KR20160135691A - Method for controlling flash timing of extension flash module - Google Patents

Abstract

The present invention relates to a method for controlling flash timing of an extension flash module in cooperation with a mobile device. Provided is the method comprising the steps of: detecting a specific event, wherein a time period from time at which the specific event occurs to time at which exposure of a first row of a photo sensor starts is a constant; determining whether a single flashable time period for which one flash is receivable by every row of the photo sensor is present; performing a single flash after a delay time from the time at which the specific event has occurred when the single flashable time period is present; and, when the single flashable time period is absent, performing a first flash after a delay time from the time at which the specific event has occurred, and performing a second flash after a delay time from time at which the first flash has been performed.

Description

METHOD FOR CONTROLLING FLASH TIMING OF EXTENSION FLASH MODULE [0002]

Cross-reference

The present invention claims priority to TW 103140180, filed on November 19, 2014, TW 104107362, filed March 9, 2015, and TW 104119387, filed June 16, 2015. The present invention is a continuation-in-part application of US 14/643905, filed March 10, 2015.

Technical field

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to the technology of flash lamps, and more particularly to a method for controlling the flash timing of an extension flash module of a mobile device.

With the ever-improving pixel and quality of digital pictures, mobile devices, such as mobile phones and tablets, have become a trend to have the ability to take pictures. However, these built-in digital cameras can not be performed as well as conventional digital cameras in the case of low lighting or backlighting.

Some built-in digital cameras also have a light-emitting diode (LED) supplemental lamp, but due to battery capacity of the mobile device and heat dissipation problems of the LED, the auxiliary light provided by the LED- light is severely limited. If the distance between the photographed object and the LED sub-lamp exceeds 1 meter, the LED sub-light can not provide a suitable light source to adequately expose the pixels of the photo sensor.

A Xenon high-intensity discharge (HID) lamp can provide many auxiliary lights within a short period of time. Thus, conventional digital cameras typically have xenon HID. The more charge on a xenon HID, the more the low-voltage battery power supply can be converted to a high-voltage power supply and stored in a high-capacitance high-voltage capacitor. Xenon HID operates according to a mechanical shutter and can properly expose the pixels of the optical sensor under low light or backlight conditions by being triggered at the appropriate timing to convert the electricity stored in the high voltage capacitor into a high brightness auxiliary light in a very short period of time . Xenon HID requires high voltage capacitors with capacitances of tens to hundreds of microns and capable of withstanding 300-400 volts. In pursuit of lighter, thinner, and more compact mobile devices, a very large volume of these high voltage capacitors can not meet the requirements of current mobile devices. Thus, in order not to increase the volume and weight of existing mobile devices, the extended HID flash module is a viable and even an essential option.

Depending on the specifications of the capacitance in the high-voltage capacitors and the HID lamp tube, the flash time of the HID flash module lasts from tens to hundreds of microseconds (μs). Flashing at the right timing to evenly expose all the pixels in the optical sensor is an important issue to be addressed so that the extended HID flash module becomes a viable option. A mobile device with a photo-taking device typically employs a complementary metal-oxide-semiconductor (CMOS) optical sensor and a rolling shutter instead of a mechanical shutter as shown in FIG. 1 is a schematic view of a rolling shutter in the prior art; In Figure 1, all lines represent the time at which a row in the photosensor performs a light-sensing operation. There is a delay between the time that the photosensor row begins or ends exposing and the time that the preceding photosensor row begins or ends exposing, even though all of the photosensor rows in the frame have the same exposed length. During this delay time, the photographic device reads the exposure data in the photosensor row and resets the pixels to prepare for exposure in the next frame. Since the pictures are taken in different environments and therefore the devices for taking pictures are also set differently, the exposure time of one photosensor row is in a wide range and lasts from a few milliseconds to several hundreds of milliseconds.

However, according to the rolling shutter, the extended HID flash module can not usually find the optimal flash timing and thus can not improve the quality of the photograph.

In one aspect, the present invention provides a method of controlling flash timing of an extended flash module that cooperates with a mobile device and provides auxiliary light when a mobile device with an image retrieval device takes a picture, the image retrieval device comprising: Wherein N is a positive integer, the method comprising the steps of: detecting a specific event, wherein the method comprises: detecting the first row of the image retrieval device from the time when the particular event occurred, Wherein the time period up to the start of the time period is a constant; Determining whether a single flash has one single flashable time period receivable by all rows of the image retrieval device; Performing a single flash after a delay time from the particular event when a flash has a single flashable time period receivable by all rows of the image retrieval device; And performing a first flash after a delay time from the specific event if the single flashable time period is not present, and performing a second flash after the delay time from the first flash.

In one embodiment, the step of determining whether the one flash has one single flashable time period receivable by all rows of the image retrieval device comprises: detecting an intensity of ambient light; Comparing the intensity of the ambient light with a predetermined threshold value; Determining that there is one single flashable time period in which one flash is receivable by all the rows of the image retrieval device when the intensity of the ambient light is below the predetermined threshold; And determining that there is no single flashable time period in which one flash is receivable by all rows of the image retrieval device if the intensity of the ambient light exceeds the predetermined threshold.

In one embodiment, the method further comprises storing the different predetermined thresholds corresponding to different types of mobile devices in a storage device in the extended flash module, or storing different predetermined thresholds corresponding to different types of mobile devices And setting the mobile device to an application program that controls the extended flash module.

In one embodiment, the method further comprises performing a third flash after the delay time from the second flash.

In one embodiment, the step of determining whether the one flash has one single flashable time period receivable by all rows of the image retrieval device comprises: detecting an intensity of ambient light; Comparing the intensity of the ambient light with a first predetermined threshold and a second predetermined threshold; Determining that there is one single flashable time period in which one flash is receivable by all the rows of the image retrieval device if the intensity of the ambient light is below the first predetermined threshold; Determining that two flashes are required if the intensity of the ambient light exceeds the first predetermined threshold and is less than the second predetermined threshold; And determining that three or more flashes are required if the intensity of the ambient light exceeds the second predetermined threshold value.

In one embodiment, the method further comprises storing the different predetermined thresholds corresponding to different types of mobile devices in a storage device in the extended flash module, or storing different predetermined thresholds corresponding to different types of mobile devices And setting the mobile device to an application program that controls the extended flash module.

In one embodiment, the first flash is receivable by P rows of the image retrieval device and the second flash is receivable by Q rows of the image retrieval device, ≪ N, performing a third flash after the delay time from the second flash, wherein P and Q are positive integers.

In one embodiment, the first row has a common flashable period of time in any row before the a-th row and the a-th row, but may include a flashable time in any row after the b-th row and the b- While the Nth row has a common flushable time period in any row after the cth row and the cth row but is not flushable to any row before the dth row and the dth row Performing a first flash after a delay time from the specific event without having a time period and performing a second flash after a delay time from the first flash further comprises: Performing the first flash within an exposure time period of an Xth row; And performing the second flash after the Nth row has begun to expose and within an exposure time period of the Yth row; d? x? a and c? Y? b, and a, b, c, d, X and Y are positive integers.

In one embodiment, the step of determining whether the one flash has one single flashable time period receivable by all the rows of the image retrieval device comprises performing a photo exposure test exposure procedure, Wherein the exposure of the light source is performed according to ambient light; Comparing the luminance of the pixel with a reference value to determine whether there is a row having a luminance lower than the reference value; Determining that there is one single flashable time period in which one flash is receivable by all rows of the image retrieval device if there is no row with less than the reference value; And determining that there is no single flashable time period in which one flash is receivable by all rows of the image retrieval device if there is a row with a luminance below the reference value.

In one embodiment, the method further comprises: determining a number (P) of rows of pixels having a luminance that exceeds the reference value; And comparing said number (P) to the total number of said rows (N) to determine the number of flashes required for all rows to receive at least one flash; P and N are positive integers.

In another aspect, the present invention provides a method of controlling flash timing of an extended flash module that cooperates with a mobile device and provides an auxiliary light when a mobile device with an image retrieval device takes a picture, the image retrieval device comprising N Wherein N is a Portage Boolean integer, the method further comprising: controlling timing of a first flash of the extended flash module; And performing a second flash or more flashes after the delay time from the first flashes; Wherein all the flashes are combined to expose all of the rows so that the exposed pixels combine to form the entire photograph.

BRIEF DESCRIPTION OF THE DRAWINGS The objectives, technical details, attributes or parameters of the present invention, and the effects thereof, will be better understood with reference to the following detailed description of the embodiments with reference to the accompanying drawings.

1 is a schematic diagram illustrating a manner in which a rolling shutter operates in accordance with the prior art;
2 is a schematic diagram illustrating a flashable time period in accordance with one embodiment of the present invention;
3 is a flow chart of a method of photographing according to a preferred embodiment of the present invention.
Figure 4 illustrates an oscillogram of a signal from an embedded LED sub-lamp of a mobile device employing a method of taking a picture according to a preferred embodiment of the present invention.
5 is a system block diagram of an extended flash module according to a preferred embodiment of the present invention.
6 shows an example of requesting two or more flashes;
Figure 7 illustrates a method according to a preferred embodiment of the present invention.
Figure 8 shows another example of requiring two or more flashes.
9 illustrates another method according to a preferred embodiment of the present invention.
10 is a diagram illustrating a hardware embodiment according to a preferred embodiment of the present invention.
9 illustrates another method according to a preferred embodiment of the present invention.

The invention may be more fully understood from the following detailed description. The drawings referred to throughout the description of the present invention are for illustration purposes only and are not drawn to scale.

In accordance with the present invention, an extended flash module, such as an HID flash module, cooperates with the mobile device and provides auxiliary light when the mobile device takes a picture. The mobile device comprises an image retrieval device, such as an optical sensor, and the image retrieval device comprises pixels arranged in rows. 2 is a schematic diagram illustrating a flashable time period in accordance with one embodiment of the present invention. Referring to FIG. 2, the flashable time period is between t1 and t2 (and includes t1 and t2) since flash light within this time period can be received by all photosensor rows; That is, any time point within this flashable time period is a flashable time. If the flash timing is earlier than t1, subsequent photosensor rows are not exposed. If the flash timing is later than t2, the previous row of photosensors is not exposed. However, since the mobile device can perform multiple-tasks and perform other tasks at the same time, these other tasks can affect the execution timing of the flash control; As a result, the delay time between the time the user presses the shutter and the actual flash timing becomes unclear, which means that the time from when the user pressed the shutter to t1 or t2 is not fixed. Conventionally, there is no viable and reliable method of ensuring that the flash timing of the extended flash module is stably controlled between t1 and t2, and flashing at an incorrect timing can seriously and seriously impair the functionality of the extended HID flash module . However, the present invention solves this problem. A method of taking a picture in which the flash timing of the extended flash module can be stably controlled between t1 and t2 is provided by the present invention as shown in Fig. 2 and described below.

Figure 3 shows a flow chart of a method of photographing according to a preferred embodiment of the present invention. The extended HID flash module is used by the mobile device to assist the light when taking pictures. The method includes the following steps:

Step S300: Start.

Step S301: The specific event is detected before the flash enable time. 2, in one embodiment, an image retrieval device included in a mobile device includes a rolling shutter mechanism in which an optical sensor row of an image retrieval device is sequentially exposed row by row, and exposure of a photosensor row is processed in an integral form It adopts. As shown in FIG. 2, the flashable time of a particular frame retrieved is between t1 and t2 (and includes t1 and t2). Referring to FIG. 2, t1 and t2 are the times at which the last row begins to expose (integration starts) and the time at which the first row ends exposure (integration ends). If the flash module flashes during a period between t1 and t2 (flashable time period), all rows can receive flash light during that exposure.

After the mobile device confirms that the user has provided a shutter command by pressing the shutter, the mobile device performs a preparatory operation, such as performing photometry and focusing, The exposure time can be determined. The flashable time period t1 to t2 of the extended flash module is known at a specific moment and after this particular moment, that is, a certain event that occurs at this specific moment (referred to herein as "specific event & So that it is no longer affected by any other task the mobile device can perform. Based on this, for example, the designer can determine the time of a particular frame by designing a particular application program or use a signal from a particular hardware to determine the time of a particular frame. That is, when a particular event occurs, the time period from when a particular event occurs to when it is flashable is a fixed, relatively stable, and known period. There is a fixed length of time between the occurrence of a particular event and the time available for flashing. (The flashable time may be any designated time point within the flashable time period.) Thus, in one aspect, the present invention employs the time of a particular event as a basis for prediction.

In one embodiment, predicting the flashable time and controlling the flash may be implemented by a mobile device application program (e.g., a mobile phone application program), e.g., a mobile phone application program Lt; RTI ID = 0.0 > a < / RTI > first optical sensor row (at a particular frame) In this example, the fixed time length is the period from the time when the first photosensor row begins to expose to the time when the last photosensor row begins to expose. As another example, a particular event may be the time at which the Kth light sensor row begins to expose (in a particular frame that it is desired to be searched for). In this example, the fixed time length is the period from the time the Kth light sensor row begins to expose to the time the last light sensor row begins to expose. As another example, a particular event may be the time at which the Kth light sensor row in the previous Mth frame starts to expose. In this example, the fixed time length is the sum of M frame times in the period from the time the Kth light sensor row begins to expose to the time the last light sensor row begins to expose. As another example, a particular event may be the time at which the Kth light sensor row in the previous Mth frame ends the exposure. If the Kth optical sensor row terminates the exposure earlier than the time that the last optical sensor row begins to expose, in this example, the fixed time length is the time from the time the Kth optical sensor row ends the exposure to the last optical sensor row Plus the M frame times up to the time it starts to expose. If the Kth optical sensor row terminates the exposure later than the time the last optical sensor row begins to expose, in this example, the fixed time length is the time from the time the Kth optical sensor row ends the exposure to the last optical sensor row 1 < / RTI > frame times in the period up to the start of the exposure. In this example, the fixed time length corresponding to the period from the specific event to the flashable time is calculated for the last time point t2 of the flashable time period. However, equally, a fixed time length can be calculated for any time point between t1 and t2 (and including t1 and t2). In the above description, K and M are positive integers.

In another embodiment, predicting the flash time and controlling the flash may be implemented with reference to a hardware signal. For example, a particular event may be a signal from the mobile device's embedded LED sub-lamp. Figure 4 illustrates an oscillogram of a signal from an embedded LED sub-lamp of a mobile device employing a method of taking a picture according to a preferred embodiment of the present invention. Referring to FIG. 4, when the mobile device takes a picture, the built-in LED sub-lamp lights up for a first time to indicate that the lens is focusing and illuminates for a second time period, ). In this example, in step S301 of the present invention, the specific event may be an event in which the LED sub-lamp illuminates for a first time or a second time.

Step S302: Triggering the flash command flashing during the flashable time period according to the duration from the flash delay time and the flash enable time to the extended flash module. In the context of the present description, "triggering a flash instruction" means that the extended flash module begins to execute a flash instruction that it has received or received. As far as the extended flash module is concerned, there is a flash delay time td between the time at which the extended flash module starts executing the flash command and the time at which the actual flash of the extended flash module occurs. Thus, in addition to the time from a particular event to the time available for flashing, the delay time of the extended flash module itself, flash control should be considered. That is, since the aforementioned period from a particular event to a flashable time is a constant and the delay time of the extended flash module is a known value, the method of this embodiment can determine when to trigger a flash command according to these constants and known values. For example, if the delay time from the time that the flash command is received by the extended flash module to the time when the actual flash of the extended flash module occurs is td (where td is calculated for the time the flash command was received) Should be between (t1-td) and (t2-td). Otherwise, if the reference initial time point of the delay time td is the time at which a specific event occurs (the delay time td starts counting at the time when a specific event occurs) and the time at which a specific event occurs is t0 , The flash timing needs to satisfy the following relationship: (t1-t0) <td <(t2-t0). The extended flash module flashes at the end of the delay time (td). When the delay time td is calculated for a particular time point having a time difference from the time when the specific event occurs, the delay time td is calculated according to the definition of the delay time td ) This time difference can be considered.

This embodiment controls the flash timing with the internal software of the mobile device when the extended flash module is connected to the mobile device by hardware (e.g., via a universal serial bus (USB) or headset socket) And the like. In another embodiment consistent with the teachings of the present invention, the extended flash module may also be optically coupled to control the flash timing. 5 shows a system block diagram of an extended flash module employing a method according to an embodiment of the present invention. 5, the extended flash module 50 can be, for example, an extended flash module that is not electrically connected to the mobile device 51, or even a non-contact module separate from the mobile device 51 . The extended flash module 50 includes an optical sensor circuit 501, a delay circuit 502, a flash lamp driving circuit 503, and an HID lamp 504. [ When the LED in the mobile device 51 is illuminated, this event is detected as a specific event by the optical sensor circuit 501 and triggers the HID lamp 504 to flash for a flashable time (t1 to t2). In general, the LED in the mobile device 51 illuminates 2 times (the first is for focus and the second is for flash), and a particular event can be defined as one of these two lights.

Optical coupling is only one of many possible ways of implementing the present invention; Having the benefit of the teachings of the present disclosure, those of ordinary skill in the art will recognize that the present invention can be implemented wirelessly, for example, via Wi-Fi, near field communication (NFC), or Bluetooth Or by detecting the voice generated by the shutter of the mobile device. &Lt; RTI ID = 0.0 &gt; [0031] &lt; / RTI &gt; The present invention is not limited to the embodiments described herein.

The above description describes a "fixed time length" which is a relatively stable and known time period from when a particular event occurs to when it is flashable. However, there may still be minor variations or errors caused by unknown sources; Even the designer does not guarantee that the "fixed time length" absolutely does not include any minor variations. Nonetheless, as far as practical applications are concerned, excellent flash control can still be achieved as long as these variations are within an acceptable range. For example, if the error in calculating the "fixed time length" is less than half of the flashable time period, then such error is acceptable and is still understood to be within the scope defined by the present invention.

6, which is compared with FIG. In most cases, there is one flashable time period where one flash can be received by every row of the image retrieval device. However, in certain cases, for example, when the ambient light is too strong or a photo is taken against strong light, so that when all the photosensor row exposure times are short, one flash is received by all rows of the image search device There may not be one possible flash-time period. In the given example shown in FIG. 6, the (N-3) th row is a row in which the first row starts to be exposed after the exposure ends and the first row is the (N-3) It may not have a common flashable time period in any row after the row. Likewise, the second row may not have a common flashable time period in the (N-2) th row and any row after this (N-2) th row.

According to the present invention, a method for controlling flash timing of an extended flash module preferably further comprises determining whether one flash has one single flashable time period receivable by all rows of the image retrieval device do. If one flash does not have one single flashable time period receivable by every row of the image retrieval device, then two or more flashes are performed. In the case of Figure 6, the extended flash module 50 can detect and discover that one flash is not enough for all rows of the image retrieval device to receive at least one flash, in which case two or more flashes .

More specifically, reference is made to Fig. In this embodiment, first, the intensity of ambient light is detected (step S701) and compared with a predetermined threshold value (step S702). "Ambient light" is preferably light directed opposite the direction in which the image retrieving device is directed to determine the requirement of the number of flashes. If the intensity of the ambient light is below a predetermined threshold, then it can be found that the exposure time of each photosensor row is sufficiently long so that a common flashtable time period covers all photosensor rows, and only one flash is required S703). If the intensity of ambient light exceeds a predetermined threshold, it is found that the exposure time of each photosensor row is too short so that a common flashable time period is not found to cover all photosensor rows, so that after the first flash, (Step S704).

6, the first row has a common flashable time period in any row before the (N-4) th row and the (N-4) th row, Th row and any row after this (N-3) th row may not have a common flashable time period. The Nth row has a common flashable time period in any row after the 5th row and the 5th row (not shown), but a common flashable time period is set for any row before the 4th row and this 4th row You can not have it. Thus, two flashes can be performed at two different timings, where the first flash is performed before the time that the first row ends the exposure and is within the exposure time period of the Xth row, and the second flash is performed at the Nth row Is performed after the expiration of this exposure and within the exposure time period of the Y-th row. In the example shown in FIG. 6, 4? X? N-4 and 5? Y? N-3, i.e., the first flash must be within the exposure time period of the first row (X? N-4) Flash should be able to expose the last row before the time when the Nth row (4 X) starts to expose, while the second flash should be within the exposure time period of the Nth row (5 Y) Flash must be able to expose the first row (Y # N-3) after the time when the first row ends the exposure.

In the worst case, the two flashes may not be enough for all rows of the image retrieval device to receive at least one flash, and perhaps three or more flashes are required, as in the example shown in FIG.

In this case, referring to Fig. 9, in this embodiment, first, the intensity of the ambient light is detected (step S801) and compared with the first predetermined threshold value (step S802). If the intensity of ambient light is below a first predetermined threshold, this means that only one flash is required for all photosensor rows to receive the flash (step S803). If the intensity of ambient light exceeds a first predetermined threshold, the intensity of ambient light is compared with a second predetermined threshold (step S804). If the intensity of the ambient light exceeds the first predetermined threshold but is below the second predetermined threshold, this means that the two flashes are sufficient for all the rows to receive at least one flash (step S805). If the intensity of ambient light exceeds a second predetermined threshold, this means that two flashes are not sufficient for all rows to receive at least one flash, so three flashes are required (step S806). In the above description, the second predetermined threshold value exceeds the first predetermined threshold value.

Likewise, whether four or more flashes are required can be determined by setting a corresponding threshold value according to the above logic.

When performing two or more flashes, it is possible for a particular photosensor row to be exposed more than once. For example, the first flash may cover the first row through the jth row, while the second flash may cover the (jn) th row through the Kth row (where j, k and n are positive Integer, and n < j < k). This is acceptable. Further, when two or more flashes are performed, these flashes do not necessarily have to be in the same frame. For example, a first flash may be performed in a previous frame to cover a portion of the photosensor row and a second flash may be performed in a subsequent frame to cover another portion of the photosensor row, The combined photosensor rows combine to form one entire picture.

See FIGS. 6 and 8. FIG. It can thus be determined whether the two flashes are sufficient to cover all photosensor rows. The first flash should be performed before the first row ends the exposure, while the second flash should be performed after the Nth (last) row has begun to expose. The first flash can cover a maximum of P rows (i.e., the last row that started exposure before the first row finishes exposing is the Pth row), and the second flash covers up to Q rows (I.e., after the Nth row starts to expose, the first row ending the exposure is the (NQ-1) th row), then P + Q < Where P, Q and N are positive integers and P < N and Q < N. In the example shown in FIG. 8, P = 4 and Q = 4 (if all optical sensor rows require the same exposure time period, generally P = Q), and if N> 8, Two flashes are not enough to receive one flash and at least three flashes are required. Whether three flashes are sufficient to cover all photosensor rows can be similarly determined: the first flash can cover a maximum of P rows, the second flash can cover a maximum of Q rows, Assuming that the third flash can cover a maximum of R rows, when P + Q + R < N, this means that at least four flashes are required, where P, Q, R and N are positive integers P < N, Q < N and R < N.

The exposure time period of the optical sensor row varies with the intensity of the ambient light, and the amount of change may vary from one manufacturer's mobile device to another manufacturer's other mobile device. However, in order to achieve a common goal of optimizing photo-taking performance, different mobile devices of different manufacturers have similar variations. Thus, according to the present invention, even if the extended flash module 50 is an external component of the mobile device, the predetermined threshold value (or the first and second predetermined thresholds) described above can be preset, For example, in an extended flash module 50 in the mobile device or in an application program to control the extended flash module 50. [

In another embodiment, the extended flash module 50 may obtain relevant information from the mobile device to obtain more precise parameters for the mobile device of different manufacturers. 10, different predetermined thresholds (or first and second predetermined thresholds) corresponding to different manufacturers' mobile devices may be stored in the storage device of the extended flash module 50 (e.g., Memory 505). &Lt; / RTI &gt; To take a picture, the processor 506 in the extended flash module 50 communicates with the mobile device and obtains the model type or attribute of the mobile device, and obtains a corresponding predetermined threshold value (or the first and second A predetermined threshold) to determine the number of flashes required.

It has been described above that it is required to obtain information on the ambient light by "comparing the intensity of the ambient light with a predetermined threshold value ". The extended flash module 50 may acquire such information from the mobile device or may install the ambient light sensor in the extended flash module 50 to obtain such information.

In another embodiment, referring to FIG. 11, when a predetermined threshold (or first and second predetermined thresholds) corresponding to some types of mobile devices is not known, the number of flashes is determined through a check process . In this embodiment, first, for example, a mobile device may have an extended flash module and take a photo-taking test procedure (step S901) when it is ready to take a first picture or at any other appropriate moment. In this photo-taking test procedure, the image retrieval device (e.g., photo sensor) in the mobile device exposes the frame, and the extended flash module flashes according to the ambient light at the moment of photo-taking (step S902). Next, the exposed frame is checked by comparing the luminance of the pixel with the reference threshold value (step S903) and determining whether there is a row having luminance lower than the reference threshold value (step S904). If there is no row having a luminance lower than the reference threshold value, it is determined that only one flash is sufficient (step S905). When there is one row with a luminance lower than the reference threshold value, the number P of rows having a luminance exceeding the reference threshold value is obtained and compared with the total number of rows N (steps S906 and S907). 1 < (N / P) < 2, the flash time is 2; 2 < (N / P) < 3, the flash time is 3, and so on. In this way, an optimal number of flash times can be obtained (step S908).

In view of the above, the idea of the present invention is to use a specific event as a reference time point; The time at which a specific event occurs is relatively fixed and known relative to the time available for flashing. On the other hand, the delay time of the flash module is further considered so that the extended flash module is triggered at the proper timing to flash for a flashable time period. Furthermore, if one flash is not sufficient to cover all the photosensor rows, multiple flashes may be performed. Thus, according to the method of taking a picture provided by the present invention, the quality of the picture taken by the mobile device is improved by the pixel being properly exposed under a low illumination or backlight environment.

In another embodiment, the first flash of a plurality of flashes may not be performed by counting the delay time from the specific events described above, but may be the initial flash time arbitrarily determined by the extended flash module or mobile device. After this first flash, while taking one and the same picture, a second flash or more flashes may be performed in accordance with the present invention. For example, an initial flash may be arbitrarily determined by an extended flash module or a mobile device, but it may be determined whether this initial flash can cover all photosensor rows and, if not, one or more flashes Can be determined according to the principle described above. As another example, even though a single flash is sufficient for all the photosensor rows to receive the flash, multiple flashes can be performed when the time with good flash timing is not clear.

While certain exemplary embodiments have been shown and described in the accompanying drawings, it is to be understood that such embodiments are for illustrative purposes only, and are not intended to limit the broad scope of the present invention, It is to be understood that other variations may occur and are not intended to be limited to the specific configurations and arrangements shown and described. For example, in a method embodiment, the sequences of specific steps may be interchanged, or these steps may be performed in parallel (e.g., steps S802 and S804). It is, therefore, obvious that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (11)

CLAIMS What is claimed is: 1. A method of controlling flash timing of an extended flash module that cooperates with a mobile device and provides a secondary light when a mobile device with an image retrieval device captures a picture, the image retrieval device comprising pixels arranged in N rows , N is a positive integer,
Detecting a specific event, the time period from the time when the specific event occurred to the start of exposure of the first row of the image retrieval device is a constant;
Determining whether a single flash has a single flashable time period receivable by all rows of the image retrieval device;
When there is a single flashable time period in which one flash can be received by all the rows of the image search device, the extended flash module acquires the occurrence information of the specific event; And
Wherein the extended flash module triggers a flash instruction after a delay time from the particular event to perform a single flash, the flash timing of the extended flash module is within a single flashable time,
If the single flashable time period does not exist, the extended flash module acquires the occurrence information of the specific event; / RTI &gt;
The extended flash module may be configured to control a first flash time after a delay time and trigger a flash command to perform a second flash after a delay time from a first flash, &Lt; / RTI &gt; 2. The method of claim 1, wherein determining whether the one flash has one single flashable time period receivable by all rows of the image retrieval device comprises:
Detecting an intensity of ambient light;
Comparing the intensity of the ambient light with a predetermined threshold value;
Determining that there is one single flashable time period in which one flash is receivable by all the rows of the image retrieval device when the intensity of the ambient light is below the predetermined threshold; And
Determining that there is no single flashable time period in which one flash is receivable by all rows of the image retrieval device if the intensity of the ambient light exceeds the predetermined threshold. 3. The method of claim 2, further comprising: storing a different predetermined threshold value corresponding to a different type of mobile device in a storage device in the extended flash module, or storing different predetermined thresholds corresponding to different types of mobile devices in the mobile device To an application program that controls the extended flash module. 2. The method of claim 1, further comprising: performing a third flash after a delay time from the second flash. 2. The method of claim 1, wherein determining whether the one flash has one single flashable time period receivable by all rows of the image retrieval device comprises:
Detecting an intensity of ambient light;
Comparing the intensity of the ambient light with a first predetermined threshold and a second predetermined threshold;
Determining that there is one single flashable time period in which one flash is receivable by all the rows of the image retrieval device if the intensity of the ambient light is below the first predetermined threshold;
Determining that two flashes are required if the intensity of the ambient light exceeds the first predetermined threshold and is less than the second predetermined threshold; And
And determining that three or more flashes are required if the intensity of the ambient light exceeds the second predetermined threshold value. 6. The method of claim 5, further comprising: storing a different predetermined threshold value corresponding to a different type of mobile device in a storage device in the extended flash module; or storing a different predetermined threshold value corresponding to a different type of mobile device in the mobile device To an application program that controls the extended flash module. 2. The method of claim 1 wherein the first flash is receivable by P rows of the image retrieval device and the second flash is receivable by Q rows of the image retrieval device, Further comprising performing a third flash after a delay time from the second flash when Q < N, wherein P and Q are positive integers. 3. The method of claim 1, wherein the first row has a common flashable time period in any row before the a-th row and the a-th row, but is capable of being flashed into any row after the b- While the Nth row has a common flashable time period in any row after the cth row and the cth row, but the random number row before the dth row and the dth row has no time period, Performing a first flash after a delay time from the specific event without having a possible time period, and performing a second flash after a delay time from the first flash,
Performing the first flash before the first row terminates the exposure and within an exposure time period of the Xth row; And
Performing the second flash after the Nth row has begun to expose and within an exposure time period of the Yth row;
d? x? a and c? Y? b, and a, b, c, d, X and Y are positive integers. 2. The method of claim 1, wherein determining whether the one flash has one single flashable time period receivable by all rows of the image retrieval device comprises:
Performing a photo-taking test exposure procedure, wherein the exposure of the pixel is in accordance with ambient light;
Comparing the luminance of the pixel with a reference value to determine whether there is a row having a luminance lower than the reference value;
Determining that there is one single flashable time period in which one flash is receivable by all rows of the image retrieval device if there is no row with less than the reference value; And
Determining that there is no single flashable time period in which one flash is receivable by all rows of the image retrieval device if there is a row with a luminance below the reference value. 10. The method of claim 9,
Determining a number of rows (P) of pixels having a luminance that exceeds the reference value; And
Comparing said number (P) to the total number of said rows (N) to determine the number of flashes required for all rows to receive at least one flash;
P and N are positive integers. CLAIMS What is claimed is: 1. A method of controlling flash timing of an extended flash module that cooperates with a mobile device and provides a secondary light when a mobile device with an image retrieval device captures a picture, the image retrieval device comprising pixels arranged in N rows , N is a Portage constant,
Controlling the timing of the first flash of the extended flash module; And
Performing a second flash or more flashes after the delay time from the first flash;
Wherein all the flashes are combined to expose all of the rows so that the exposed pixels combine to form the entire photograph.

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