SIGNIFICANCE It is commonly assumed that using the objective lens to create a tightly focused light spot for illumination provides a twofold resolution improvement over the Rayleigh resolution limit and that resolution improvement is independent of object properties. Nevertheless, such an assumption has not been carefully examined. We examine this assumption by analyzing the performance of two super-resolution methods, known as image scanning microscopy (ISM) and illumination-enhanced sparsity (IES). AIM We aim to identify the fundamental differences between the two methods, and to provide examples that help researchers determine which method to utilize for different imaging conditions. APPROACH We input the same image datasets into the two methods and analyze their restorations. In numerical simulations, we design objects of distinct brightness and sparsity levels for imaging. We use biological imaging experiments to verify the simulation results. RESULTS The resolution of IES often exceeds twice the Rayleigh resolution limit when imaging sparse objects. A decrease in object sparsity negatively affects the resolution improvement in both methods. CONCLUSIONS The IES method is superior for imaging sparse objects with its main features being bright and small against a dark, large background. For objects that are largely bright with small dark features, the ISM method is favorable.

中文翻译：

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分析聚焦点照明方法的超分辨率特性。

意义 通常认为，使用物镜为照明创建紧密聚焦的光斑可提供超过瑞利分辨率极限的两倍分辨率提高，并且分辨率提高与物体属性无关。然而，这样的假设并没有被仔细研究过。我们通过分析称为图像扫描显微镜 (ISM) 和光照增强稀疏 (IES) 的两种超分辨率方法的性能来检验这一假设。目的 我们旨在确定两种方法之间的根本区别，并提供示例以帮助研究人员确定针对不同成像条件使用哪种方法。方法我们将相同的图像数据集输入到两种方法中并分析它们的恢复。在数值模拟中，我们为成像设计了不同亮度和稀疏级别的对象。我们使用生物成像实验来验证模拟结果。结果在对稀疏物体成像时，IES 的分辨率通常超过瑞利分辨率限制的两倍。对象稀疏度的降低会对两种方法的分辨率提高产生负面影响。结论 IES 方法在对稀疏对象进行成像方面是优越的，其主要特征是在黑暗的大背景下明亮而小。对于大部分明亮而带有少量暗特征的物体，ISM 方法是有利的。对象稀疏度的降低会对两种方法的分辨率提高产生负面影响。结论 IES 方法在对稀疏对象进行成像方面是优越的，其主要特征是在黑暗的大背景下明亮而小。对于大部分明亮而带有少量暗特征的物体，ISM 方法是有利的。对象稀疏度的降低会对两种方法的分辨率提高产生负面影响。结论 IES 方法在对稀疏对象进行成像方面是优越的，其主要特征是在黑暗的大背景下明亮而小。对于大部分明亮而带有少量暗特征的物体，ISM 方法是有利的。