V4L2_META_FMT_BCM2835_ISP_STATS (‘BSTA’)¶
BCM2835 ISP Statistics
Description¶
The BCM2835 ISP hardware calculate image statistics for an input Bayer frame.
These statistics are obtained from the “bcm2835-isp0-capture3” device node
using the v4l2_meta_format
interface. They are formatted as described
by the bcm2835_isp_stats
structure below.
#define DEFAULT_AWB_REGIONS_X 16
#define DEFAULT_AWB_REGIONS_Y 12
#define NUM_HISTOGRAMS 2
#define NUM_HISTOGRAM_BINS 128
#define AWB_REGIONS (DEFAULT_AWB_REGIONS_X * DEFAULT_AWB_REGIONS_Y)
#define FLOATING_REGIONS 16
#define AGC_REGIONS 16
#define FOCUS_REGIONS 12
-
struct bcm2835_isp_stats_hist¶
Histogram statistics
Definition:
struct bcm2835_isp_stats_hist {
__u32 r_hist[NUM_HISTOGRAM_BINS];
__u32 g_hist[NUM_HISTOGRAM_BINS];
__u32 b_hist[NUM_HISTOGRAM_BINS];
};
Members
r_hist
Red channel histogram.
g_hist
Combined green channel histogram.
b_hist
Blue channel histogram.
-
struct bcm2835_isp_stats_region¶
Region sums.
Definition:
struct bcm2835_isp_stats_region {
__u32 counted;
__u32 notcounted;
__u64 r_sum;
__u64 g_sum;
__u64 b_sum;
};
Members
counted
The number of 2x2 bayer tiles accumulated.
notcounted
The number of 2x2 bayer tiles not accumulated.
r_sum
Total sum of counted pixels in the red channel for a region.
g_sum
Total sum of counted pixels in the green channel for a region.
b_sum
Total sum of counted pixels in the blue channel for a region.
-
struct bcm2835_isp_stats_focus¶
Focus statistics.
Definition:
struct bcm2835_isp_stats_focus {
__u64 contrast_val[2][2];
__u32 contrast_val_num[2][2];
};
Members
contrast_val
Focus measure - accumulated output of the focus filter. In the first dimension, index [0] counts pixels below a preset threshold, and index [1] counts pixels above the threshold. In the second dimension, index [0] uses the first predefined filter, and index [1] uses the second predefined filter.
contrast_val_num
The number of counted pixels in the above accumulation.
-
struct bcm2835_isp_stats¶
ISP statistics.
Definition:
struct bcm2835_isp_stats {
__u32 version;
__u32 size;
struct bcm2835_isp_stats_hist hist[NUM_HISTOGRAMS];
struct bcm2835_isp_stats_region awb_stats[AWB_REGIONS];
struct bcm2835_isp_stats_region floating_stats[FLOATING_REGIONS];
struct bcm2835_isp_stats_region agc_stats[AGC_REGIONS];
struct bcm2835_isp_stats_focus focus_stats[FOCUS_REGIONS];
};
Members
version
Version of the bcm2835_isp_stats structure.
size
Size of the bcm2835_isp_stats structure.
hist
Histogram statistics for the entire image.
awb_stats
Statistics for the regions defined for AWB calculations.
floating_stats
Statistics for arbitrarily placed (floating) regions.
agc_stats
Statistics for the regions defined for AGC calculations.
focus_stats
Focus filter statistics for the focus regions.