如果根据您的问题，您只想检测带水印的图像，您可以使用以下算法：

If according to your question, you just want to detect the images that are watermarked, you can use the following algorithm:

• 提取水印图像样本扫描水印图像


• 逐个像素地存储数组中的第一个像素。逐个像素地扫描每个


• 图像并存储在一个数组中。每当来自被扫描图像的行矩阵


• 包含


• 相同顺序的数组元素时，它很可能是匹配。

• Extract a sample of the watermarking image Scan the watermark image
• pixel by pixel and store the first pixels in an array. Scan each
• image pixel by pixel and store in an array. Whenever a row matrix
• from the image being scanned contains elements of the array in the
• same order, it's most likely a match.

代码可能是这样的：

$no_of_pixels = what_you_got;
$matched = 0;
$thumbpixels = array();
$wmark = imagecreatefrompng("watermark.png");
list($width, $height) =  getimagesize("watermark.png");
$tesimage = imagecreatefrompng("test.png");
for($h = 0; $h < $height; $h++){    
    for($w = 0; $w < $width; $w++){
        if(imagecolorsforindex($testimage, imagecolorat($testimage, $w, $h)) == $thumbpixels[0]){
            while($thumbpixels[$i++] === imagecolorsforindex($tesimage, imagecolorat($wmark, $w, $h)) && $no_of_pixels != $matched){
                $matched++;
            }
            if($matched == $no_of_pixels) echo "Voila, we found it!";
        }
    }
}

编辑

只看到你的缩略图示例。如果您只想检测文字，可以尝试 tesseract-ocr 或 PhpOCR 。

您也可以考虑 PHPSane