bmcv_hist_balance

对图像进行直方图均衡化操作，提高图像的对比度。

接口形式：

bm_status_t bmcv_hist_balance(
            bm_handle_t handle,
            bm_device_mem_t input,
            bm_device_mem_t output,
            int H,
            int W);

参数说明：

bm_handle_t handle

输入参数。bm_handle 句柄
bm_device_mem_t input

输入参数。存放输入图像的 device 空间。其大小为 H * W * sizeof(uint8_t)。
bm_device_mem_t output

输出参数。存放输出图像的 device 空间。其大小为 H * W * sizeof(uint8_t)。
int H

输入参数。图像的高。
int W

输入参数。图像的宽。

返回值说明:

BM_SUCCESS: 成功
其他: 失败

注意事项：

数据类型仅支持 uint8_t。
支持的最小图像尺寸为 H = 1, W = 1。
支持的最大图像尺寸为 H = 8192, W = 8192。

示例代码

int H = 1024;
int W = 1024;
uint8_t* input_addr = (uint8_t*)malloc(H * W * sizeof(uint8_t));
uint8_t* output_addr = (uint8_t*)malloc(H * W * sizeof(uint8_t));
bm_handle_t handle;
bm_status_t ret = BM_SUCCESS;
bm_device_mem_t input, output;
int i;

struct timespec tp;
clock_gettime(NULL, &tp);
srand(tp.tv_nsec);

for (i = 0; i < W * H; ++i) {
    input_addr[i] = (uint8_t)rand() % 256;
}

ret = bm_dev_request(&handle, 0);
if (ret != BM_SUCCESS) {
    printf("bm_dev_request failed. ret = %d\n", ret);
    exit(-1);
}

ret = bm_malloc_device_byte(handle, &input, H * W * sizeof(uint8_t));
if (ret != BM_SUCCESS) {
    printf("bm_malloc_device_byte failed. ret = %d\n", ret);
    exit(-1);
}

ret = bm_malloc_device_byte(handle, &output, H * W * sizeof(uint8_t));
if (ret != BM_SUCCESS) {
    printf("bm_malloc_device_byte failed. ret = %d\n", ret);
    exit(-1);
}

ret = bm_memcpy_s2d(handle, input, input_addr);
if (ret != BM_SUCCESS) {
    printf("bm_memcpy_s2d failed. ret = %d\n", ret);
    exit(-1);
}

ret = bmcv_hist_balance(handle, input, output, H, W);
if (ret != BM_SUCCESS) {
    printf("bmcv_hist_balance failed. ret = %d\n", ret);
    exit(-1);
}

ret = bm_memcpy_d2s(handle, output_addr, output);
if (ret != BM_SUCCESS) {
    printf("bm_memcpy_d2s failed. ret = %d\n", ret);
    exit(-1);
}

free(input_addr);
free(output_addr);
bm_free_device(handle, input);
bm_free_device(handle, output);
bm_dev_free(handle);