Method for Controlling Flash Timing of Extension Flash Module

Abstract

The present invention provides a method for controlling flash timing of an extension flash module cooperating with a mobile device. The method includes: detecting a specific event, wherein a time period from when the specific event occurs to the start of an exposure of the first row of a photo sensor is a constant; determining whether there is one single flashable time period wherein one flash is receivable by every row of the photo sensor; when there is such a single flashable time period, conducting one single flash after a delay time from the specific event; and when there is no such single flashable time period, conducting a first flash after a delay time from the specific event, and conducting a second flash after a delay time from the first flash.

What is claimed is: 
     
         1 . A method for controlling flash timing of an extension flash module cooperating with a mobile device to provide supplemental light when the mobile device having an image retrieval device is taking a photo, the image retrieval device including pixels arranged in N rows, wherein N is a positive integer, the method comprising:
 detecting a specific event, wherein a time period from when the specific event occurs to a start of an exposure of the first row of the image retrieval device is a constant;   determining whether there is one single flashable time period wherein one flash is receivable by every row of the image retrieval device;   when there is a single flashable time period wherein one flash is receivable by every row of the image retrieval device, conducting one single flash after a delay time from the specific event; and   when there is no such single flashable time period, conducting a first flash after a delay time from the specific event, and conducting a second flash after a delay time from the first flash.   
     
     
         2 . The method of  claim 1 , wherein the step of determining whether there is one single flashable time period wherein one flash is receivable by every row of the image retrieval device, includes:
 detecting an intensity of an ambient light;   comparing the intensity of the ambient light with a predetermined threshold;   when the intensity of the ambient light is lower than the predetermined threshold, determining that there is one single flashable time period wherein one flash is receivable by every row of the image retrieval device; and   when the intensity of the ambient light is higher than the predetermined threshold, determining that there is not one single flashable time period wherein one flash is receivable by every row of the image retrieval device.   
     
     
         3 . The method of  claim 2 , further comprising: storing different predetermined thresholds corresponding to different types of mobile devices in a storage device in the extension flash module, or setting different predetermined thresholds corresponding to different types of mobile devices in an application program by which the mobile device controls the extension flash module. 
     
     
         4 . The method of  claim 1 , further comprising: conducting a third flash after a delay time from the second flash. 
     
     
         5 . The method of  claim 1 , wherein the step of determining whether there is one single flashable time period wherein one flash is receivable by every row of the image retrieval device, includes:
 detecting an intensity of an ambient light;   comparing the intensity of the ambient light with a first predetermined threshold and a second predetermined threshold;   when the intensity of the ambient light is lower than the first predetermined threshold, determining that there is one single flashable time period wherein one flash is receivable by every row of the image retrieval device;   when the intensity of the ambient light is higher than the first predetermined threshold and lower than the second predetermined threshold, determining that two flashes are required; and   when the intensity of the ambient light is higher than the second predetermined threshold, determining that three or more flashes are required.   
     
     
         6 . The method of  claim 5 , further comprising: storing different predetermined thresholds corresponding to different types of mobile devices in a storage device in the extension flash module, or setting different predetermined thresholds corresponding to different types of mobile devices in an application program by which the mobile device controls the extension flash module. 
     
     
         7 . 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, and the method further comprising: when P+Q<N, conducting a third flash after a delay time from the second flash, wherein P and Q are both positive integers. 
     
     
         8 . The method of  claim 1 , wherein the first row has a common flashable time period with the a th  row and any row before the a th  row, but does not have a flashable time period with the b th  row and any row after the b th  row, while the N th  row has a common flashable time period with the c th  row and any row after the c th  row, but does not have a flashable time period with the d th  row and any row before the d th  row, and the steps of conducting a first flash after a delay time from the specific event, and conducting a second flash after a delay time from the first flash comprise:
 conducting the first flash before the first row ends exposure and within an exposure time period of the X th  row; and   conducting the second flash after the N th  row begins exposure and within an exposure time period of the Y th  row;   wherein d≦X≦a, and c≦Y≦b, and wherein a, b, c, d, X, and Y are positive integers.   
     
     
         9 . The method of  claim 1 , wherein the step of determining whether there is one single flashable time period wherein one flash is receivable by every row of the image retrieval device, includes:
 conducting a photo-taking testing exposure procedure wherein an exposure of the pixels is made according to an ambient light;   comparing the brightnesses of the pixels with a reference value to determine whether there is any row having a brightness lower than the reference value;   when there is no row having a brightness lower than the reference value, determining that there is one single flashable time period wherein one flash is receivable by every row of the image retrieval device; and   when there is a row having a brightness lower than the reference value, determining that there is not one single flashable time period wherein one flash is receivable by every row of the image retrieval device.   
     
     
         10 . The method of  claim 9 , further comprising:
 determining a number (P) of rows of pixels having brightnesses higher than the reference value; and   comparing the number (P) with a total number (N) of the rows, to determine a number of flashes required for all the rows to receive at least one flash;   wherein P and N are positive integers.   
     
     
         11 . A method for controlling flash timing of an extension flash module cooperating with a mobile device to provide supplemental light when the mobile device having an image retrieval device is taking a photo, the image retrieval device including pixels arranged in N rows, wherein N is a positive integer, the method comprising:
 controlling a timing of a first flash of the extension flash module; and   conducting a second flash or more flashes after a delay time from the first flash;   whereby all the flashes in combination expose all the rows such that the exposed pixels in combination compose a complete photo.