(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2007/0280660 A1
`(43) Pub. Date:
`Dec. 6, 2007
`Yeh et al.
`
`US 20070280660A1
`
`(54) METHOD FOR FIRING FLASH OF
`IMAGE-CAPTURING DEVICE
`
`(75) Inventors:
`
`Jeff Yeh, Taipei (TW); Brian Fan,
`Taipei (TW)
`Correspondence Address:
`TROXELL LAW OFFICE PLLC
`SUITE 1404, 5205 LEESBURG PIKE
`FALLS CHURCH, VA 22041
`(73) Assignee:
`Premier Image Technology Corp.
`
`(21) Appl. No.:
`
`11/583,950
`
`(22) Filed:
`(30)
`
`Oct. 20, 2006
`Foreign Application Priority Data
`
`May 30, 2006 (TW) ................................. O951 19098
`
`Publication Classification
`
`(51) Int. Cl.
`GO3B I5/03
`(2006.01)
`(52) U.S. Cl. .......................................... 396/61; 396/164
`
`ABSTRACT
`(57)
`A method for firing a flash of an image-capturing device is
`disclosed. The method uses a focus parameter, which is
`generated during the focusing procedure of the image
`capturing device, to estimate a shooting distance. Then, the
`method dynamically determines a flash intensity of the flash
`according to the shooting distance, thereby obtaining
`improved exposure effect. In addition, since the preflash of
`the flash is skipped, the method can reduce the power
`consumption and shorten the shooting time, thereby enhanc
`ing the performance of the image-capturing device and the
`flash.
`
`Performing a focusing procedure for the image-capturing
`device to generate a focusing parameter
`
`Estimating a shooting distance according to the
`focusing para?ieter
`
`Determining a flash intensity according to the
`shooting distance
`
`
`
`
`
`
`
`
`
`Firing the flash according to the flash
`intensity when the image-capturing device captures an
`image
`
`2
`
`13
`
`14
`
`5
`
`Qualcomm, Exh. 2016, p. 1
`Apple v. Qualcomm, 2018-01278
`
`

`

`Patent Application Publication
`
`Dec. 6, 2007 Sheet 1 of 5
`
`US 2007/0280660 A1
`
`Performing a focusing procedure for the image-capturing
`device to generate a focusing parameter
`
`Estinating a shooting distance according to the
`.
`focusing parameter
`
`Determining a flash intensity according to the
`shooting distance
`
`
`
`
`
`Firing the flash according to the flash
`intensity when the image-capturing device captures an
`image
`
`
`
`2
`
`13
`
`14
`
`15
`
`F I. G. 1
`
`Qualcomm, Exh. 2016, p. 2
`Apple v. Qualcomm, 2018-01278
`
`

`

`Patent Application Publication
`
`Dec. 6, 2007 Sheet 2 of 5
`
`US 2007/0280660 A1
`
`Performing a focusing procedure for the image-capturing
`device to generate an optimurn focus step nuFaber
`
`Estimating a shooting distance according to the optimum
`focus step number
`
`Deterinining a flash intensity according to the shooting
`distance
`
`Firing the flash according to the flash intensity
`when the image-capturing device captures an image
`
`22
`
`23
`
`24
`
`2 5
`
`F I G. 2
`
`Qualcomm, Exh. 2016, p. 3
`Apple v. Qualcomm, 2018-01278
`
`

`

`Patent Application Publication
`
`Dec. 6, 2007 Sheet 3 of 5
`
`US 2007/0280660 A1
`
`Perfortning a focusing procedure for the image-capturing
`device to generate a focusing parameter
`
`Estimating a shooting distance according to the focusing
`parameter
`
`Determining a flash intensity according to the shooting
`distance and a zoom step of the image-capturing device
`
`Firing the flash according to the flash intensity
`when the image-capturing device captures an image
`
`32
`
`33
`
`34
`
`35
`
`F I. G. 3
`
`Qualcomm, Exh. 2016, p. 4
`Apple v. Qualcomm, 2018-01278
`
`

`

`Patent Application Publication
`
`Dec. 6, 2007 Sheet 4 of 5
`
`US 2007/0280660 A1
`
`
`
`| 5 || 3 || E. LEDE EEFT
`
`I
`
`
`
`Qualcomm, Exh. 2016, p. 5
`Apple v. Qualcomm, 2018-01278
`
`

`

`Patent Application Publication
`
`Dec. 6, 2007 Sheet 5 of 5
`
`US 2007/0280660 A1
`
`50
`
`
`
`Detecting the environment brightness and
`getting a detected brightness value
`
`Is the
`detected brightness value
`Smaller than a predetermined
`brightness
`value?
`
`
`
`
`
`
`
`Executing the second firing process
`
`NO
`
`52
`
`Executing the first
`firing process
`
`F I. G. 5
`
`Qualcomm, Exh. 2016, p. 6
`Apple v. Qualcomm, 2018-01278
`
`

`

`US 2007/0280660 A1
`
`Dec. 6, 2007
`
`METHOD FOR FRING FLASH OF
`IMAGE-CAPTURING DEVICE
`
`BACKGROUND OF INVENTION
`1. Field of the Invention
`0001
`0002 The present invention relates to image capturing,
`and more particularly to a method for firing a flash of an
`image-capturing device.
`0003 2. Description of the Prior Art
`0004 Generally, the image-capturing devices, such as
`digital cameras, often use flashes to provide complementary
`light Sources during the image-capturing process. In some
`conventional cameras, the flash, when needed, is fired at a
`fixed intensity which cannot be adjusted according to the
`environment conditions. Thus, not only more electric power
`will be consumed, but also proper exposure compensation
`cannot be achieved due to the inability to adjust the flash
`intensity immediately.
`0005. In some advanced cameras, a preflash function is
`provided. Before the camera captures an image, it executes
`a preflash to feedback current environment brightness for
`determining the required intensity for a Subsequent main
`flash. However, the preflash would increase the power
`consumption of the battery and extend the shooting time of
`the image capturing, which results in the degradation of the
`performance for both the camera and the strobe.
`0006 Besides, when capturing a close-up image, the
`conventional camera usually fails to reduce the flash inten
`sity correspondingly. Thus, the undesirable effect of over
`exposure may often occur.
`
`SUMMARY OF INVENTION
`0007. It is therefore one object of the present invention to
`provide a method for firing a flash of an image-capturing
`device. This method can estimate a shooting distance
`according to a focusing parameter of the image-capturing
`device and dynamically determine a flash intensity accord
`ing to the shooting distance, so as to obtain improved
`exposure compensation. For example, over-exposure can be
`avoided when a close-up image is captured. In addition,
`since the preflash of the flash is skipped, the electric power
`consumption is reduced and the shooting time is shortened.
`Thus, the performance of the image-capturing device and the
`flash can be enhanced.
`0008 Another object of the present invention is to pro
`vide a method for firing a flash of an image-capturing
`device. This method can execute different flash firing pro
`cesses in response to different environment brightness, so as
`to enhance the performance of the image-capturing device
`and the flash.
`0009. According to one aspect of this invention, a method
`for firing a flash of an image-capturing device is provided.
`The method comprises the steps of performing a focusing
`procedure of the image-capturing device to generate a
`focusing parameter; estimating a shooting distance accord
`ing to the focusing parameter, determining a flash intensity
`for the flash according to the shooting distance; and firing
`the flash according to the flash intensity when the image
`capturing device captures an image.
`0010. According to another aspect of this invention, a
`method for firing a flash of an image-capturing device is
`provided. The method comprises the steps of detecting an
`environment brightness; determining whether the environ
`
`ment brightness reaches a predetermined brightness; execut
`ing a first firing process if the environment brightness
`reaches the predetermined brightness; and executing a sec
`ond firing process if the environment brightness does not
`reach the predetermined brightness; wherein the first firing
`process comprises: performing a focusing procedure of the
`image-capturing device to generate a focusing parameter;
`estimating a shooting distance according to the focusing
`parameter, determining a flash intensity for the flash accord
`ing to the shooting distance; and firing the flash according to
`the flash intensity when the image-capturing device captures
`an image.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`0011
`FIG. 1 is a flowchart showing the steps of the
`method for firing a flash according to a first embodiment of
`the invention.
`0012 FIG. 2 is a flowchart showing the steps of the
`method for firing a flash according to a second embodiment
`of the invention.
`0013 FIG. 3 is a flowchart showing the steps of the
`method for firing a flash according to a third embodiment of
`the invention.
`0014 FIG. 4 is an example showing the corresponding
`relationship between flash intensity and shooting distance as
`well as Zoom step.
`(0015 FIG. 5 is a flowchart showing the steps of the
`method for firing a flash according to a fourth embodiment
`of the invention.
`
`DETAILED DESCRIPTION
`0016. The embodiments described below are applicable
`to an image-capturing device. Such as a digital camera,
`having a flash. FIG. 1 shows a flowchart of the method for
`firing a flash according to a first embodiment of the inven
`tion. The method contains the following steps:
`0017 Step 12: performing a focusing procedure for the
`image-capturing device to generate a focusing parameter,
`0018 Step 13: estimating a shooting distance according
`to the focusing parameter;
`0019 Step 14: determining a flash intensity according to
`the shooting distance; and
`0020 Step 15: firing the flash according to the flash
`intensity when the image-capturing device captures an
`image.
`0021. In step 12, the focusing procedure determines an
`optimum position for the focus lens of the image-capturing
`device, so as to obtain the optimum image resolution. The
`focusing parameter is generated during the focusing proce
`dure and can be used in step 13 for estimating the shooting
`distance. In step 14, the longer the shooting distance is, the
`larger the determined flash intensity will be. On the contrary,
`the shorter the shooting distance, the less the determined
`flash intensity. Thus, the problem of over-exposure that
`occurs frequently when the image-capturing device carries
`out a close-up can be avoided.
`0022 FIG. 2 is a flowchart showing the method for firing
`a flash according to a second embodiment of the invention.
`The method contains the following steps:
`0023 Step 22: performing a focusing procedure for the
`image-capturing device to generate an optimum focus step
`number,
`
`Qualcomm, Exh. 2016, p. 7
`Apple v. Qualcomm, 2018-01278
`
`

`

`US 2007/0280660 A1
`
`Dec. 6, 2007
`
`0024 Step 23: estimating a shooting distance according
`to the optimum focus step number;
`0025 Step 24: determining a flash intensity according to
`the shooting distance; and
`0026 Step 25: firing the flash according to the flash
`intensity when the image-capturing device captures an
`image.
`0027. In step 22, the focusing procedure moves the focus
`lens of the image-capturing device back and forth to a
`position that can be represented by a focus step number
`relative to a reference position. Afterwards, the light sensor,
`e.g. a charge coupled device (CCD), receives the light
`passing through the focus lens, and then the corresponding
`contrast value of the focus lens at the position is calculated.
`The above process would be repeated in the focusing
`procedure, so as to generate the contrast values of the focus
`lens at other positions. The larger the contrast value is, the
`better the image resolution will be. In other words, the
`focusing procedure is used to find an optimum position (or
`an optimum focus step number), where the largest contrast
`value can be generated. Furthermore, the optimum focus
`step number can be used to estimate the shooting distance in
`step 23. The manner for estimating the shooting distance
`according to the optimum focus step number is well known
`to people skilled in the art and would not be described in
`detail here.
`0028 FIG. 3 shows a flowchart of the method for firing
`a flash according to a third embodiment of the invention. The
`method contains the following steps:
`0029 Step 32: performing a focusing procedure for the
`image-capturing device to generate a focusing parameter;
`0030 Step 33: estimating a shooting distance according
`to the focusing parameter;
`0031 Step 34: determining a flash intensity according to
`the shooting distance and a Zoom step of the image-captur
`ing device; and
`0032 Step 35: firing the flash according to the flash
`intensity when the image-capturing device captures an
`image.
`0033. In the third embodiment, the flash intensity is
`determined according to both the shooting distance and the
`Zoom step. FIG. 4 is a table showing an example of a
`corresponding relationship between the flash intensity and
`the shooting distance as well as the Zoom step. The value in
`the table represents the required flash intensity at the specific
`Zoom step and shooting distance. As shown in FIG. 4, the
`longer the shooting distance or the greater the Zoom step (i.e.
`Zoom in), the larger the required flash intensity. Conversely,
`the shorter the shooting distance or the less the Zoom step
`(i.e. Zoom out), the less the required flash intensity. Besides,
`the corresponding relationship between the flash intensity
`and the shooting distance as well as the Zoom step is
`prerecorded in a memory of the image-capturing device. In
`this manner, the required flash intensity can be easily deter
`mined by accessing the memory during the image capturing
`process.
`0034. In a preferred embodiment, the influence of expo
`Sure parameter on the required flash intensity is also con
`sidered in addition to the shooting distance and Zoom step.
`In this preferred embodiment, the exposure parameters, such
`as the aperture, the exposure value, the sensitivity (ISO),
`etc., can be adjusted according to the detected environment
`brightness. Moreover, an adjustment ratio can be generated
`according to the adjusted exposure parameters. The value of
`
`the flash intensity, which is determined according to the
`shooting distance and the Zoom step and stored in the
`memory described in the third embodiment, is then multi
`plied by the adjustment ratio, so as to adjust the flash
`intensity in response to different exposure parameter values.
`In other words, in this preferred embodiment, the required
`flash intensity is determined according to the shooting
`distance, the Zoom step and the exposure parameters.
`0035 FIG. 5 is a flowchart showing the method for firing
`a flash according to a fourth embodiment of the invention.
`In the fourth embodiment, the environment brightness is
`detected firstly. After that, the firing process is selected
`according to the detected environment brightness. The firing
`processes may include the first firing process comprising
`steps 12 to 15 of the first embodiment and the second firing
`process comprising other flash firing method. That is, dif
`ferent firing process may be used for different environment
`brightness. The fourth embodiment provides more flexibility
`in determining the flash intensity of the flash. As shown in
`FIG. 5, this method contains the following steps:
`0036 Step 50: detecting the environment brightness and
`getting a detected brightness value;
`0037 Step 51: determining whether the detected bright
`ness value is Smaller than a predetermined brightness value;
`if yes, go to step 53; otherwise, go to step 52:
`0038 Step 52: executing the first firing process (i.e., steps
`12 to 15 of the first embodiment) and stopping; and
`0039 Step 53: executing the second firing process.
`0040. In step 51, the predetermined brightness value
`varies with different image-capturing devices. When the
`detected brightness value is smaller than the predetermined
`brightness value, it means the environment brightness is too
`dark for the focusing procedure to generate the focusing
`parameter. Therefore, the first firing process is not applicable
`under Such a condition and the second firing process will be
`executed to fire the flash.
`0041. In step 53, the second firing process may actuate a
`focus illuminator when the focusing procedure is performed.
`After that, a suitable flash intensity may be concluded for the
`main flash of the image capturing. In another embodiment,
`the second firing process may also execute a preflash to
`determine the flash intensity of the main flash.
`0042. While the present invention has been shown and
`described with reference to the preferred embodiments
`thereof and in terms of the illustrative drawings, it should
`not be considered as limited thereby. Various possible modi
`fications and alterations could be conceived of by one skilled
`in the art for the form and the content of any particular
`embodiment, without departing from the scope and the spirit
`of the present invention.
`What is claimed is:
`1. A method for firing a flash of an image-capturing
`device, comprising steps of:
`performing a focusing procedure of the image-capturing
`device to generate a focusing parameter;
`estimating a shooting distance according to the focusing
`parameter,
`determining a flash intensity for the flash according to the
`shooting distance; and
`firing the flash according to the flash intensity when the
`image-capturing device captures an image.
`2. The method according to claim 1, wherein the focusing
`parameter is an optimum focus step number.
`
`Qualcomm, Exh. 2016, p. 8
`Apple v. Qualcomm, 2018-01278
`
`

`

`US 2007/0280660 A1
`
`Dec. 6, 2007
`
`3. The method according to claim 1, wherein the flash
`intensity is determined by the shooting distance and a Zoom
`step of the image-capturing device.
`4. The method according to claim 3, wherein a corre
`sponding relationship between the flash intensity and the
`shooting distance as well as the Zoom step is prerecorded in
`the image-capturing device.
`5. The method according to claim 4, further comprising:
`adjusting the flash intensity according to the correspond
`ing relationship and an adjustment ratio:
`wherein the adjustment ratio is determined according to
`an exposure parameter of the image-capturing device.
`6. The method according to claim 3, wherein the flash
`intensity is determined according to the shooting distance,
`the Zoom step and an exposure parameter of the image
`capturing device.
`7. The method according to claim 1, wherein the flash
`intensity is determined according to the shooting distance
`and an exposure parameter of the image-capturing device.
`8. The method according to claim 1, further comprising:
`detecting an environment brightness prior to performing
`the focusing procedure; and
`activating a focus illuminator if the environment bright
`ness does not reach a predetermined brightness.
`9. A method for firing a flash of an image-capturing
`device, comprising steps of:
`detecting an environment brightness;
`determining whether the environment brightness reaches
`a predetermined brightness;
`executing a first firing process if the environment bright
`ness reaches the predetermined brightness; and
`executing a second firing process if the environment
`brightness does not reach the predetermined brightness;
`wherein the first firing process comprises:
`performing a focusing procedure of the image-capturing
`device to generate a focusing parameter;
`estimating a shooting distance according to the focusing
`parameter;
`determining a flash intensity for the flash according to the
`shooting distance; and
`firing the flash according to the flash intensity when the
`image-capturing device captures an image.
`10. The method according to claim 9, wherein the second
`firing process comprises:
`executing a preflash of the flash to determine a flash
`intensity for the flash; and
`
`executing a mainflash of the flash according to the flash
`intensity when the image-capturing device captures an
`image.
`11. The method according to claim 9, wherein the second
`firing process comprises:
`actuating a focus illuminator and executing a focusing
`procedure of the image-capturing device to generate a
`focusing parameter;
`estimating a shooting distance according to the focusing
`parameter,
`determining a flash intensity for the flash according to the
`shooting distance; and
`firing the flash according to the flash intensity when the
`image-capturing device captures an image.
`12. The method according to claim 9, wherein the focus
`ing parameter is an optimum focus step number.
`13. The method according to claim 9, wherein the flash
`intensity is determined according to the shooting distance
`and a Zoom step of the image-capturing device.
`14. The method according to claim 13, wherein a corre
`sponding relationship between the flash intensity and the
`shooting distance as well as the Zoom step is prerecorded in
`the image-capturing device.
`15. The method according to claim 14, further compris
`ing:
`adjusting the flash intensity according to the correspond
`ing relationship and an adjustment ratio:
`wherein the adjustment ratio is determined according to
`an exposure parameter of the image-capturing device.
`16. The method according to claim 13, wherein the flash
`intensity is determined according to the shooting distance,
`the Zoom step and an exposure parameter of the image
`capturing device.
`17. The method according to claim 9, wherein the flash
`intensity is determined according to the shooting distance
`and an exposure parameter of the image-capturing device.
`18. The method according to claim 15, wherein the
`exposure parameter is adjusted according to the detected
`environment brightness.
`19. The method according to claim 16, wherein the
`exposure parameter is adjusted according to the detected
`environment brightness.
`20. The method according to claim 17, wherein the
`exposure parameter is adjusted according to the detected
`environment brightness.
`
`k
`
`k
`
`k
`
`k
`
`k
`
`Qualcomm, Exh. 2016, p. 9
`Apple v. Qualcomm, 2018-01278
`
`