ESP32_cam access and resize image
Posted: Fri Oct 09, 2020 6:53 am
Hey,
i would like to directly access and scale the images taken by a esp32_cam aithinker. (Full code down below)
The main goal is to have the image in a 2D array with (e.g.) 28x28 pixels. Therefore I save the image into the buffer with
I have declared the format to be PIXFORMAT_GRAYSCALE, and therefore the data shouldn't be converted to jpeg, correct?
When trying to Serial.print() some values with
i do get some values like
I was curious if these were already the grayscale values (between 0 and 255) of each pixel, but the values did neither become 0 nor 255 whenever i covered the whole camera or put a light source close to it.
The questions are:
How do I get the grayscale values from each pixel?
How can I put the values into a 2D array so I can easily Serial.print() the values (to check if things work correctly)?
How can I reduce the size of the image (maybe some code snippets?)
Im not too much into c++, so i would be happy with any advice!
i would like to directly access and scale the images taken by a esp32_cam aithinker. (Full code down below)
The main goal is to have the image in a 2D array with (e.g.) 28x28 pixels. Therefore I save the image into the buffer with
Code: Select all
camera_fb_t * frame = NULL;
frame = esp_camera_fb_get();When trying to Serial.print() some values with
Code: Select all
for (int i =o; i <5; i++){
Serial.println(frame->buf[i]);
}Code: Select all
29
30
32
28
37The questions are:
How do I get the grayscale values from each pixel?
How can I put the values into a 2D array so I can easily Serial.print() the values (to check if things work correctly)?
How can I reduce the size of the image (maybe some code snippets?)
Im not too much into c++, so i would be happy with any advice!
Code: Select all
#define CAMERA_MODEL_AI_THINKER
#include <esp_camera.h>
#include "camera_pins.h"
#define FRAME_SIZE FRAMESIZE_QQVGA
#define WIDTH 160
#define HEIGHT 120
uint16_t img_array [HEIGHT][WIDTH] = { 0 };
bool setup_camera(framesize_t);
void frame_to_array(camera_fb_t * frame);
void print_image_shape(camera_fb_t * frame);
bool capture_image();
void setup() {
Serial.begin(115200);
Serial.println(setup_camera(FRAME_SIZE) ? "OK" : "ERR INIT");
}
void loop() {
if (!capture_image()) {
Serial.println("Failed capture");
delay(2000);
return;
}
//print_features();
delay(3000);
}
bool setup_camera(framesize_t frameSize) {
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_sscb_sda = SIOD_GPIO_NUM;
config.pin_sscb_scl = SIOC_GPIO_NUM;
config.pin_pwdn = PWDN_GPIO_NUM;
config.pin_reset = RESET_GPIO_NUM;
config.xclk_freq_hz = 20000000;
config.pixel_format = PIXFORMAT_GRAYSCALE;
config.frame_size = FRAMESIZE_QQVGA;
config.jpeg_quality = 12;
config.fb_count = 1;
bool ok = esp_camera_init(&config) == ESP_OK;
sensor_t *sensor = esp_camera_sensor_get();
sensor->set_framesize(sensor, frameSize);
return ok;
}
bool capture_image() {
camera_fb_t * frame = NULL;
frame = esp_camera_fb_get();
print_image_shape(frame);
uint8_t ** out = NULL;
size_t* out_len = 0;
bool converted = fmt2bmp(frame->buf, frame->len, frame->width, frame->height, frame->format, out, out_len);
//bool converted = fmt2rgb888(frame->buf, frame->len, frame->format, rgb_buf);
//bool converted = frame2bmp(frame, &buf, &buf_len);
if(!converted){
Serial.println("BMP conversion failed");
return ESP_FAIL;
}
esp_camera_fb_return(frame);
if (!frame)
return false;
return true;
}
void print_image_shape(camera_fb_t * frame){
// print shape of image and total length (=heigth*width)
Serial.print("Width: ");
Serial.print(frame->width);
Serial.print("\tHeigth: ");
Serial.print(frame->height);
Serial.print("\tLength: ");
Serial.println(frame->len);
}