I. Concept of Grayscale

Grayscale refers to the division of luminance variations between the brightest and darkest points into different levels. It is generally divided into seven rough levels: white, grayish-white, light gray, gray, dark gray, light black, and black. Each level represents a change in luminance, largely reflecting the image's ability to resolve details at different brightness levels. The more levels that can be distinguished, the better the resolving power, and the finer the resulting image quality.

II. Grayscale Testing

Grayscale testing involves setting up a scene that transitions from white to black and then capturing images of this transition using a camera device. The more distinct the grayscale levels appear in the captured image, the better the grayscale response capability of the camera. In simple terms, grayscale testing evaluates the luminance difference between adjacent patches. Generally, the greater the number of luminance differences that meet the standard, the more distinct the grayscale levels.

2.1 Test Equipment:
TC-RQ-14 reflective grayscale chart, camera module, image acquisition card, chart holder, lifting table, fixture, fill light, image capture software, RIQA, illuminance meter;

2.2 Test Procedure:
1. Environment Setup
(1) Mount the TC-RQ-14 reflective grayscale chart on the chart holder. Perform this in a dark environment and adjust the position, direction, color temperature, and illuminance of the vertical multi-color-temperature fill lights according to the test requirements;
(2) Use an illuminance meter to measure the illuminance at the top, bottom, left, right, and center of the chart to ensure it reaches the required illuminance;
2. Sample Image Capture
Secure the module with a fixture, select an appropriate shooting distance based on the module's FOV, and use YanDing Capture to capture the sample images;
3. RIQA Analysis
(1) Open the RIQA software, click “OECF Q14” in the “Grayscale” module, and click “Add” to add the images to be analyzed.

(2) Select the image, click “Start”, and draw a box to select the approximate analysis area.

(3) Click “Next” and precisely draw a box to select the analysis area.

(4) Click “Analyze” and then “Generate Report”. Enter the report name, save path, and report type, and click “Export” to view the report in the specified path.

4. Result Analysis: Open the file with the .csv extension and locate the pix_Y column in the data under the grayscale patch pixel values.

Typically, we look at the number of adjacent grayscale patches in this column where the difference between two consecutive values is greater than 8.

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camera测试用例, 测试用例, riqa简介