Forums - fcvGeomHomographyEvaluatef32 functuion didn't work

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fcvGeomHomographyEvaluatef32 functuion didn't work
Join Date: 14 Oct 21
Posts: 2
Posted: Fri, 2021-12-24 00:04

Hi all,


I'm working with Fastcv and I need to use fcvGeomHomographyEvaluatef32 function and fcvCorrespondences structure, but I have met a problem that the function didn't work in any ways.


I can create a fcvCorrespondences structure as mentioned in the web, and I sucessefully run the similar function of fcvGeomHomographyFitf32, getting the right homography with the Correspondences. But when I use the same Correspondences to run the function of fcvGeomHomographyEvaluatef32, it fails every time with no error shown in the command line (Win10). The result of  numinliers    is 0 all the time even I choose a very high value of maxsqerr and the value of homography is not written. I have set the memory space for inliers and errinliers in advance.



Can someone help me with this problem? 

Thanks in advance!



PS: this is the code I'm using.


fcvCorrespondences corrs;

float *fromRe = (float*)malloc((num*3)*sizeof(float));
uint16_t *indicesRe = (uint16_t*)malloc(num*sizeof(uint16_t));
float *__restrict homography = (float*)malloc(9*sizeof(float));

uint16_t *__restrict inliers = (uint16_t*)malloc(num*sizeof(uint16_t));
float *__restrict errinliers = (float*)malloc(num*sizeof(float));
int32_t *numinliers = (int32_t*)malloc(sizeof(int32_t));
float maxsqerr = 20;


    fromRe -= num*3;
    xy1 -= num*2;
    indicesRe -= num;

    corrs.from = fromRe;
    corrs.fromStride = 3; = xy2;
    corrs.toStride = 2;
    corrs.numCorrespondences = (uint32_t)num;
    corrs.indices = indicesRe;
    corrs.numIndices = num;

/*    void (*fcvGeomHomographyFitf32)(fcvCorrespondences*__restrict, float*__restrict);
    fcvGeomHomographyFitf32 = dlsym(obj, "fcvGeomHomographyFitf32");

    fcvGeomHomographyFitf32(&corrs, homography);*/

/*    int (*fcvGeomHomographyEvaluatef32)(fcvCorrespondences*__restrict, float*__restrict, float, uint16_t*__restrict, int32_t*);
    fcvGeomHomographyEvaluatef32 = dlsym(obj, "fcvGeomHomographyEvaluatef32");

    fcvGeomHomographyEvaluatef32(&corrs, homography, maxsqerr, inliers, numinliers);*/

    int (*fcvGeomHomographyEvaluatef32_v2)(fcvCorrespondences*__restrict, float*__restrict, float, uint16_t*__restrict, float*__restrict, int32_t*);
    fcvGeomHomographyEvaluatef32_v2 = dlsym(obj, "fcvGeomHomographyEvaluatef32_v2");

    fcvGeomHomographyEvaluatef32_v2(&corrs, homography, maxsqerr, inliers, errinliers, numinliers);


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Join Date: 6 Dec 21
Posts: 9
Posted: Wed, 2022-01-05 18:58

Hi Qinyun,

I will test your code in my device and then back to you.



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Join Date: 6 Dec 21
Posts: 9
Posted: Tue, 2022-01-25 22:13

Hi Qinyun,

I got the same result with you, checking with fastcv team to fix it.

will keep update to you.




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