Temporal smoothing in image capture systems

1. A system comprising:

an image sensor configured to capture a sequence of images; and

a processing apparatus configured to:

access the sequence of images from the image sensor;

determine a sequence of parameters for respective images in the sequence of images based on pixel values of the respective images;

store the sequence of images in a buffer;

determine a temporally smoothed parameter for a current image in the sequence of images based on the sequence of parameters, wherein the sequence of parameters includes parameters for images in the sequence of images that were captured after the current image; and

apply image processing to the current image based on the temporally smoothed parameter to obtain a processed image.

2. The system of claim 1 , in which the processing apparatus includes an image signal processor and the temporally smoothed parameter is an automatic exposure gain that is applied by the image signal processor to all color channels of the current image.

3. The system of claim 1 , in which the temporally smoothed parameter is a tuple of automatic white balance gains that are applied to respective color channels of the current image.

4. The system of claim 3 , in which the tuple of automatic white balance gains includes a red channel gain that is applied to a red channel of the current image and a blue channel gain that is applied to a blue channel of the current image.

5. The system of claim 1 , in which the temporally smoothed parameter is a tuple of global tone mapping gains or output values for respective ranges of input pixel values.

6. The system of claim 1 , in which the processing apparatus is configured to:

apply a filter to the sequence of parameters to obtain the temporally smoothed parameter.

7. The system of claim 1 , in which the processing apparatus is configured to:

apply a bilateral filter followed by a shorter term average filter to the sequence of parameters to obtain the temporally smoothed parameter.

8. The system of claim 1 , comprising:

an image capture module that includes the image sensor, a connector, and an integrated mechanical stabilization system configured to control an orientation of the image sensor relative to the connector.

9. The system of claim 1 , in which the processing apparatus is configured to:

determine a temporally smoothed rotation for the current image in the sequence of images based on a sequence of rotations associated with respective images in the sequence of images, wherein the sequence of rotations includes rotations for images in the sequence of images that were captured after the current image; and

apply, using an electronic image stabilization module, the temporally smoothed rotation to the processed image.

10. The system of claim 9 , comprising:

an aerial vehicle configured to be removably attached to the image capture module by the connector and to fly while carrying the image capture module; and

a handheld module configured to be removably attached to the image capture module by the connector, wherein the handheld module includes a battery and a display configured to display images received from the image sensor via conductors of the connector.

11. The system of claim 9 , in which the processing apparatus is inside the image capture module.

12. The system of claim 1 , in which the processing apparatus is configured to:

store the sequence of parameters in the buffer with their respective images in the sequence of images.

13. A method comprising:

accessing a sequence of images from an image sensor;

determining a sequence of parameters for respective images in the sequence of images based on pixel values of the respective images;

storing the sequence of images in a buffer;

determining a temporally smoothed parameter for a current image in the sequence of images based on the sequence of parameters, wherein the sequence of parameters includes parameters for images in the sequence of images that were captured after the current image;

applying image processing to the current image based on the temporally smoothed parameter to obtain a processed image; and

storing, displaying, or transmitting an output image based on the processed image.

14. The method of claim 13 , in which the temporally smoothed parameter is an automatic exposure gain that is applied by an image signal processor to all color channels of current image.

15. The method of claim 13 , in which the temporally smoothed parameter is a tuple of automatic white balance gains that are applied to respective color channels of the current image.

16. The method of claim 13 , in which the temporally smoothed parameter is a tuple of global tone mapping gains or output values for respective ranges of input pixel values.

17. The method of claim 13 , comprising:

determining a temporally smoothed rotation for the current image in the sequence of images based on a sequence of rotations associated with respective images in the sequence of images, wherein the sequence of rotations includes rotations for images in the sequence of images that were captured after the current image; and

applying, using an electronic image stabilization module, the temporally smoothed rotation to the processed image.

18. The method of claim 13 , comprising:

applying a bilateral filter followed by a shorter term average filter to the sequence of parameters to obtain the temporally smoothed parameter.

19. A system comprising:

an image sensor configured to capture a sequence of images;

a buffer configured to store the sequence of images; and

an image signal processor configured to:

determine a sequence of parameters for respective images in the sequence of images based on pixel values of the respective images;

apply a non-causal filter to the sequence of parameters to obtain a temporally smoothed parameter for a current image in the sequence of images; and

apply image processing to the current image based on the temporally smoothed parameter to obtain a processed image.

20. The system of claim 19 , in which the processing apparatus is configured to:

determine a temporally smoothed rotation for the current image in the sequence of images based on a sequence of rotations associated with respective images in the sequence of images, wherein the sequence of rotations includes rotations for images in the sequence of images that were captured after the current image; and

apply, using an electronic image stabilization module, the temporally smoothed rotation to the processed image.