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-rw-r--r--src/ipa/libipa/camera_sensor_helper.cpp94
1 files changed, 94 insertions, 0 deletions
diff --git a/src/ipa/libipa/camera_sensor_helper.cpp b/src/ipa/libipa/camera_sensor_helper.cpp
index 29a00d7f..2f6e7282 100644
--- a/src/ipa/libipa/camera_sensor_helper.cpp
+++ b/src/ipa/libipa/camera_sensor_helper.cpp
@@ -8,6 +8,7 @@
#include "camera_sensor_helper.h"
#include <cmath>
+#include <limits>
#include <libcamera/base/log.h>
@@ -398,6 +399,99 @@ static constexpr double expGainDb(double step)
return log2_10 * step / 20;
}
+class CameraSensorHelperAr0144 : public CameraSensorHelper
+{
+public:
+ CameraSensorHelperAr0144()
+ {
+ /* Power-on default value: 168 at 12bits. */
+ blackLevel_ = 2688;
+ }
+
+ uint32_t gainCode(double gain) const override
+ {
+ /* The recommended minimum gain is 1.6842 to avoid artifacts. */
+ gain = std::clamp(gain, 1.0 / (1.0 - 13.0 / 32.0), 18.45);
+
+ /*
+ * The analogue gain is made of a coarse exponential gain in
+ * the range [2^0, 2^4] and a fine inversely linear gain in the
+ * range [1.0, 2.0[. There is an additional fixed 1.153125
+ * multiplier when the coarse gain reaches 2^2.
+ */
+
+ if (gain > 4.0)
+ gain /= 1.153125;
+
+ unsigned int coarse = std::log2(gain);
+ unsigned int fine = (1 - (1 << coarse) / gain) * 32;
+
+ /* The fine gain rounding depends on the coarse gain. */
+ if (coarse == 1 || coarse == 3)
+ fine &= ~1;
+ else if (coarse == 4)
+ fine &= ~3;
+
+ return (coarse << 4) | (fine & 0xf);
+ }
+
+ double gain(uint32_t gainCode) const override
+ {
+ unsigned int coarse = gainCode >> 4;
+ unsigned int fine = gainCode & 0xf;
+ unsigned int d1;
+ double d2, m;
+
+ switch (coarse) {
+ default:
+ case 0:
+ d1 = 1;
+ d2 = 32.0;
+ m = 1.0;
+ break;
+ case 1:
+ d1 = 2;
+ d2 = 16.0;
+ m = 1.0;
+ break;
+ case 2:
+ d1 = 1;
+ d2 = 32.0;
+ m = 1.153125;
+ break;
+ case 3:
+ d1 = 2;
+ d2 = 16.0;
+ m = 1.153125;
+ break;
+ case 4:
+ d1 = 4;
+ d2 = 8.0;
+ m = 1.153125;
+ break;
+ }
+
+ /*
+ * With infinite precision, the calculated gain would be exact,
+ * and the reverse conversion with gainCode() would produce the
+ * same gain code. In the real world, rounding errors may cause
+ * the calculated gain to be lower by an amount negligible for
+ * all purposes, except for the reverse conversion. Converting
+ * the gain to a gain code could then return the quantized value
+ * just lower than the original gain code. To avoid this, tests
+ * showed that adding the machine epsilon to the multiplier m is
+ * sufficient.
+ */
+ m += std::numeric_limits<decltype(m)>::epsilon();
+
+ return m * (1 << coarse) / (1.0 - (fine / d1) / d2);
+ }
+
+private:
+ static constexpr double kStep_ = 16;
+};
+REGISTER_CAMERA_SENSOR_HELPER("ar0144", CameraSensorHelperAr0144)
+
class CameraSensorHelperAr0521 : public CameraSensorHelper
{
public: