• 中文
  • 3.8.1

    • Warp Perspective

    透视变换是按照物体成像投影规律进行变换，即将物体重新投影到新的成像平面，常用于视觉畸变校正。

    算子效果

    输入图像参数输出图像
    imagekernel=[0.90.0515.00.050.915.00.00010.00011.1]\begin{aligned}kernel = \begin{bmatrix}0.9 & 0.05 & 15.0 \\ 0.05 & 0.9 & 15.0 \\ 0.0001 & 0.0001 & 1.1 \end{bmatrix}\end{aligned}
    interpolation = HB_VP_INTER_LINEAR
    isInverse = 1    		image

    原理

    算子通过大小为3X3的转换矩阵参数，将输入图片按照透视的形式进行映射，映射关系如下：

    dst(x,y)=src(M11x+M12y+M13M31x+M32y+M33,M21x+M22y+M23M31x+M32y+M33)dst(x,y)=src(\frac{M_{11} x+M_{12} y+M_{13}}{M_{31}x+M_{32}y+M_{33}},\frac{M_{21}x+M_{22}y+M_{23}}{M_{31}x+M_{32}y+M_{33}})

    其中，dstdst 为输出图片，srcsrc 为输入图片，MM 为3X3的转换矩阵。

    API接口

    int32_t hbVPWarpPerspective(hbUCPTaskHandle_t *taskHandle,
                            hbVPImage *dstImg,
                            hbVPImage const *srcImg,
                            hbVPPerspectiveParam const *perspectiveParam);

    详细接口信息请查看 hbVPWarpPerspective 。

    使用方法

    // Include the header
#include "hobot/hb_ucp.h"
#include "hobot/vp/hb_vp.h"
#include "hobot/vp/hb_vp_warp_perspective.h"

// init Image, allocate memory for image data
hbUCPSysMem src_mem;
hbUCPMallocCached(&src_mem, src_stride * src_height, 0);
hbVPImage src_img{HB_VP_IMAGE_FORMAT_Y,
                  HB_VP_IMAGE_TYPE_U8C1,
                  src_width,
                  src_height,
                  src_width,
                  src_mem.virAddr,
                  src_mem.phyAddr,
                  nullptr,
                  0,
                  0};

hbUCPSysMem dst_mem;
hbUCPMallocCached(&dst_mem, dst_stride * dst_height, 0);
hbVPImage dst_img{HB_VP_IMAGE_FORMAT_Y,
                  HB_VP_IMAGE_TYPE_U8C1,
                  dst_width,
                  dst_height,
                  dst_stride,
                  dst_mem.virAddr,
                  dst_mem.phyAddr,
                  nullptr,
                  0,
                  0};

// init param
hbVPPerspectiveParam vp_param;
vp_param.transformMatrix[9] = {0};
vp_param.interpolation = HB_VP_INTER_LINEAR;
vp_param.isInverse = 1;

// init task handle and schedule param
hbUCPTaskHandle_t task_handle{nullptr};
hbUCPSchedParam sched_param;
HB_UCP_INITIALIZE_SCHED_PARAM(&sched_param);
sched_param.backend = HB_UCP_DSP_CORE_0;

// create task
hbVPWarpPerspective(&task_handle, &dst_img, &src_img, &vp_param);

// submit task
hbUCPSubmitTask(task_handle, &sched_param);

// wait for task done 
hbUCPWaitTaskDone(task_handle, 0);

// release task handle
hbUCPReleaseTask(task_handle);

// release memory
hbUCPFree(&src_mem);
hbUCPFree(&dst_mem);