Issue visualizing QQVGA with OV7670 camera module

[gimmy987]

Hi,

I have recently started prototyping on Arduino Nano 33 BLE Sense Board to grab camera frames from the OV7670 camera module. I successfully managed to run the pre-built example available on Arduino Nano with QVGA image resolution (320x240) but when I try using the QQVGA one, the output image has some artifacts (test_qvga.png
)

Below, I report the code used to obtain QQVGA images from the camera module:

#include <Arduino_OV767X.h>

uint8_t pixels[160 * 120 * 2]; 

void setup() {
  Serial.begin(115600);
  while (!Serial);

  Serial.println("OV767X Camera Capture");
  Serial.println();

  if (!Camera.begin(QQVGA, RGB565, 1)) {
    Serial.println("Failed to initialize camera!");
    while (1);
  }

  Serial.println("Camera settings:");
  Serial.print("\twidth = ");
  Serial.println(Camera.width());
  Serial.print("\theight = ");
  Serial.println(Camera.height());
  Serial.print("\tbits per pixel = ");
  Serial.println(Camera.bitsPerPixel());
  Serial.println();

  //Camera.testPattern();

  Serial.println("Press the button to read a frame ...");
  Serial.println();
}

void loop() {
    Serial.println("Reading frame");
    Serial.println();
    
    Camera.readFrame(pixels);    
    
    int numPixels = Camera.width() * Camera.height();

    for (int i = 0; i < numPixels * 2; i+=2) {
      //uint16_t p = pixels[i];
      uint16_t p = (pixels[i] << 8) | pixels[i+1];

      uint8_t r = ((p >> 11) & 0x1f) << 3;
      uint8_t g = ((p >> 5) & 0x3f) << 2;
      uint8_t b = ((p >> 0) & 0x1f) << 3;
  
      Serial.println(r);
      Serial.println(g);
      Serial.println(b);
     }
    delay(1000);
}

Do you have any ideas what it could be wrong?

Many thanks in advance,
Gian Marco