Selects a threshold for each pixel based on a range of intensity

# Imagick::adaptiveThresholdImage

(PECL imagick 2, PECL imagick 3)

Imagick::adaptiveThresholdImage — Selects a threshold for each pixel based on a range of intensity

### 说明

public function Imagick::adaptiveThresholdImage(int `$width`, int `$height`, int `$offset`): bool

Selects an individual threshold for each pixel based on the range of intensity values in its local neighborhood. This allows for thresholding of an image whose global intensity histogram doesn't contain distinctive peaks.

### 参数

`width`

  Width of the local neighborhood.

`height`

  Height of the local neighborhood.

`offset`

  The mean offset

### 返回值

成功时返回 `true`。

### 示例

示例 #1 Imagick::adaptiveThresholdImage()

    <?php
    function adaptiveThresholdImage($imagePath, $width, $height, $adaptiveOffset) {
        $imagick = new \Imagick(realpath($imagePath));
        $adaptiveOffsetQuantum = intval($adaptiveOffset * \Imagick::getQuantum());
        $imagick->adaptiveThresholdImage($width, $height, $adaptiveOffsetQuantum);
        header("Content-Type: image/jpg");
        echo $imagick->getImageBlob();
    }

    ?>

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