Weird behaviour with OV7725 camera
Posted: Sun Mar 17, 2024 2:26 am
Hi all, I'm trying to use a OV7725 camera and an AI-thinker esp32 cam board for a low-light camera project, however I'm having an issue trying to tune the camera sensor settings. If I set the set_gain_ctrl to 1 or don't specify it, the camera pushes ~31 fps in a light environment but drops down to ~4 as soon as it gets into a dark environment. This is kind of to be expected since I assume the camera is increasing gain/exposure/shutter time, however I cannot replicate this behaviour with manual settings. If I set_gain_ctrl to 1 then set set_agc_gain and set_aec_value to their maximums I still get ~30 fps. Really I'm just trying to figure out exactly what set_gain_ctrl does, since it seems like it does more then enable/disable auto gain. I'd like to figure this out since "enabling" auto gain control does result in a significantly better lowlight picture at a massive fps cost, so I want to manually set everything to strike a good balance between low light detail and fps. Here is how I'm setting my camera up:
I took out everything non-related to the camera, if it doesn't compile I might have missed something. I've tried to use get_reg to look at some of the actual register values specified here: https://cdn.sparkfun.com/datasheets/Sen ... OV7725.pdf but I honestly don't know what to make of a lot of that. If anyone might know exactly what set_gain_ctrl affects that would be very helpful.
Code: Select all
#include "esp_camera.h"
#define PWDN_GPIO_NUM 32
#define RESET_GPIO_NUM -1
#define XCLK_GPIO_NUM 0
#define SIOD_GPIO_NUM 26
#define SIOC_GPIO_NUM 27
#define Y9_GPIO_NUM 35
#define Y8_GPIO_NUM 34
#define Y7_GPIO_NUM 39
#define Y6_GPIO_NUM 36
#define Y5_GPIO_NUM 21
#define Y4_GPIO_NUM 19
#define Y3_GPIO_NUM 18
#define Y2_GPIO_NUM 5
#define VSYNC_GPIO_NUM 25
#define HREF_GPIO_NUM 23
#define PCLK_GPIO_NUM 22
double timeInit = 0;
double timeEnd;
double fps;
void setup() {
cameraInit();
Serial.begin(115200);
}
void cameraInit(){
camera_config_t config;
config.ledc_channel = LEDC_CHANNEL_0;
config.ledc_timer = LEDC_TIMER_0;
config.pin_d0 = Y2_GPIO_NUM;
config.pin_d1 = Y3_GPIO_NUM;
config.pin_d2 = Y4_GPIO_NUM;
config.pin_d3 = Y5_GPIO_NUM;
config.pin_d4 = Y6_GPIO_NUM;
config.pin_d5 = Y7_GPIO_NUM;
config.pin_d6 = Y8_GPIO_NUM;
config.pin_d7 = Y9_GPIO_NUM;
config.pin_xclk = XCLK_GPIO_NUM;
config.pin_pclk = PCLK_GPIO_NUM;
config.pin_vsync = VSYNC_GPIO_NUM;
config.pin_href = HREF_GPIO_NUM;
config.pin_sccb_sda = SIOD_GPIO_NUM;
config.pin_sccb_scl = SIOC_GPIO_NUM;
config.pin_pwdn = PWDN_GPIO_NUM;
config.pin_reset = RESET_GPIO_NUM;
config.xclk_freq_hz = 20000000;
config.frame_size = FRAMESIZE_240X240; // datasheet
config.pixel_format = PIXFORMAT_RGB565; // for streaming
config.grab_mode = CAMERA_GRAB_WHEN_EMPTY;
config.fb_location = CAMERA_FB_IN_PSRAM;
config.jpeg_quality = 10;
config.fb_count = 2;
esp_err_t err = esp_camera_init(&config);
if (err != ESP_OK) {
return;
}
sensor_t *s = esp_camera_sensor_get();
s->set_gain_ctrl(s, 1); // auto gain enabled (I think that's what it does)
}
void loop() {
timeInit = millis();
camera_fb_t * fb = esp_camera_fb_get();
esp_camera_fb_return(fb);
timeEnd = (millis() - timeInit) / 1000;
fps = 1 / timeEnd;
Serial.println(fps);
}