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# General Instance Segmentation Pipeline Tutorial
## 1. Introduction to the General Instance Segmentation Pipeline
Instance segmentation is a computer vision task that not only identifies the object categories in an image but also distinguishes the pixels of different instances within the same category, enabling precise segmentation of each object. Instance segmentation can separately label each car, person, or animal in an image, ensuring they are independently processed at the pixel level. For example, in a street scene image containing multiple cars and pedestrians, instance segmentation can clearly separate the contours of each car and person, forming multiple independent region labels. This technology is widely used in autonomous driving, video surveillance, and robotic vision, often relying on deep learning models (such as Mask R-CNN) to achieve efficient pixel classification and instance differentiation through Convolutional Neural Networks (CNNs), providing powerful support for understanding complex scenes.
The General Instance Segmentation Pipeline includes a Object Detection module. If you prioritize model precision, choose a model with higher precision. If you prioritize inference speed, choose a model with faster inference. If you prioritize model storage size, choose a model with a smaller storage size.
| Parameter |
Description |
Type |
Options |
Default |
input |
Data to be predicted, supports multiple input types, required |
Python Var|str|list |
- Python Var: Image data represented by
numpy.ndarray
- str: Local path of an image file or PDF file, such as
/root/data/img.jpg; URL link, such as a network URL of an image file or PDF file: Example; Local directory, which should contain images to be predicted, such as /root/data/ (currently does not support prediction of directories containing PDF files, PDF files need to be specified to specific file paths)
- List: Elements of the list must be of the above types, such as
[numpy.ndarray, numpy.ndarray], ["/root/data/img1.jpg", "/root/data/img2.jpg"], ["/root/data1", "/root/data2"]
|
None |
device |
Pipeline inference device |
str|None |
- CPU: Such as
cpu indicates using CPU for inference;
- GPU: Such as
gpu:0 indicates using the 1st GPU for inference;
- NPU: Such as
npu:0 indicates using the 1st NPU for inference;
- XPU: Such as
xpu:0 indicates using the 1st XPU for inference;
- MLU: Such as
mlu:0 indicates using the 1st MLU for inference;
- DCU: Such as
dcu:0 indicates using the 1st DCU for inference;
- None: If set to
None, the default value initialized by the pipeline will be used. During initialization, it will preferentially use the local GPU 0 device, if not available, the CPU device will be used;
|
None |
threshold |
Low score object filtering threshold for the model |
float|None |
- float: Any floating-point number greater than
0 and less than 1
- None: If set to
None, the default parameter 0.5 of the pipeline will be used as the threshold
|
None |
(3) Process the prediction results. The prediction result for each sample is of type `dict` and supports operations such as printing, saving as an image, and saving as a `json` file:
| Method |
Description |
Parameter |
Type |
Parameter Description |
Default Value |
print() |
Print the result to the terminal |
format_json |
bool |
Whether to format the output content using JSON indentation |
True |
indent |
int |
Specify the indentation level to beautify the output JSON data, making it more readable. Effective only when format_json is True |
4 |
ensure_ascii |
bool |
Control whether non-ASCII characters are escaped to Unicode. When set to True, all non-ASCII characters will be escaped; False retains the original characters. Effective only when format_json is True |
False |
save_to_json() |
Save the result as a json file |
save_path |
str |
Path to save the file. If it is a directory, the saved file name will be consistent with the input file type |
None |
indent |
int |
Specify the indentation level to beautify the output JSON data, making it more readable. Effective only when format_json is True |
4 |
ensure_ascii |
bool |
Control whether non-ASCII characters are escaped to Unicode. When set to True, all non-ASCII characters will be escaped; False retains the original characters. Effective only when format_json is True |
False |
save_to_img() |
Save the result as an image file |
save_path |
str |
Path to save the file. Supports directory or file path |
None |
- Calling the `print()` method will print the result to the terminal. The content printed to the terminal is explained as follows:
- `input_path`: `(str)` Input path of the image to be predicted
- `page_index`: `(Union[int, None])` If the input is a PDF file, it indicates the current page of the PDF; otherwise, it is `None`
- `boxes`: `(list)` Detection box information, each element is a dictionary containing the following fields:
- `cls_id`: `(int)` Class ID
- `label`: `(str)` Class name
- `score`: `(float)` Confidence of the detection box
- `coordinate`: `(list)` Coordinates of the detection box, in the format [xmin, ymin, xmax, ymax]
- `masks`: `...` The actual predicted mask of the instance segmentation model. Due to the large amount of data, it is not convenient to print directly, so it is replaced with `...`. You can save the prediction result as an image using `res.save_to_img` or save it as a json file using `res.save_to_json`.
- Calling the `save_to_json()` method will save the above content to the specified `save_path`. If specified as a directory, the saved path will be `save_path/{your_img_basename}_res.json`. If specified as a file, it will be saved directly to that file. Since json files do not support saving numpy arrays, `numpy.array` types will be converted to lists.
- Calling the `save_to_img()` method will save the visualization result to the specified `save_path`. If specified as a directory, the saved path will be `save_path/{your_img_basename}_res.{your_img_extension}`. If specified as a file, it will be saved directly to that file.
* In addition, you can also obtain the visualized image and prediction results through attributes, as follows:
API Reference
For the main operations provided by the service:
- The HTTP request method is POST.
- Both the request body and response body are JSON data (JSON objects).
- When the request is successfully processed, the response status code is
200, and the attributes of the response body are as follows:
| Name |
Type |
Meaning |
logId |
string |
The UUID of the request. |
errorCode |
integer |
Error code. Fixed at 0. |
errorMsg |
string |
Error description. Fixed at "Success". |
result |
object |
Operation result. |
- When the request is not successfully processed, the attributes of the response body are as follows:
| Name |
Type |
Meaning |
logId |
string |
The UUID of the request. |
errorCode |
integer |
Error code. Same as the response status code. |
errorMsg |
string |
Error description. |
The main operations provided by the service are as follows:
Perform instance segmentation on an image.
POST /instance-segmentation
- The attributes of the request body are as follows:
| Name |
Type |
Meaning |
Required |
image |
string |
The URL of the image file accessible by the server or the Base64 encoded content of the image file. |
Yes |
threshold |
number | null |
Please refer to the description of the threshold parameter of the pipeline object's predict method. |
No |
- When the request is successfully processed, the
result of the response body has the following attributes:
| Name |
Type |
Meaning |
instances |
array |
Information about the location, category, and other details of instances. |
image |
string| null |
The result image of instance segmentation. The image is in JPEG format and encoded using Base64. |
Each element in instances is an object with the following attributes:
| Name |
Type |
Meaning |
bbox |
array |
The location of the instance. The elements in the array are the x-coordinate of the top-left corner, the y-coordinate of the top-left corner, the x-coordinate of the bottom-right corner, and the y-coordinate of the bottom-right corner. |
categoryId |
integer |
The category ID of the instance. |
categoryName |
string |
The label name of the instance category. |
score |
number |
The score of the instance. |
mask |
object |
The segmentation mask of the instance. |
The attributes of mask are as follows:
| Name |
Type |
Meaning |
rleResult |
str |
The run-length encoding result of the mask. |
size |
array |
The shape of the mask. The elements in the array are the height and width of the mask. |
result example is as follows:
{
"instances": [
{
"bbox": [
162.39381408691406,
83.88176727294922,
624.0797119140625,
343.4986877441406
],
"categoryId": 33,
"score": 0.8691174983978271,
"mask": {
"rleResult": "xxxxxx",
"size": [
259,
462
]
}
}
],
"image": "xxxxxx"
}
Multi-Language Service Call Examples
Python
import base64
import requests
API_URL = "http://localhost:8080/instance-segmentation" # Service URL
image_path = "./demo.jpg"
output_image_path = "./out.jpg"
# Encode the local image using Base64
with open(image_path, "rb") as file:
image_bytes = file.read()
image_data = base64.b64encode(image_bytes).decode("ascii")
payload = {"image": image_data} # Base64-encoded file content or image URL
# Call the API
response = requests.post(API_URL, json=payload)
# Process the response data
assert response.status_code == 200
result = response.json()["result"]
with open(output_image_path, "wb") as file:
file.write(base64.b64decode(result["image"]))
print(f"Output image saved at {output_image_path}")
print("\nInstances:")
print(result["instances"])
C++
#include <iostream>
#include "cpp-httplib/httplib.h" // https://github.com/Huiyicc/cpp-httplib
#include "nlohmann/json.hpp" // https://github.com/nlohmann/json
#include "base64.hpp" // https://github.com/tobiaslocker/base64
int main() {
httplib::Client client("localhost:8080");
const std::string imagePath = "./demo.jpg";
const std::string outputImagePath = "./out.jpg";
httplib::Headers headers = {
{"Content-Type", "application/json"}
};
// Encode the local image using Base64
std::ifstream file(imagePath, std::ios::binary | std::ios::ate);
std::streamsize size = file.tellg();
file.seekg(0, std::ios::beg);
std::vector<char> buffer(size);
if (!file.read(buffer.data(), size)) {
std::cerr << "Error reading file." << std::endl;
return 1;
}
std::string bufferStr(reinterpret_cast<const char*>(buffer.data()), buffer.size());
std::string encodedImage = base64::to_base64(bufferStr);
nlohmann::json jsonObj;
jsonObj["image"] = encodedImage;
std::string body = jsonObj.dump();
// Call the API
auto response = client.Post("/instance-segmentation", headers, body, "application/json");
// Process the response data
if (response && response->status == 200) {
nlohmann::json jsonResponse = nlohmann::json::parse(response->body);
auto result = jsonResponse["result"];
encodedImage = result["image"];
std::string decodedString = base64::from_base64(encodedImage);
std::vector<unsigned char> decodedImage(decodedString.begin(), decodedString.end());
std::ofstream outputImage(outputImagePath, std::ios::binary | std::ios::out);
if (outputImage.is_open()) {
outputImage.write(reinterpret_cast<char*>(decodedImage.data()), decodedImage.size());
outputImage.close();
std::cout << "Output image saved at " << outputImagePath << std::endl;
} else {
std::cerr << "Unable to open file for writing: " << outputImagePath << std::endl;
}
auto instances = result["instances"];
std::cout << "\nInstances:" << std::endl;
for (const auto& inst : instances) {
std::cout << inst << std::endl;
}
} else {
std::cout << "Failed to send HTTP request." << std::endl;
return 1;
}
return 0;
}
Java
import okhttp3.*;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.node.ObjectNode;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Base64;
public class Main {
public static void main(String[] args) throws IOException {
String API_URL = "http://localhost:8080/instance-segmentation"; // Service URL
String imagePath = "./demo.jpg"; // Local image
String outputImagePath = "./out.jpg"; // Output image
// Encode the local image to Base64
File file = new File(imagePath);
byte[] fileContent = java.nio.file.Files.readAllBytes(file.toPath());
String imageData = Base64.getEncoder().encodeToString(fileContent);
ObjectMapper objectMapper = new ObjectMapper();
ObjectNode params = objectMapper.createObjectNode();
params.put("image", imageData); // Base64-encoded file content or image URL
// Create an OkHttpClient instance
OkHttpClient client = new OkHttpClient();
MediaType JSON = MediaType.Companion.get("application/json; charset=utf-8");
RequestBody body = RequestBody.Companion.create(params.toString(), JSON);
Request request = new Request.Builder()
.url(API_URL)
.post(body)
.build();
// Call the API and process the response data
try (Response response = client.newCall(request).execute()) {
if (response.isSuccessful()) {
String responseBody = response.body().string();
JsonNode resultNode = objectMapper.readTree(responseBody);
JsonNode result = resultNode.get("result");
String base64Image = result.get("image").asText();
JsonNode instances = result.get("instances");
byte[] imageBytes = Base64.getDecoder().decode(base64Image);
try (FileOutputStream fos = new FileOutputStream(outputImagePath)) {
fos.write(imageBytes);
}
System.out.println("Output image saved at " + outputImagePath);
System.out.println("\nInstances: " + instances.toString());
} else {
System.err.println("Request failed with code: " + response.code());
}
}
}
}
Go
package main
import (
"bytes"
"encoding/base64"
"encoding/json"
"fmt"
"io/ioutil"
"net/http"
)
func main() {
API_URL := "http://localhost:8080/instance-segmentation"
imagePath := "./demo.jpg"
outputImagePath := "./out.jpg"
// Encode the local image in Base64
imageBytes, err := ioutil.ReadFile(imagePath)
if err != nil {
fmt.Println("Error reading image file:", err)
return
}
imageData := base64.StdEncoding.EncodeToString(imageBytes)
payload := map[string]string{"image": imageData} // Base64 encoded file content or image URL
payloadBytes, err := json.Marshal(payload)
if err != nil {
fmt.Println("Error marshaling payload:", err)
return
}
// Call the API
client := &http.Client{}
req, err := http.NewRequest("POST", API_URL, bytes.NewBuffer(payloadBytes))
if err != nil {
fmt.Println("Error creating request:", err)
return
}
res, err := client.Do(req)
if err != nil {
fmt.Println("Error sending request:", err)
return
}
defer res.Body.Close()
// Process the returned data
body, err := ioutil.ReadAll(res.Body)
if err != nil {
fmt.Println("Error reading response body:", err)
return
}
type Response struct {
Result struct {
Image string `json:"image"`
Instances []map[string]interface{} `json:"instances"`
} `json:"result"`
}
var respData Response
err = json.Unmarshal([]byte(string(body)), &respData)
if err != nil {
fmt.Println("Error unmarshaling response body:", err)
return
}
outputImageData, err := base64.StdEncoding.DecodeString(respData.Result.Image)
if err != nil {
fmt.Println("Error decoding base64 image data:", err)
return
}
err = ioutil.WriteFile(outputImagePath, outputImageData, 0644)
if err != nil {
fmt.Println("Error writing image to file:", err)
return
}
fmt.Printf("Image saved at %s.jpg\n", outputImagePath)
fmt.Println("\nInstances:")
for _, inst := range respData.Result.Instances {
fmt.Println(inst)
}
}
C#
using System;
using System.IO;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Threading.Tasks;
using Newtonsoft.Json.Linq;
class Program
{
static readonly string API_URL = "http://localhost:8080/instance-segmentation";
static readonly string imagePath = "./demo.jpg";
static readonly string outputImagePath = "./out.jpg";
static async Task Main(string[] args)
{
var httpClient = new HttpClient();
// Encode the local image using Base64
byte[] imageBytes = File.ReadAllBytes(imagePath);
string image_data = Convert.ToBase64String(imageBytes);
var payload = new JObject{ { "image", image_data } }; // Base64-encoded file content or image URL
var content = new StringContent(payload.ToString(), Encoding.UTF8, "application/json");
// Call the API
HttpResponseMessage response = await httpClient.PostAsync(API_URL, content);
response.EnsureSuccessStatusCode();
// Process the API response data
string responseBody = await response.Content.ReadAsStringAsync();
JObject jsonResponse = JObject.Parse(responseBody);
string base64Image = jsonResponse["result"]["image"].ToString();
byte[] outputImageBytes = Convert.FromBase64String(base64Image);
File.WriteAllBytes(outputImagePath, outputImageBytes);
Console.WriteLine($"Output image saved at {outputImagePath}");
Console.WriteLine("\nInstances:");
Console.WriteLine(jsonResponse["result"]["instances"].ToString());
}
}
Node.js
const axios = require('axios');
const fs = require('fs');
const API_URL = 'http://localhost:8080/instance-segmentation';
const imagePath = './demo.jpg';
const outputImagePath = './out.jpg';
let config = {
method: 'POST',
maxBodyLength: Infinity,
url: API_URL,
data: JSON.stringify({
'image': encodeImageToBase64(imagePath) // Base64-encoded file content or image URL
})
};
// Encode the local image using Base64
function encodeImageToBase64(filePath) {
const bitmap = fs.readFileSync(filePath);
return Buffer.from(bitmap).toString('base64');
}
// Call the API
axios.request(config)
.then((response) => {
// Process the response data
const result = response.data['result'];
const imageBuffer = Buffer.from(result['image'], 'base64');
fs.writeFile(outputImagePath, imageBuffer, (err) => {
if (err) throw err;
console.log(`Output image saved at ${outputImagePath}`);
});
console.log('\nInstances:');
console.log(result['instances']);
})
.catch((error) => {
console.log(error);
});
PHP
<?php
$API_URL = "http://localhost:8080/instance-segmentation"; // Service URL
$image_path = "./demo.jpg";
$output_image_path = "./out.jpg";
// Encode the local image using Base64
$image_data = base64_encode(file_get_contents($image_path));
$payload = array("image" => $image_data); // Base64-encoded file content or image URL
// Call the API
$ch = curl_init($API_URL);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($payload));
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/json'));
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$response = curl_exec($ch);
curl_close($ch);
// Process the response data
$result = json_decode($response, true)['result'];
file_put_contents($output_image_path, base64_decode($result['image']));
echo "Output image saved at " . $output_image_path . "\n";
echo "\nInstances:\n";
print_r($result['instances']);
?>