TECHNIQUES FOR COLLECTION OF AUTO-FOCUS STATISTICS
First Claim
1. An image signal processing system comprising:
- a front-end pixel processing unit configured to receive a frame of raw image data acquired using a digital image sensor, wherein the front-end pixel processing unit comprises a statistics collection engine having auto-focus (AF) statistics having fine resolution filtering logic configured to process the raw image data to provide fine resolution AF statistics and coarse resolution filtering logic configured to process the raw image data to provide coarse AF statistics.
1 Assignment
0 Petitions
Accused Products
Abstract
Various techniques are disclosed for collecting and processing auto-focus statistics data in an image signal processor (ISP). In one embodiment, a statistics collection engine in an ISP front-end processing unit may be configured to collect coarse (based on decimated raw data) and fine auto-focus statistics. Coarse auto-focus statistics may be collected on decimated Bayer RGB data and/or on linear camera luma values. Fine auto-focus statistics may be collected on raw Bayer RGB using a combination of a horizontal filter and edge detector, or may be collected on BayerY data (by applying a 3×1 transform to the raw Bayer RGB data). Edge sums may be accumulated using the filter outputs to determine auto-focus statistics.
45 Citations
25 Claims
-
1. An image signal processing system comprising:
a front-end pixel processing unit configured to receive a frame of raw image data acquired using a digital image sensor, wherein the front-end pixel processing unit comprises a statistics collection engine having auto-focus (AF) statistics having fine resolution filtering logic configured to process the raw image data to provide fine resolution AF statistics and coarse resolution filtering logic configured to process the raw image data to provide coarse AF statistics. - View Dependent Claims (2, 3, 4, 5, 6, 7, 9)
-
10. A method for collecting auto-focus statistics comprising:
-
receiving an image frame having raw image pixels acquired using an image sensor, the raw image pixels comprising red, blue, and green color components; applying a horizontal filter to the raw image pixels to determine edge sum values for each of the red, blue, and green color components for the image frame; applying a transform function to convert the raw image pixels into corresponding luma values; applying first and second filters to the converted luma values and determining luma edge sum values for each of the first and second filters for the image frame; decimating the raw image pixels and applying one or more linear or non-linear transforms to convert the raw image pixels into a camera luma and chroma color space; and applying third and fourth filters to the camera luma (camY) values and determining luma edge sum values for each of the third and fourth filters for the image frame. - View Dependent Claims (11, 12, 13, 14)
-
-
15. A method for acquiring auto-focus statistics comprising:
-
determining coarse auto-focus (AF) statistics by applying first and second filters to a first signal comprising decimated image data and determining a first accumulated edge sum value corresponding to a first window using the output of the first filter and a second accumulated edge sum value corresponding to a second window based on the output of the second filter; determining fine AF statistics by applying third and fourth filters to a second signal comprising non-decimated image data and determining a third accumulated edge sum value corresponding to a third window using the output of the third filter and a fourth accumulated edge sum value corresponding to a fourth window based on the output of the fourth filter. - View Dependent Claims (16, 17)
-
-
18. An electronic device comprising:
-
a digital image sensor; an interface configured to communicate with the digital image sensor; a memory device; a display device configured to display a visual representation of an image scene corresponding to raw image data acquired by the digital image sensor; and an image signal processing sub-system comprising a front-end pixel processing unit having a statistics collection engine comprising auto-focus statistics logic configured to collect a combination of fine and coarse auto-focus statistics over a plurality of windows. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25)
-
Specification