Software Based Photoflash synchronization of camera equipped portable media device and external lighting apparatus

• US 20090136225A1
• Filed: 11/25/2008
• Published: 05/28/2009
• Est. Priority Date: 11/28/2007
• Status: Active Grant

• Current Assignee: Bowei Gai, Brett Bilbrey, Heer Robin Gandhi, Henry Teng, Osei Kofi Poku
• Original Assignee: Bowei Gai, Brett Bilbrey, Heer Robin Gandhi, Henry Teng, Osei Kofi Poku
• Inventors: Bilbrey, Brett, Poku, Osei Kofi, Teng, Henry, Gandhi, Heer Robin, Gai, Bowei
• Granted Patent: US 7,949,249 B2
• Time in Patent Office: Days
• US Class Current: 396/180
• CPC Class Codes: G03B 15/05 Combinations of cameras with electronic flash apparatus; Electronic flash units
• CPC Class Codes: G03B 2215/0514 Separate unit
• CPC Class Codes: G03B 2215/056 Connection with camera, e.g. adapter

Abstract

Methods of using software to synchronize the control of a camera on portable media device with the photoflash on an external lighting apparatus.

The Camera-Equipped Portable Media Device (CEPMD) utilizes an External Lighting Apparatus (ELA) as a light source to improve the lighting conditions for portable media device photography. Both ELA and CEPMD are controlled by software, which synchronize the photoflash image capture as well as post process the image to further enhance the image quality. Furthermore, in a preferred ELA embodiment, it acts as a protective case for the CEPMD.

Claims

1. A method of synchronizing a portable media device camera shutter trigger and an external lighting apparatus (ELA) with software, the method comprising the steps of:

1) providing hardware and software comprising

a) a camera-equipped portable media device(CEPMD) having a camera shutter trigger;

b) an external lighting apparatus having one or more trigger signals for triggering a flash;

c) a means for connecting the portable media device and the lighting apparatus;

d) a communication protocol between the CEPMD and ELA,

e) synchronization software for controlling the camera shutter trigger and the one or more external lighting triggers; and

2) controlling via the synchronization software the timing of the shutter trigger and the one or more lighting trigger signals to optimally illuminate a subject when a picture is taken to capture a photoflash image.

2. The method as defined in claim 1, wherein a delay is either preset in the synchronization software or is calculated from current user settings, surrounding lighting conditions and/or distance of the subject to the camera.

3. The method as defined in claim 1, wherein the communication can be any standard communication protocol available on the CEPMD or a proprietary protocol using voice and audio signals available on the CEPMD.

4. The method as defined in claim 3, wherein the standard communication protocol is selected from the group consisting of USB, serial, Firewire, Wi-Fi, Bluetooth and infrared

5. The method as defined in claim 1, wherein synchronization signals can be used for feedback signals, and physical buttons on the external lighting apparatus optionally turn on CEPMD'"'"'s camera functionality and/or signal the software to trigger a synchronized flash and camera shutter event.

6. The method as defined in claim 1, wherein the external lighting apparatus is connected to the portable media device via a connector, and control signals from and/or to the portable media device from the external lighting apparatus are transmitted via the connector.

7. The method as defined in claim 6, wherein the external lighting apparatus draws power from the portable media device through the connector.

8. The method as defined in claim 7, wherein the connector is a pass through connection, such that other devices can connect to the portable media device while the connector is connected to the external lighting apparatus.

9. The method as defined in claim 1, wherein the external lighting apparatus comprises one or more LED preview lights for camera preview and video camera photography;

one or more camera flash lights for camera still photography;

a physical on/off button; and

optionally, one or more items selected from the group consisting of

     1) a zoom or macro lens function;

     2) a range finder;

     3) an auto/manual focus function;

     4) a pass through connector that connects to the portable media device; and

     5) a microcontroller to communicate with the portable media device.

10. The method as defined in claim 1, wherein the external lighting apparatus serves as a protective carrying case for the portable media device.

11. The method as defined in claim 1, wherein the portable media device is a Portable Media Player (PMP), a mobile phone, or a Personal Digital Assistant (PDA).

12. The method as defined in claim 9, wherein the one or more flash lights and one or more preview lights are triggered by the software or a physical hardware button.

13. The method as defined in claim 1, wherein the means for connecting the CEPMD to the ELA is a physical wire, or the external lighting apparatus syncs wirelessly with the camera synchronization software via a wireless module having its own power source, and the wireless module connects to the portable media device via its built-in wireless protocols.

14. The method as defined in claim 1, wherein the method is optimized by minimizing the total timing error in the hardware, the synchronization software and communication between the CEPMD and the ELA, and/or increasing the camera exposure time, such that the total timing error is smaller than the duration of exposure.

15. The method as defined in claim 1, wherein when exposure or timing control of the CEPMD is not available, the synchronization software records multiple images in consecutive sessions and processes the multiple images to regenerate a composite image.

16. The method as defined in claim 15, wherein the first image is captured without photoflash, and is used as a baseline image for later comparisons.

17. The method as defined in claim 15, wherein the synchronization software compares a first baseline image to subsequent images.

18. The method as defined in claim 15, where the synchronization software minimizes the amount of time the camera is in a processing mode and maximizes the amount of time the camera is in exposure mode.

19. The method as defined in claim 18, wherein the processing mode duration is the sum of 1) the time it takes for the camera to stop exposure and record the data and 2) the time it takes to prepare the camera for another capture.

20. The method as defined in claim 15, wherein when photoflash capture is split between multiple images, the synchronization software post processes the partially lit images to produce one complete composite photoflash image.

21. The method as defined in claim 1, wherein control of the photoflash settings is manually selected by the user or is automatically adjusted by the synchronization software.

22. The method as defined in claim 1, wherein the synchronization software improves a captured image by post processing the image using one or more techniques selected from the group consisting of manual/auto white balancing, blending, sharpening, High Dynamic Range processing, exposure blending and extracting information from multiple illuminations of the same image.

23. An apparatus for synchronizing a portable media device camera and an external lighting apparatus, the apparatus comprising:

a) a camera-equipped portable media device having a shutter trigger;

b) an external lighting apparatus having one or more trigger signals for triggering a flash;

c) synchronization software for controlling the shutter trigger and the one or more lighting apparatus triggers;

d) a means for connecting the portable media device to the lighting apparatus; and

e) a communication protocol between the camera-equipped portable media device and the external lighting apparatus.