{IDF_TARGET_NAME} includes an Image Signal Processor (ISP), which is a feature pipeline that consists of many image processing algorithms. ISP receives image data from the DVP camera or MIPI-CSI camera, or system memory, and writes the processed image data to the system memory through DMA. ISP shall work with other modules to read and write data, it can not work alone.
- MIPI-CSI: Camera serial interface, a high-speed serial interface for cameras compliant with MIPI specifications
- DVP: Digital video parallel interface, generally composed of vsync, hsync, de, and data signals
- RAW: Unprocessed data directly output from an image sensor, typically divided into R, Gr, Gb, and B four channels classified into RAW8, RAW10, RAW12, etc., based on bit width
- RGB: Colored image format composed of red, green, and blue colors classified into RGB888, RGB565, etc., based on the bit width of each color
- YUV: Colored image format composed of luminance and chrominance classified into YUV444, YUV422, YUV420, etc., based on the data arrangement
-`Resource Allocation <#isp-resource-allocation>`__ - covers how to allocate ISP resources with properly set of configurations. It also covers how to recycle the resources when they finished working.
-`Enable and disable ISP processor <#isp-enable-disable>`__ - covers how to enable and disable an ISP processor.
ISP driver requires the configuration that specified by :cpp:type:`esp_isp_processor_cfg_t`.
If the configurations in :cpp:type:`esp_isp_processor_cfg_t` is specified, users can call :cpp:func:`esp_isp_new_processor` to allocate and initialize an ISP processor. This function will return an ISP processor handle if it runs correctly. You can take following code as reference.
ISP auto-focus (AF) driver requires the configuration that specified by :cpp:type:`esp_isp_af_config_t`.
If the configurations in :cpp:type:`esp_isp_af_config_t` is specified, users can call :cpp:func:`esp_isp_new_af_controller` to allocate and initialize an ISP AF processor. This function will return an ISP AF processor handle if it runs correctly. You can take following code as reference.
ISP auto-white-balance (AWB) driver requires the configuration specified by :cpp:type:`esp_isp_awb_config_t`.
If an :cpp:type:`esp_isp_awb_config_t` configuration is specified, you can call :cpp:func:`esp_isp_new_awb_controller` to allocate and initialize an ISP AWB processor. This function will return an ISP AWB processor handle on success. You can take following code as reference.
..code:: c
isp_awb_ctlr_t awb_ctlr = NULL;
uint32_t image_width = 800;
uint32_t image_height = 600;
/* The AWB configuration, please refer to the API comment for how to tune these parameters */
If a previously installed ISP processor is no longer needed, it's recommended to recycle the resource by calling :cpp:func:`esp_isp_del_processor`, so that to release the underlying hardware.
If a previously installed ISP AF processor is no longer needed, it's recommended to recycle the resource by calling :cpp:func:`esp_isp_del_af_controller`, so that to release the underlying hardware.
If a previously installed ISP AWB processor is no longer needed, it's recommended to free the resource by calling :cpp:func:`esp_isp_del_awb_controller`, it will also release the underlying hardware.
Aside from the above oneshot API, the ISP AF driver also provides a way to start AF statistics continuously. Calling :cpp:func:`esp_isp_af_controller_start_continuous_statistics` to start the continuous statistics and :cpp:func:`esp_isp_af_controller_stop_continuous_statistics` to stop it.
Note that if you want to use the continuous statistics, you need to register the :cpp:member:`esp_isp_af_env_detector_evt_cbs_t::on_env_statistics_done` or :cpp:member:`esp_isp_af_env_detector_evt_cbs_t::on_env_change` callback to get the statistics result. See how to register in `Register Event Callbacks <#isp-callback>`__
Before doing ISP AWB, you need to enable the ISP AWB processor first, by calling :cpp:func:`esp_isp_awb_controller_enable`. This function:
* Switches the driver state from **init** to **enable**.
Calling :cpp:func:`esp_isp_awb_controller_disable` does the opposite, that is, put the driver back to the **init** state.
.._isp-awb-statistics:
AWB One-shot and Continuous Statistics
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Calling :cpp:func:`esp_isp_awb_controller_get_oneshot_result` to get oneshot AWB statistics result of white patches. You can take following code as reference.
Aside from the above oneshot API, the ISP AWB driver also provides a way to start AWB statistics continuously. Calling :cpp:func:`esp_isp_awb_controller_start_continuous_statistics` starts the continuous statistics and :cpp:func:`esp_isp_awb_controller_stop_continuous_statistics` stops it.
Note that if you want to use the continuous statistics, you need to register the :cpp:member:`esp_isp_awb_cbs_t::on_statistics_done` callback to get the statistics result. See how to register it in `Register Event Callbacks <#isp-callback>`__
After the ISP AF environment detector starts up, it can generate a specific event dynamically. If you have some functions that should be called when the event happens, please hook your function to the interrupt service routine by calling :cpp:func:`esp_isp_af_env_detector_register_event_callbacks`. All supported event callbacks are listed in :cpp:type:`esp_isp_af_env_detector_evt_cbs_t`:
-:cpp:member:`esp_isp_af_env_detector_evt_cbs_t::on_env_statistics_done` sets a callback function for environment statistics done. As this function is called within the ISR context, you must ensure that the function does not attempt to block (e.g., by making sure that only FreeRTOS APIs with ``ISR`` suffix are called from within the function). The function prototype is declared in :cpp:type:`esp_isp_af_env_detector_callback_t`.
-:cpp:member:`esp_isp_af_env_detector_evt_cbs_t::on_env_change` sets a callback function for environment change. As this function is called within the ISR context, you must ensure that the function does not attempt to block (e.g., by making sure that only FreeRTOS APIs with ``ISR`` suffix are called from within the function). The function prototype is declared in :cpp:type:`esp_isp_af_env_detector_callback_t`.
You can save your own context to :cpp:func:`esp_isp_af_env_detector_register_event_callbacks` as well, via the parameter ``user_data``. The user data will be directly passed to the callback function.
After the ISP AWB controller finished statistics of white patches, it can generate a specific event dynamically. If you want to be informed when the statistics done event takes place, please hook your function to the interrupt service routine by calling :cpp:func:`esp_isp_awb_register_event_callbacks`. All supported event callbacks are listed in :cpp:type:`esp_isp_awb_cbs_t`:
-:cpp:member:`esp_isp_awb_cbs_t::on_statistics_done` sets a callback function when finished statistics of the white patches. As this function is called within the ISR context, you must ensure that the function does not attempt to block (e.g., by making sure that only FreeRTOS APIs with ``ISR`` suffix are called from within the function). The function prototype is declared in :cpp:type:`esp_isp_awb_callback_t`.
You can save your own context via the parameter ``user_data`` of :cpp:func:`esp_isp_awb_register_event_callbacks`. The user data will be directly passed to the callback function.
The factory function :cpp:func:`esp_isp_new_processor`, :cpp:func:`esp_isp_del_processor`, :cpp:func:`esp_isp_new_af_controller`, :cpp:func:`esp_isp_del_af_controller`, :cpp:func:`esp_isp_new_af_env_detector`, and :cpp:func:`esp_isp_del_af_env_detector` are guaranteed to be thread safe by the driver, which means, user can call them from different RTOS tasks without protection by extra locks.
.._isp-kconfig-options:
Kconfig Options
^^^^^^^^^^^^^^^
-:ref:`CONFIG_ISP_ISR_IRAM_SAFE` controls whether the default ISR handler should be masked when the cache is disabled
.._isp-iram-safe:
IRAM Safe
^^^^^^^^^
By default, the ISP interrupt will be deferred when the cache is disabled because of writing or erasing the flash.
There is a Kconfig option :ref:`CONFIG_ISP_ISR_IRAM_SAFE` that:
- Enables the interrupt being serviced even when the cache is disabled
- Places all functions that used by the ISR into IRAM
- Places driver object into DRAM (in case it is mapped to PSRAM by accident)
This allows the interrupt to run while the cache is disabled, but comes at the cost of increased IRAM consumption.
