/green/image/scan - Content Moderation - Alibaba Cloud Documentation Center

Submits optical character recognition (OCR) tasks and obtains OCR results in real time. You can call this operation to submit the OCR tasks to detect and obtain text in images.

Description

Operation: /green/image/scan

You can call this operation to submit OCR tasks and obtain OCR results in real time. For more information about how to construct an HTTP request, see Request syntax. You can also select an existing HTTP request. For more information, see SDK overview.

Billing method:
You are charged for calling this operation. For more information about the billing methods, see Content Moderation Pricing.
Response timeout:
The maximum response time that is allowed for a synchronous moderation request is 6 seconds. If the moderation is not completed within 6 seconds, a timeout error is returned. If you do not need to obtain moderation results in real time, you can send asynchronous moderation requests. In most cases, we recommend that you send synchronous moderation requests because synchronous moderation operations are easier to call. We recommend that you set the timeout period to 6 seconds for calling synchronous moderation operations.
Returned results:
In general, moderation results are returned within 1 second after you send a synchronous moderation request. The time may increase in special scenarios where a large number of requests are to be processed in the system, the size of images is large, or the images contain a large number of words. The speed of OCR is inversely proportional to the number of words in images. If the images to be moderated contain a large number of words, we recommend that you send asynchronous moderation requests.
Limits on images:
- The URLs of images must be HTTP or HTTPS URLs.
- The images must be in the PNG, JPG, JPEG, BMP, GIF, or WEBP format.
- An image can be up to 20 MB in size. The limit for the image size is applicable to both synchronous and asynchronous moderation operations.
- The duration for downloading an image is limited to 3 seconds. If an image fails to be downloaded within 3 seconds, a timeout error is returned.
- We recommend that you submit images of at least 256 × 256 pixels to ensure the moderation effects.
- The response time of an operation for moderating images varies based on the duration for downloading these images. Make sure that you use a stable and reliable storage service to store the images to be moderated. We recommend that you use Object Storage Service (OSS) or Content Delivery Network (CDN).

QPS limit

You can call this operation up to 10 times per second per account. If the number of calls per second exceeds the limit, throttling is triggered. As a result, your business may be affected. We recommend that you take note of the limit when you call this operation.

Request parameters


Parameter	Type	Required	Example	Description
bizType	String	No	default	The business scenario. You can create a business scenario in the Content Moderation console. For more information, see Customize policies for machine-assisted moderation.
scenes	StringArray	Yes	["ocr"]	The moderation scenario. Set the value to ocr.
tasks	JSONArray	Yes		The list of objects that you want to moderate. The JSON array can contain one or more elements. Each element is a structure. The JSON array can contain up to 100 elements. In other words, you can submit up to 100 moderation objects at a time. To submit 100 moderation objects at a time, you must raise the relevant concurrency limit to a number greater than 100. For more information about the structure, see task.

Table 1. task
Parameter	Type	Required	Example	Description
dataId	String	No	test_data_xxxx	The data ID. Make sure that each ID is unique in a request.
url	String	Yes	https://aliyundoc.com/test_image_xxxx.png	The HTTP or HTTPS URL that can be accessed over the Internet. The URL is up to 2,048 characters in length.
interval	Integer	No	2	The interval between two frames that are consecutively captured. This parameter is dedicated for GIF or long image moderation. A GIF image can be regarded as an array of frames. One frame is captured for moderation from every n frames, where n is specified by the interval parameter. The system captures frames from GIF images only when this parameter is specified. Long images can be in portrait or horizontal mode. To moderate a long portrait image, you can calculate the total number of frames in the following way: divide the height by the width and round the result to the nearest integer. In a long portrait image, the height is greater than 400 pixels, and the ratio of height to width is greater than 2.5. To moderate a long horizontal image, you can calculate the total number of frames in the following way: divide the width by the height and round the result to the nearest integer. In a long horizontal image, the width is greater than 400 pixels, and the ratio of width to height is greater than 2.5. By default, only the first frame of a GIF image or a long image is moderated. You can use the interval parameter to specify the interval between two frames that the system consecutively captures. This helps reduce moderation costs. Note The interval and maxFrames parameters must be used in pairs. For example, the interval parameter is set to 2 and the maxFrames parameter is set to 100 for moderating a GIF image or a long image. In this example, one out of every two frames is moderated and a maximum of 100 frames are moderated. The fee is calculated based on the actual number of moderated frames.
maxFrames	Integer	No	100	The maximum number of frames to be captured. This parameter is dedicated for GIF or long image moderation. Default value: 1. If the value of the `interval` parameter multiplied by that of the `maxFrames` parameter is smaller than the total number of frames in a GIF image or a long image, the interval for capturing frames is automatically changed to the integer rounded from the result of dividing the total number of frames in the image by the value of the maxFrames parameter. This helps improve the overall moderation effects.

Response parameters


Parameter	Type	Example	Description
code	Integer	200	The returned HTTP status code.
msg	String	OK	The message that is returned for the request.
dataId	String	test_data_xxxx	The ID of the moderated object. Note If you set the dataId parameter in the moderation request, the value of the dataId request parameter is returned here.
taskId	String	img5A@k7a@B4q@6K@d9nfKgOs-1s****	The ID of the moderation task.
url	String	https://aliyundoc.com/test_image_xxxx.png	The HTTP or HTTPS URL that can be accessed over the Internet. The URL is up to 2,048 characters in length.
results	Array		The returned results. If the HTTP status code 200 is returned, the array in the returned results contains one or more elements. Each element is a structure. For more information about the structure of each element, see result.

Table 2. result
Parameter	Type	Example	Description
scene	String	ocr	The moderation scenario. Set the value to ocr.
label	String	ocr	The category of the moderation result. Valid values: normal: The image does not contain text. ocr: The image contains text.
suggestion	String	review	The recommended subsequent operation. Valid values: pass: The image does not require further actions. review: The image requires manual review.
rate	Float	99.91	The probability that the moderated image falls into the detected category. You can ignore this parameter in the OCR scenario.
ocrLocations	Array		The information about the single text entry in the moderated static image, which includes the text, text size, and text location. For more information about the structure, see ocrLocation. Note If no text is detected in the moderated image, this parameter is not returned.
ocrData	Array	["hello, this is a test text."]	The combination of all text in the moderated static image. In general, the text combination is stored as the first element of the array. Note If no text is detected in the moderated image, this parameter is not returned.
frames	Array	xxx	The frames that are captured from the moderated animated image and the text that is detected in each frame. Note If no more than one frame is captured, this parameter is not returned.

Table 3. ocrLocation
Parameter	Type	Example	Description
text	String	hello	The single text entry that is detected in the moderated image.
x	Float	41	The distance between the upper-left corner of the text area and the y-axis, with the upper-left corner of the image being the coordinate origin. Unit: pixels.
y	Float	84	The distance between the upper-left corner of the text area and the x-axis, with the upper-left corner of the image being the coordinate origin. Unit: pixels.
w	Float	83	The width of the text area. Unit: pixels.
h	Float	26	The height of the text area. Unit: pixels.

Examples

Sample requests

http(s)://[Endpoint]/green/image/scan
&<Common request parameters>
{
    "scenes": [
        "ocr"
    ],
    "tasks": [
        {
            "dataId": "test_data_xxxx",
            "url": "https://aliyundoc.com/test_image_xxxx.png"
        }
    ]
}

Sample success responses

{
    "code": 200,
    "data": [
        {
            "code": 200,
            "dataId": "test_data_xxxx",
            "extras": {

            },
            "msg": "OK",
            "results": [
                {
                    "label": "ocr",
                    "ocrData": [
                        "hello, this is a test text."
                    ],
                    "ocrLocations": [
                        {
                            "h": 26,
                            "text": "hello",
                            "w": 83,
                            "x": 41,
                            "y": 84
                        },
                        {
                            "h": 25,
                            "text": " this is a test text.",
                            "w": 95,
                            "x": 78,
                            "y": 114
                        }
                    ],
                    "rate": 99.91,
                    "scene": "ocr",
                    "suggestion": "review"
                }
            ],
            "taskId": "img5A@k7a@B4q@6K@d9nfKgOs-1s****",
            "url": "https://aliyundoc.com/test_image_xxxx.png"
        }
    ],
    "msg": "OK",
    "requestId": "C4AB08A9-AD75-4410-859B-0B9EF6DFC3C4"
}