detection problem with big resolution width

[Meach]

Hello,
I am having some trouble using your addons, until today when I tried to use it with a webcam, grabbing at more than 1024xsomething resolution.

I made a post on OF forum, with an image example: http://forum.openframeworks.cc/index.php/topic,12164.0.html

Cheers

[fishkingsin]

someone found this problem from launchpad
and seems have the solution

https://answers.launchpad.net/artoolkitplus/+question/160544

[Meach]

Nice, thanks for that.

I downloaded ARToolKitPlus source code and took a look at paramDistortion.cpp file.
I pasted what I think is the interesting part of this file because I don't have much clue on how to change it.

I see that in floatToFixed and fixedToFloat functions there are some short integer being used and some bitshift operations but I don't really know what to change in there.

Any idea @fishkingsin?

//
//  these functions store 2 values (x & y) in a single 32-bit unsigned integer
//  each value is stored as 11.5 fixed point
//

inline
void floatToFixed(ARFloat nX, ARFloat nY, unsigned int &nFixed) {
    short sx = (short) (nX * 32);
    short sy = (short) (nY * 32);

    unsigned short *ux = (unsigned short*) &sx;
    unsigned short *uy = (unsigned short*) &sy;

    nFixed = (*ux << 16) | *uy;
}

inline
void fixedToFloat(unsigned int nFixed, ARFloat& nX, ARFloat& nY) {
    unsigned short ux = (nFixed >> 16);
    unsigned short uy = (nFixed & 0xffff);

    short *sx = (short*) &ux;
    short *sy = (short*) &uy;

    nX = (*sx) / 32.0f;
    nY = (*sy) / 32.0f;
}

int Tracker::arCameraObserv2Ideal_LUT(Camera* pCam, ARFloat ox, ARFloat oy, ARFloat *ix, ARFloat *iy) {
    if (!undistO2ITable)
        buildUndistO2ITable(pCam);

    int x = (int) ox, y = (int) oy;

    fixedToFloat(undistO2ITable[x + y * arImXsize], *ix, *iy);
    return 0;
}

void Tracker::buildUndistO2ITable(Camera* pCam) {
    int x, y;
    ARFloat cx, cy, ox, oy;
    unsigned int fixed;
    char* cachename = NULL;
    bool loaded = false;

    if (loadCachedUndist) {
        assert(pCam->getFileName() != "");
        cachename = new char[strlen(pCam->getFileName().c_str()) + 5];
        strcpy(cachename, pCam->getFileName().c_str());
        strcat(cachename, ".LUT");
    }

    // we have to take care here when using a memory manager that can not free memory
    // (usually this lookup table should only be built once - unless we change camera resolution)
    //
    if (undistO2ITable)
        delete[] undistO2ITable;

    undistO2ITable = new unsigned int[arImXsize * arImYsize];

    if (loadCachedUndist) {
        if (FILE* fp = fopen(cachename, "rb")) {
            size_t numBytes = fread(undistO2ITable, 1, arImXsize * arImYsize * sizeof(unsigned int), fp);
            fclose(fp);

            if (numBytes == arImXsize * arImYsize * sizeof(unsigned int))
                loaded = true;
        }
    }

    if (!loaded) {
        for (x = 0; x < arImXsize; x++) {
            for (y = 0; y < arImYsize; y++) {
                arCameraObserv2Ideal_std(pCam, (ARFloat) x, (ARFloat) y, &cx, &cy);
                floatToFixed(cx, cy, fixed);
                fixedToFloat(fixed, ox, oy);
                undistO2ITable[x + y * arImXsize] = fixed;
            }
        }

        if (loadCachedUndist)
            if (FILE* fp = fopen(cachename, "wb")) {
                fwrite(undistO2ITable, 1, arImXsize * arImYsize * sizeof(unsigned int), fp);
                fclose(fp);
            }
    }

    delete[] cachename;
}

Thanks

[kalwalt]

I don't notice this bug before... but as i use HD screens with ofxARToolkitPlus addon i'm interested to solve this. But looking at Logitech_Notebook_Pro.cal you see:

ARToolKitPlus_CamCal_Rev02
640 480 330.27758683214108 228.10613100912309 891.32055276878066 888.496623076345940 -0.049480033893318 0.215863227944058 -0.001997733892605 -0.003151872552003 0.0 0.0 10

maybe changing aspect ratio here solve the issue?

[kalwalt]

and maybe it's needed another calibration file?

[Meach]

My plan is to make a new calibration file for the logitech c920, I currently use.
This evening if I have time, I will give it a try using this http://graphics.cs.msu.ru/en/node/909

[kalwalt]

good to know! i haven't a HD cam so i can't help you with this...sorry @Meach !