Combined mechanical and electronic image stabilization
Systems and methods are disclosed for image signal processing. For example, methods may include determining a sequence of orientation estimates based on sensor data from one or more motion sensors; based on the sequence of orientation estimates, invoking a mechanical stabilization system to reject motions of an image sensor occurring within a first operating bandwidth with an upper cutoff frequency; receiving an image from the image sensor; based on the sequence of orientation estimates, invoking an electronic image stabilization module to correct the image for rotations of the image sensor occurring within a second operating bandwidth with a lower cutoff frequency to obtain a stabilized image, wherein the lower cutoff frequency is greater than the upper cutoff frequency; and storing, displaying, or transmitting an output image based on the stabilized image.
1. A method comprising:
adjusting cutoff frequencies based on a mode selection of an image capture device;
detecting an environmental condition of the image capture device;
adjusting the cutoff frequencies based on the environmental condition;
determining a temperature of a motor of the image capture device;
adjusting the cutoff frequencies based on the temperature;
determining a state of charge of a battery of the image capture device; and
adjusting the cutoff frequencies based on the state of charge of the battery.
2. The method of claim 1 , wherein the mode selection indicates a high image quality mode, the method further comprising:
increasing an upper cutoff frequency of the cutoff frequencies based on the mode selection.
3. The method of claim 1 , wherein the mode selection indicates a high image quality mode, the method further comprising:
increasing a lower cutoff frequency of the cutoff frequencies based on the mode selection.
4. The method of claim 1 , wherein the mode selection indicates a low image quality mode, the method further comprising:
decreasing an upper cutoff frequency of the cutoff frequencies based on the mode selection.
5. The method of claim 1 , wherein the mode selection indicates a low image quality mode, the method further comprising:
decreasing a lower cutoff frequency of the cutoff frequencies based on the mode selection.
6. The method of claim 1 , wherein the environmental condition includes a low light condition, a high motion condition, a high noise condition, or a high contrast condition.
7. The method of claim 1 , wherein determining the temperature of the motor is based on a thermodynamic model of the motor.
8. The method of claim 1 , wherein determining the temperature of the motor is based on a direct measurement.
9. An image capture device comprising:
an image sensor configured to capture an image;
a mechanical stabilization system that has a first operating bandwidth, the mechanical stabilization system comprising a motor configured to control an orientation of the image sensor;
an electronic stabilization module that has a second operating bandwidth, the electronic stabilization system configured to correct images for rotations of the image sensor; and
a processing apparatus configured to:
determine a temperature of the motor; and
adjust a cutoff frequency of the first operating bandwidth or the second operating bandwidth based on the temperature of the motor.
10. The image capture device of claim 9 further comprising:
a thermistor configured to sample the temperature of the motor.
11. The image capture device of claim 9 , wherein the processing apparatus is configured to determine the temperature of the motor based on a thermodynamic model.
12. The image capture device of claim 11 , wherein the thermodynamic model is configured to estimate the temperature of the motor based on an ambient temperature.
13. The image capture device of claim 11 , wherein the thermodynamic model is configured to estimate the temperature of the motor based on a worst case fixed value.
14. The image capture device of claim 9 further comprising:
a motor controller configured to sample a current applied to the motor.
15. The image capture device of claim 14 , wherein the processing apparatus is configured to determine the temperature of the motor based on the current applied to the motor.
16. An image capture device comprising:
an image sensor configured to capture an image;
a mechanical stabilization system that has a first operating bandwidth, the mechanical stabilization system comprising a motor configured to control an orientation of the image sensor;
an electronic stabilization module that has a second operating bandwidth, the electronic stabilization system configured to correct images for rotations of the image sensor;
a battery configured to supply power to the motor; and
a processing apparatus configured to:
determine a state of charge of the battery; and
adjust a cutoff frequency of the first operating bandwidth or the second operating bandwidth based on the state of charge of the battery.
17. The image capture device of claim 16 , wherein the state of charge of the battery is based on a voltage measurement of the battery.
18. The image capture device of claim 16 , wherein the processing apparatus is configured to compare the state of charge of the battery to a minimum charge level.
19. The image capture device of claim 18 , wherein the processing apparatus is configured to reduce the cutoff frequency of the first operating bandwidth on a condition that the state of charge of the battery is below the minimum charge level.
20. The image capture device of claim 18 , wherein the processing apparatus is configured to adjust the cutoff frequency of the first operating bandwidth or the second operating bandwidth based on a difference between the state of charge of the battery and the minimum charge level.