从节点.js中扫描的图像中评估复选框

回答，我昨天和今天真的很忙。下面是一个示例，用于抓取图像的预定义区域并确定复选框是填充还是空。这只是一个起点，可能会有很大的改进，但如果扫描的图像质量不错，它应该可以工作。

第一步是获取图像的像素。接下来，通过根据模式抓取复选框来获取图像中包含复选框的区域。最后，通过将图像中该区域的平均亮度与未选中框的基线亮度进行比较，评估是否选中了复选框。

我建议使用 get-pixel Node.js 包来获取图像像素。

下面是一个示例，您可以根据需要进行调整：

var get_pixels = require(‘get-pixels’);
var image_uri = 'path_to_image';
get_pixels(image_uri, process_image);
var pattern_width = 800, // Width of your pattern image
    pattern_height = 1100; // Height of your pattern image
// The pattern image doesn't need to be loaded, you just need to use its dimensions to reference the checkbox regions below
// This is only for scaling purposes in the event that the scanned image is of a higher or lower resolution than what you used as a pattern.
var checkboxes = [
    {x1: 10, y1: 10, x2: 30, y2: 30}, // Top left and bottom right corners of the region containing the checkbox
    {x1: 10, y1: 60, x2: 30, y2: 80}
];
// You'll need to get these by running this on an unchecked form and logging out the adjusted_average of the regions
var baseline_average = ??, // The average brightness of an unchecked region
    darkness_tolerance = ??; // The offset below which the box is still considered unchecked
function process_image(err, pixels) {
    if (!err) {
        var regions = get_regions(pixels);
        var checkbox_states = evaluate_regions(regions);
        // Whatever you want to do with the determined states
    }else{
        console.log(err);
        return;
    }
}
function get_regions(pixels) {
    var regions = [], // Array to hold the pixel data from selected regions
        img_width = pixels.shape[0], // Get the width of the image being processed
        img_height = pixels.shape[1], // Get the height
        scale_x = img_width / pattern_width, // Get the width scale difference between pattern and image (for different resolution scans)
        scale_y = img_height / pattern_height; // Get the height scale difference
    for (var i = 0; i < checkboxes.length; i++) {
        var start_x = Math.round(checkboxes[i].x1 * scale_x),
            start_y = Math.round(checkboxes[i].y1 * scale_y),
            end_x = Math.round(checkboxes[i].x2 * scale_x),
            end_y = Math.round(checkboxes[i].y2 * scale_y),
            region = [];
        for (var y = start_y; y <= end_y; y++) {
            for (var x = start_x; y <= end_x; x++) {
                region.push(
                    pixels.get(x, y, 0), // Red channel
                    pixels.get(x, y, 1), // Green channel
                    pixels.get(x, y, 2), // Blue channel
                    pixels.get(x, y, 3) // Alpha channel
                );
            }
        }
        regions.push(region);
    }
    return regions;
}
function evaluate_regions(regions) {
    var states = [];
    for (var i = 0; i < regions.length; i++) {
        var brightest_value = 0,
            darkest_value = 255,
            total = 0;
        for (var j = 0; j < regions[i].length; j+=4) {
            var brightness = (regions[i][j] + regions[i][j + 1] + regions[i][j + 2]) / 3; // Pixel brightness
            if (brightness > brightest_value) brightest_value = brightness;
            if (brightness < darkest_value) darkest_value = brightness;
            total += brightness;
        }
        var adjusted_average = (total / (regions[i].length / 4)) - darkest_value; // Adjust contrast
        var checked = baseline_average - adjusted_average > darkness_tolerance ? true : false;
        states.push(checked);
    }
    return states;
}