hi_mpi_vpc_equalize_hist

Applicability

Product	Supported
Atlas A3 training products/Atlas A3 inference products	√
Atlas A2 training products/Atlas A2 inference products	√
Atlas 200I/500 A2 inference products	√
Atlas inference products	√
Atlas training products	☓

Description

Remaps a specified pixel value of a specified component in the input image to another pixel value to form the output image, which is usually used for image enhancement. The purpose is to increase the contrast and definition of an image. This API is asynchronous.

Prototype

hi_s32 hi_mpi_vpc_equalize_hist(hi_vpc_chn chn, const hi_vpc_pic_info* source_pic, hi_vpc_pic_info *dest_pic, const hi_vpc_lut_remap *lut_remap, hi_u32 *task_id, hi_s32 milli_sec)

Parameters

Parameter	Input/Output	Description
chn	Input	Channel ID for image processing. Atlas A3 training products/Atlas A3 inference products: The value range of this parameter is [0, 256). The maximum number of channels is 256. Atlas A2 training products/Atlas A2 inference products: The value range of this parameter is [0, 256). The maximum number of channels is 256. Atlas 200I/500 A2 inference products: The value range of this parameter is [0, 128). The maximum number of channels is 128. Atlas inference products: The value range of this parameter is [0, 256). The maximum number of channels is 256.
source_pic	Input	Pointer to the input image information.
dest_pic	Input	Pointer to the destination image information.
lut_remap	Input	Pointer to the image LUT remapping configuration. lut_remap is a 768-byte configuration array for hardware-based pixel remapping.
task_id	Output	Pointer to the task ID, which is used to identify a task.
milli_sec	Input	Timeout interval (ms): –1: blocking mode 0: non-blocking mode > 0: timeout interval (timeout mode). The timeout interval varies with the operating system. The deviation is generally within a time slice of an operating system. For example, if the time slice of an operating system is 4 ms and the value of milli_sec is set to 1, the actual timeout interval ranges from 1 ms to 5 ms. When the CPU load is high, the timeout interval may fluctuate.

Returns

0: success
Other values: failure. For details, see VPC Return Codes.

Restrictions

The input image resolution must be in the range of [10 × 6, 4096 × 4096].

For input images, the following enum values of hi_pixel_format are supported:

HI_PIXEL_FORMAT_YUV_400 = 0,              // YUV400 8bit
HI_PIXEL_FORMAT_YUV_SEMIPLANAR_420 = 1,   // YUV420SP NV12 8bit   
HI_PIXEL_FORMAT_YVU_SEMIPLANAR_420 = 2,   // YUV420SP NV21 8bit 
HI_PIXEL_FORMAT_YUV_SEMIPLANAR_422 = 3,   // YUV422SP 8bit
HI_PIXEL_FORMAT_YVU_SEMIPLANAR_422 = 4,   // YVU422SP 8bit
HI_PIXEL_FORMAT_YUV_PACKED_444 = 11,      // YUV444P 8bit
HI_PIXEL_FORMAT_RGB_888 = 12,             // RGB888
HI_PIXEL_FORMAT_BGR_888 = 13,             // BGR888

The destination image has the same format as the source image.
For details about the restrictions on the width and height alignment, buffer size, and image format, see Restrictions on Image Formats, Width and Height Alignment, and Buffers.

Parent topic: Vision Preprocessing Core (VPC)