Method and apparatus for reducing the effect of EMI on receiver sensitivity in a camera phone
View Patent ↗A mobile communication device ( 100 ) includes a camera module ( 102 ) which provides an image stream when the camera module is active. The image stream is used to display images on a display ( 114 ) to provide a viewfinder function so that a user of the mobile communication device can see to what the camera is aimed. While the mobile communication device is operating in camera mode, the mobile communication device receives a signal at a radio receiver ( 104 ) during a time slot of a time division multiple access frame ( 110 ). To prevent the camera module from interfering with the receiver operation, the camera module operation is suspended during the receiver time slot.
1. A method of controlling operation of a camera system in a mobile communication device, comprising:
initiating a camera mode on the mobile communication device;
capturing images at a camera module of the mobile communication device at a capture rate thereby producing a camera module output stream;
transferring the images from the camera module to a display of the mobile communication device at a display rate, thereby providing periods of inactivity in the camera module output stream; and
receiving information at a receiver of the mobile communication device during a receive time slot of a time division multiple access air interface, and wherein the time slot occurs during a period of inactivity of the camera module output.
2. A method of controlling operation of a camera as defined in claim 1 , wherein the display rate is half the capture rate.
3. A method of controlling operation of a camera as defined in claim 2 , wherein the capture rate is 30 frames per second.
4. A method of controlling operation of a camera as defined in claim 1 , wherein the period of inactivity in the camera module output stream is at least 15 milliseconds in duration.
5. A method of controlling operation of a camera as defined in claim 1 , further comprising suspending operation of the camera module during the receive time slot.
6. A method of controlling operation of a camera as defined in claim 1 , wherein transferring the images from the camera module to the display is performed where the display rate is less than the capture rate.
7. A method of controlling the effect of electromagnetic interference (EMI) from a camera module of a mobile communication device on a radio frequency (RF) receiver of the mobile communication device, comprising:
producing a camera module output stream from a camera module of the mobile communication device, the camera module output stream being a series of images captured by the camera module; and
suspending operation of the camera module upon the occurrence of a receive time slot of a time division multiple access air interface;
wherein producing the camera module output stream comprises capturing images at capture rate and outputting them in the camera module output stream at a display rate, wherein the display rate is less than the capture rate, thereby providing periods of inactivity in the camera module output stream, and wherein suspending operation of the camera module occurs as a result of one of the periods of inactivity.
8. A method of controlling the effect of EMI, as defined in claim 7 , further comprising displaying the series of images of the camera module output stream on a display of the mobile communication device.
9. A method of controlling the effect of EMI, as defined in claim 7 , wherein suspending operation of the camera module comprises asserting a suspend signal at the camera module.
10. A method of controlling the effect of EMI, as defined in claim 9 , wherein the suspend signal is asserted by a baseband processor of the mobile communication device.
11. A mobile communication device, comprising:
a camera module;
a display controller coupled to a display and to the camera module for displaying information received from the camera module on the display;
a receiver for receiving a signal at a prescribed time; and
a controller for suspending operation of the camera module during the prescribed time slot;
wherein the camera module captures images a capture rate, and outputs them to the display controller at a display rate, and wherein the display rate is less than the capture rate.
12. The mobile communication device of claim 11 , wherein the controller for suspending operation of the camera module is a baseband processor of the mobile communication device.