how to solve this captcha?

[paulebe]

hello, i have a harder challange, how would i use the library to presegment and actually solve thiscaptcha?

img.debugImage("debugPreprocessed");
img.binarize(190);

[skotz]

I'd start by filtering out the horizontal line with a convolution filter that basically smears things vertically.

var cbl = new CBL({
    preprocess: function(img) {
        img.debugImage("debugPreprocessed");
        img.convolute([ [0, 1, 0],
                        [0, 1, 0],
                        [0, 0, 0] ]);
        img.debugImage("debugPreprocessed");
        img.colorRegions(2, false);
        img.debugImage("debugPreprocessed");
    },
    character_set: "ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890",
    blob_min_pixels: 5,
    blob_max_pixels: 100,
    pattern_width: 16,
    pattern_height: 16,
    pattern_maintain_ratio: true,
    allow_console_log: true,
    perceptive_colorspace: true,
    blob_debug: "debugSegmented",
    model_loaded: function() {
        document.getElementById("aSolve").style.display = "inline-block";
    }
});
cbl.train("1NKM4J.png");

It's not perfect, but it's a good start.

[paulebe]

@skotz Thank You!!

[paulebe]

and for this type of captcha with inverse color format above png just like this ...

[skotz]

You could try first inverting the image and then running the same filters as before. I just added the invert method, so you'll need to get the latest version of the library for it to work.

preprocess: function(img) {
    img.debugImage("debugPreprocessed");
    img.invert();
    img.debugImage("debugPreprocessed");
    img.convolute([ [0, 1, 0],
                    [0, 1, 0],
                    [0, 0, 0] ]);
    img.debugImage("debugPreprocessed");
    img.colorRegions(2, false);
    img.debugImage("debugPreprocessed");
}

[skotz]

Actually, since there are always 6 characters that are always in the same place with the same horizontal line, you can just grab the characters out of the same place every time. Again, I added a new method to the library to support this. With this method you can get pretty close to 100% accuracy after training.

var cbl = new CBL({
    preprocess: function(img) {
        img.debugImage("debugPreprocessed");
        img.convolute([ [0, 1, 0],
                        [1, 2, 1],
                        [0, 1, 0] ], 1/6);
        img.debugImage("debugPreprocessed");
        img.binarize(128);
        img.debugImage("debugPreprocessed");
        img.invert();
        img.debugImage("debugPreprocessed");
    },
    fixed_blob_locations: [ 
        { x1:  5, y1: 3, x2: 13, y2: 12 },
        { x1: 15, y1: 3, x2: 23, y2: 12 },
        { x1: 25, y1: 3, x2: 33, y2: 12 },
        { x1: 35, y1: 3, x2: 43, y2: 12 },
        { x1: 45, y1: 3, x2: 53, y2: 12 },
        { x1: 55, y1: 3, x2: 63, y2: 12 } 
    ],
    character_set: "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789",
    pattern_width: 9,
    pattern_height: 10,
    allow_console_log: true,
    blob_debug: "debugSegmented",
    model_file: "model.dat"
});

cbl.train("1NKM4J.png");
cbl.train("3WJ671.png");
cbl.train("730CR1.png");

[paulebe]

Thank You!!! for your great help @skotz

[paulebe]

How can i distinguish between these two different captcha, programtically

So that i can apply transformation accordingly

[skotz]

You could write a method to check the pixel at (0, 0) and see whether it's black or white.

[paulebe]

@skotz Thank you

[paulebe]

@skotz Thank You for your support. now i able to achieve 99% accuracy for the above captcha

[paulebe]

Does the library has any method to get the pixel value? It's some what difficult to get the pixel value through CANVAS element.
Kindly extend the library to support getPixel method

[skotz]

That's a good idea. I'll mark this thread as an enhancement and add that when I have time.

[paulebe]

Thank you for your response @skotz

[paulebe]

CLOSED

[skotz]

By the way, I've added the method. Now you can get a specific pixel and perform some kind of check to see if it's white, and if it is, invert the image.

if (img.getPixel(0, 0).r == 255) {
    img.invert();
}