthermore, in order to solve the issue in the current technology that an image captured during nighttime or under severe weather conditions is difficult to recognize, in the present disclosure, the white light LED that emit lights having a color temperature of <NUM> is configured to surround the image sensor <NUM> and is alternatingly turned on and turned off. In this way, before performing image capture, the image sensor <NUM> has a color temperature maintained at <NUM> after undergoing automatic white balance adjustment, and is maintained at a low illuminance after undergoing automatic exposure adjustment. As a result, in the obtained preprocessing frame M, a brightness of the target object is further enhanced, and the surrounding environment is further darkened, which are advantageous for further performing image recognition process.

Claim 1:
A preprocessing method for improving image recognition, of a target object in front of a driver's vehicle under dim light or severe weather conditions using a preprocessing system including an image sensor (<NUM>) with white balance and at least one light emitting diode (<NUM>),
the preprocessing method comprising:
disposing the at least one light-emitting diode (<NUM>) to surround the image sensor (<NUM>), the image sensor (<NUM>) having an image capture region (A);
turning on the at least one light-emitting diode (<NUM>), such that the at least one light-emitting diode (<NUM>) emits at least one white light having a color temperature of <NUM>, with a fixed illumination area range (<NUM>), and the illumination area range (<NUM>) covers the image capture region (A), so that a color temperature of the image capture region (A) is approximately or equal to <NUM>;
turning off the at least one light-emitting diode (<NUM>) for a time interval, such that the image sensor (<NUM>) captures images to generate a preprocessing frame (M) under a low illuminance condition that is between <NUM> lux and <NUM> lux; and
alternatingly turning on and off the light-emitting diode (<NUM>), such that the image sensor (<NUM>) generates a plurality of the preprocessing frames (M).