If the target image has too few recognizable areas (such as white walls or solid color blocks) or overly simple textures, its recognition success rate will significantly decrease. This chapter details CRS's rating mechanism to help you select high-quality AR recognition materials.
We primarily focus on the following two comprehensive metrics, each with a dedicated API interface providing overall ratings:
These metrics rate from an algorithmic perspective, each still assigning a difficulty score from 0 to 4.
Detailed ratings for each target image are available in its details within the database. They can be viewed by obtaining target image properties via API or through EasyAR cloud recognition management.
As shown in the figure, the details page includes the two core comprehensive metrics, and a pentagon displays five detailed metrics.
When building an automated upload backend, it is recommended to call the rating API before formal upload.
- First convert the local target image to Base64 (macOS / Linux), saving the result into image_base64.txt
base64 -i ./target.jpg | tr -d '\n' > image_base64.txt
- Please replace the placeholders with actual parameters and run the curl script
- Your-Server-side-URL → Actual API Host
- Your-Token → Actual API Key Authorization Token
- Your-CRS-AppId → Your appId
curl -X POST "https://<Your-Server-side-URL>/grade/detail" \
-H "Content-Type: application/json" \
-H "Authorization: <YOUR-TOKEN>" \
-d '{
"appId": "<Your-CRS-AppId>",
"image": "'"$(cat image_base64.txt)"'"
}'
Download java sample code
Import project via Maven
Step 1. Open the relevant code file Grade.java
Step 2. Modify global variables, replace authentication parameters from your preparation list
- CRS AppId
- API Key / API Secret
- Server-end URL
- IMAGE_PATH : Target image file to be uploaded
import okhttp3.*;
import org.json.JSONObject;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Base64;
import java.util.HashMap;
import java.util.Map;
public class Grade {
private static final String TARGET_MGMT_URL = "http://cn1.crs.easyar.com:8888";
private static final String CRS_APPID = "--here is your CRS AppId--";
private static final String API_KEY = "--here is your API Key--";
private static final String API_SECRET = "--here is your API Secret--";
private static final String IMAGE_PATH = "test_target_image.jpg";
enum GradeType {
DETAIL,
DETECTION,
TRACKING
}
private static final Map<GradeType, String> GRADE_URL = new HashMap<GradeType, String>(){
{
put(GradeType.DETAIL, "/grade/detail") ;
put(GradeType.DETECTION, "/grade/detection") ;
put(GradeType.TRACKING, "/grade/tracking") ;
}
};
public String grade(Auth auth, String imgPath, GradeType gradeType) throws IOException {
final Path mImagePath = Paths.get(imgPath);
JSONObject params = new JSONObject().put("image", Base64.getEncoder().encodeToString(
Files.readAllBytes(mImagePath)
));
Auth.signParam(params, auth.getAppId(), auth.getApiKey(), auth.getApiSecret());
RequestBody requestBody = FormBody.create(MediaType.parse("application/json; charset=utf-8")
, params.toString());
Request request = new Request.Builder()
.url(auth.getCloudURL() + GRADE_URL.get(gradeType))
.post(requestBody)
.build();
return new OkHttpClient.Builder().build().newCall(request).execute().body().string();
}
public static void main(String[] args) throws IOException {
Auth accessInfo = new Auth(CRS_APPID, API_KEY, API_SECRET, TARGET_MGMT_URL);
System.out.println("================== grade details ==================");
System.out.println(new Grade().grade(accessInfo, IMAGE_PATH, GradeType.DETAIL));
System.out.println("================== grade for detection ==================");
JSONObject gradeResp = new JSONObject(new Grade().grade(accessInfo, IMAGE_PATH, GradeType.DETECTION));
System.out.println("Detection grade: " + gradeResp.getJSONObject(Common.KEY_RESULT).get(Common.KEY_GRADE));
System.out.println("================== grade for tracking =================== ");
gradeResp = new JSONObject(new Grade().grade(accessInfo, IMAGE_PATH, GradeType.TRACKING));
System.out.println("Tracking grade: " + gradeResp.getJSONObject(Common.KEY_RESULT).get(Common.KEY_GRADE));
}
}
Step 3. Run main
Download NodeJS sample code
Step 1. Configure keys file keys.json
- CRS AppId
- API Key / API Secret
{
"appId": "--here is your appId for CRS App Instance for SDK 4--",
"apiKey": "--here is your api key which is create from website and which has crs permission--",
"apiSecret": "--here is your api secret which is create from website--"
}
Step 2. Run, specify the test image, keys file, and Server-end URL
node bin/grade test.jpeg -t <Server-end-URL> -c keys.json
var argv = require('yargs')
.usage('Usage: $0 [image] -t [host] -c [keys]')
.demand(1)
.default('t', 'http://localhost:8888').alias('t', 'host')
.default('c', 'keys.json').alias('c', 'keys')
.help('h').alias('h', 'help')
.epilog('copyright 2015, sightp.com')
.argv;
var fs = require('fs');
var imageFn = argv._[0];
var host = argv.host;
var keys = JSON.parse(fs.readFileSync(argv.keys));
var farmer = require('../farmer')(host, keys);
farmer.getTrackingGrade({
'image': fs.readFileSync(imageFn).toString('base64')
})
.then(function(resp) {
console.log(resp);
})
.fail(function(err) {
console.log(err);
});
Download php sample code
Step 1. Open the entry code demo.php
Step 2. Modify global variables, replace authentication parameters from your preparation list
- CRS AppId
- API Key / API Secret
- Server-end URL
- imageFilePath : path of the target image file to be uploaded
<?php
include 'EasyARClientSdkCRS.php';
$apiKey = 'API Key';
$apiSecret = 'API Secret';
$crsAppId = 'CRS AppId'
$crsCloudUrl = 'https://cn1-crs.easyar.com';
$imageFilePath = '1.jpg'
$sdk = new EasyARClientSdkCRS($apiKey, $apiSecret, $crsAppId, $crsCloudUrl);
$image = base64_encode(file_get_contents($imageFilePath));
$rs = $sdk->detection($image);
if ($rs->statusCode == 0) {
print_r($rs->result->grade);
} else {
print_r($rs);
}
Step 3. Run php demo.php
Create the relevant code file grade.py, modify the global variables, and then run
pip install requests
python grade.py
import time
import hashlib
import requests
import base64
# --- Global Configuration ---
API_KEY = "YOUR_API_KEY"
API_SECRET = "YOUR_API_SECRET"
APP_ID = "YOUR_APP_ID"
HOST = "https://crs-cn1.easyar.com"
IMAGE_PATH = "test.jpg"
def main():
# 1. Read and encode image
with open(IMAGE_PATH, "rb") as f:
image_base64 = base64.b64encode(f.read()).decode('utf-8')
timestamp = str(int(time.time() * 1000))
# 2. Build parameter dictionary (including image)
params = {
'apiKey': API_KEY,
'appId': APP_ID,
'timestamp': timestamp,
'image': image_base64
}
# 3. Sort by key and concatenate
sorted_keys = sorted(params.keys())
builder = "".join([f"{k}{params[k]}" for k in sorted_keys])
builder += API_SECRET
# 4. Generate SHA256 Signature
signature = hashlib.sha256(builder.encode('utf-8')).hexdigest()
# 5. Send POST request
payload = {**params, "signature": signature, "timestamp": int(timestamp)}
response = requests.post(f"{HOST}/grade/detection", json=payload)
print(f"Status: {response.status_code}")
print(f"Response: {response.text}")
if __name__ == "__main__":
main()
Create the relevant code file main.go, modify the global variables, and then run
go run main.go
main.go:
package main
import (
"bytes"
"crypto/sha256"
"encoding/base64"
"encoding/json"
"fmt"
"io"
"net/http"
"os"
"sort"
"strconv"
"time"
)
var (
ApiKey = "YOUR_API_KEY"
ApiSecret = "YOUR_API_SECRET"
AppId = "YOUR_APP_ID"
Host = "https://crs-cn1.easyar.com"
ImagePath = "test.jpg"
)
func main() {
fileData, _ := os.ReadFile(ImagePath)
imgBase64 := base64.StdEncoding.EncodeToString(fileData)
tsInt := time.Now().UnixNano() / 1e6
tsStr := strconv.FormatInt(tsInt, 10)
params := map[string]string{
"apiKey": ApiKey,
"appId": AppId,
"timestamp": tsStr,
"image": imgBase64,
}
keys := make([]string, 0, len(params))
for k := range params { keys = append(keys, k) }
sort.Strings(keys)
var builder bytes.Buffer
for _, k := range keys {
builder.WriteString(k)
builder.WriteString(params[k])
}
builder.WriteString(ApiSecret)
signature := fmt.Sprintf("%x", sha256.Sum256(builder.Bytes()))
payload := map[string]interface{}{
"image": imgBase64,
"apiKey": ApiKey,
"appId": AppId,
"timestamp": tsInt,
"signature": signature,
}
jsonBytes, _ := json.Marshal(payload)
resp, _ := http.Post(Host+"/grade/detection", "application/json", bytes.NewBuffer(jsonBytes))
defer resp.Body.Close()
body, _ := io.ReadAll(resp.Body)
fmt.Printf("Response: %s\n", string(body))
}
Add reqwest, tokio, sha2, hex dependencies in Cargo.toml. Execute cargo run.
use sha2::{Sha256, Digest};
use std::collections::BTreeMap;
use std::time::{SystemTime, UNIX_EPOCH};
use base64::{Engine as _, engine::general_purpose};
const API_KEY: &str = "YOUR_API_KEY";
const API_SECRET: &str = "YOUR_API_SECRET";
const APP_ID: &str = "YOUR_APP_ID";
const HOST: &str = "https://crs-cn1.easyar.com";
const IMAGE_PATH: &str = "test.jpg";
#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
let img_bytes = std::fs::read(IMAGE_PATH)?;
let img_b64 = general_purpose::STANDARD.encode(img_bytes);
let ts_raw = SystemTime::now().duration_since(UNIX_EPOCH)?.as_millis();
let ts_str = ts_raw.to_string();
// 1. Collect params in BTreeMap for automatic sorting
let mut params = BTreeMap::new();
params.insert("apiKey", API_KEY);
params.insert("appId", APP_ID);
params.insert("timestamp", &ts_str);
params.insert("image", &img_b64);
// 2. Build sign string
let mut builder = String::new();
for (k, v) in ¶ms {
builder.push_str(k);
builder.push_str(v);
}
builder.push_str(API_SECRET);
// 3. Hash
let mut hasher = Sha256::new();
hasher.update(builder.as_bytes());
let signature = hex::encode(hasher.finalize());
let mut body = serde_json::Map::new();
body.insert("image".into(), img_b64.into());
body.insert("apiKey".into(), API_KEY.into());
body.insert("appId".into(), APP_ID.into());
body.insert("timestamp".into(), ts_raw.into());
body.insert("signature".into(), signature.into());
let client = reqwest::Client::new();
let res = client.post(format!("{}/grade/detection", HOST))
.json(&body)
.send()
.await?;
println!("Response: {}", res.text().await?);
Ok(())
}
Create a .NET console project.
dotnet new console
dotnet run
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Net.Http;
using System.Text.Json;
class Program {
static string API_KEY = "YOUR_API_KEY";
static string API_SECRET = "YOUR_API_SECRET";
static string APP_ID = "YOUR_APP_ID";
static string HOST = "https://crs-cn1.easyar.com";
static string IMAGE_PATH = "test.jpg";
static async System.Threading.Tasks.Task Main() {
string timestamp = DateTimeOffset.Now.ToUnixTimeMilliseconds().ToString();
string imageBase64 = Convert.ToBase64String(File.ReadAllBytes(IMAGE_PATH));
// 1. Prepare data for signing
var data = new SortedDictionary<string, string> {
{ "apiKey", API_KEY },
{ "appId", APP_ID },
{ "timestamp", timestamp },
{ "image", imageBase64 }
};
// 2. Concatenate keys and values
StringBuilder sb = new StringBuilder();
foreach (var pair in data) sb.Append(pair.Key).Append(pair.Value);
sb.Append(API_SECRET);
string signature = Sha256(sb.ToString());
// 3. Construct JSON body
var body = new {
image = imageBase64,
apiKey = API_KEY,
appId = APP_ID,
timestamp = long.Parse(timestamp),
signature = signature
};
using var client = new HttpClient();
var content = new StringContent(JsonSerializer.Serialize(body), Encoding.UTF8, "application/json");
var response = await client.PostAsync($"{HOST}/grade/detection", content);
Console.WriteLine($"Response: {await response.Content.ReadAsStringAsync()}");
}
static string Sha256(string str) {
byte[] bytes = SHA256.HashData(Encoding.UTF8.GetBytes(str));
return BitConverter.ToString(bytes).Replace("-", "").ToLower();
}
}
- Runtime environment
- Unity 2020 LTS or above
- Scripting Backend: Mono or IL2CPP
- API Compatibility Level: .NET Standard 2.1 (recommended)
Step 1: Prepare image files
- Create directories in the Unity project:
Assets/
└── StreamingAssets/
| └── target.jpg
└── Scripts/
└── GrageImage.cs
- According to the Assets directory name
- Create the script GrageImage.cs and copy the example code below
- Prepare an image target test picture
using System;
using System.IO;
using System.Text;
using UnityEngine;
using UnityEngine.Networking;
using System.Collections;
public class GrageImage : MonoBehaviour
{
[Header("Config")]
public string apiUrl = "https://Your-Server-end-URL" + "/grade/detection";
public string authorizationToken = "YOUR API KEY AUTH TOKEN";
public string imageFilePath = "target.jpg"; // StreamingAssets
public string crsAppId = "<Your-CRS-AppId>";
private void Start()
{
StartCoroutine(Grade());
}
private IEnumerator Grade()
{
// Read image file (Unity StreamingAssets)
string fullPath = Path.Combine(Application.streamingAssetsPath, imageFilePath);
if (!File.Exists(fullPath))
{
Debug.LogError($"Image file not found: {fullPath}");
yield break;
}
byte[] imageBytes = File.ReadAllBytes(fullPath);
string imageBase64 = Convert.ToBase64String(imageBytes);
TargetRequestBody body = new TargetRequestBody
{
appId = crsAppId,
image = imageBase64,
};
string json = JsonUtility.ToJson(body);
// UnityWebRequest
UnityWebRequest request = new UnityWebRequest(apiUrl, "POST");
byte[] jsonBytes = Encoding.UTF8.GetBytes(json);
request.uploadHandler = new UploadHandlerRaw(jsonBytes);
request.downloadHandler = new DownloadHandlerBuffer();
request.SetRequestHeader("Content-Type", "application/json");
request.SetRequestHeader("Authorization", authorizationToken);
yield return request.SendWebRequest();
if (request.result == UnityWebRequest.Result.Success)
{
Debug.Log("Grade detail success:");
Debug.Log(request.downloadHandler.text);
}
else
{
Debug.LogError("Grade detail failed:");
Debug.LogError(request.error);
Debug.LogError(request.downloadHandler.text);
}
}
[Serializable]
private class TargetRequestBody
{
public string appId;
public string image;
}
}
- In Unity Editor:
- Create an empty GameObject
- Name it GradeImage
- Drag the GrageImage script onto this object
Step 3: Configure parameters (inspector)
Modify in the inspector panel. Adjust according to data from the preparation checklist.
- API URL
- Authorization Token
- Image file path: Default target.jpg
- CRS AppId
Only need to modify these four items to run, input the parameters prepared in the checklist
Step 4: Run
- Click Play
- Check results in the console:
- Success: Returns JSON (result contains object)
- Failure: HTTP/error message
