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Diffstat (limited to 'src/ipa/raspberrypi/cam_helper.hpp')
| -rw-r--r-- | src/ipa/raspberrypi/cam_helper.hpp | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/src/ipa/raspberrypi/cam_helper.hpp b/src/ipa/raspberrypi/cam_helper.hpp new file mode 100644 index 00000000..0c8aa29a --- /dev/null +++ b/src/ipa/raspberrypi/cam_helper.hpp @@ -0,0 +1,102 @@ +/* SPDX-License-Identifier: BSD-2-Clause */ +/* + * Copyright (C) 2019, Raspberry Pi (Trading) Limited + * + * cam_helper.hpp - helper class providing camera information + */ +#pragma once + +#include <string> + +#include "camera_mode.h" +#include "md_parser.hpp" + +#include "v4l2_videodevice.h" + +namespace RPi { + +// The CamHelper class provides a number of facilities that anyone trying +// trying to drive a camera will need to know, but which are not provided by +// by the standard driver framework. Specifically, it provides: +// +// A "CameraMode" structure to describe extra information about the chosen +// mode of the driver. For example, how it is cropped from the full sensor +// area, how it is scaled, whether pixels are averaged compared to the full +// resolution. +// +// The ability to convert between number of lines of exposure and actual +// exposure time, and to convert between the sensor's gain codes and actual +// gains. +// +// A method to return the number of frames of delay between updating exposure +// and analogue gain and the changes taking effect. For many sensors these +// take the values 2 and 1 respectively, but sensors that are different will +// need to over-ride the default method provided. +// +// A method to query if the sensor outputs embedded data that can be parsed. +// +// A parser to parse the metadata buffers provided by some sensors (for +// example, the imx219 does; the ov5647 doesn't). This allows us to know for +// sure the exposure and gain of the frame we're looking at. CamHelper +// provides methods for converting analogue gains to and from the sensor's +// native gain codes. +// +// Finally, a set of methods that determine how to handle the vagaries of +// different camera modules on start-up or when switching modes. Some +// modules may produce one or more frames that are not yet correctly exposed, +// or where the metadata may be suspect. We have the following methods: +// HideFramesStartup(): Tell the pipeline handler not to return this many +// frames at start-up. This can also be used to hide initial frames +// while the AGC and other algorithms are sorting themselves out. +// HideFramesModeSwitch(): Tell the pipeline handler not to return this +// many frames after a mode switch (other than start-up). Some sensors +// may produce innvalid frames after a mode switch; others may not. +// MistrustFramesStartup(): At start-up a sensor may return frames for +// which we should not run any control algorithms (for example, metadata +// may be invalid). +// MistrustFramesModeSwitch(): The number of frames, after a mode switch +// (other than start-up), for which control algorithms should not run +// (for example, metadata may be unreliable). + +// Bitfield to represent the default orientation of the camera. +typedef int CamTransform; +static constexpr CamTransform CamTransform_IDENTITY = 0; +static constexpr CamTransform CamTransform_HFLIP = 1; +static constexpr CamTransform CamTransform_VFLIP = 2; + +class CamHelper +{ +public: + static CamHelper *Create(std::string const &cam_name); + CamHelper(MdParser *parser); + virtual ~CamHelper(); + void SetCameraMode(const CameraMode &mode); + MdParser &Parser() const { return *parser_; } + uint32_t ExposureLines(double exposure_us) const; + double Exposure(uint32_t exposure_lines) const; // in us + virtual uint32_t GainCode(double gain) const = 0; + virtual double Gain(uint32_t gain_code) const = 0; + virtual void GetDelays(int &exposure_delay, int &gain_delay) const; + virtual bool SensorEmbeddedDataPresent() const; + virtual unsigned int HideFramesStartup() const; + virtual unsigned int HideFramesModeSwitch() const; + virtual unsigned int MistrustFramesStartup() const; + virtual unsigned int MistrustFramesModeSwitch() const; + virtual CamTransform GetOrientation() const; +protected: + MdParser *parser_; + CameraMode mode_; + bool initialized_; +}; + +// This is for registering camera helpers with the system, so that the +// CamHelper::Create function picks them up automatically. + +typedef CamHelper *(*CamHelperCreateFunc)(); +struct RegisterCamHelper +{ + RegisterCamHelper(char const *cam_name, + CamHelperCreateFunc create_func); +}; + +} // namespace RPi |